Building Science Meets Mountain Climate with Joseph Lstiburek, Ph.D, P.Eng.

[Music] [Applause] [Music] good evening everybody my name is Joe stearic and I can see a lot of you had nothing better than to do on a Tuesday night than to come to hear an old guy tell stories that may or may not be true just as we get started some some ground rules there really aren't any please feel free to ask questions as as they come up if I say something particularly irritating you know ask me about or a challenger or whatever I'm hoping that this will turn into dialogue rather than just be a monologue I don't view the questions as an interruption also the PowerPoint that I be using you know you can download I'll post it online in about a week or so from our our website building science comm there's no secrets in building science so please feel free to email and we'll try to get information to you I get about 500 emails a day so be patient 480 of them are from banking opportunities and I in Nigeria and and viagra ads I don't know how they know that I need apparently both of those services but what they do so you know be be be patient we're we're not a we're not a we're not a big firm we're just having a hell of a lot of fun a little bit of background I've been coming to Aspen and and Carbondale since the mid 1980s and it sort of turned my my career around and so I use this as my home not just a place to hang out and and ski and drink expensive line so I have a lot of friends here and some who have known for 20 30 years it's kind of nice to come come back here so with without further ado mmm-hmm I thought I'd start by defining what a building is and a building is a different thing to different people from a building science perspective it's an iron metal separator it keeps the outside out and the inside end makes sense you know which immediately puts us in conflict with architects who are always trying to connect the inside to the outside and the outside to the inside sometimes the outside sucks and you don't want it inside sometimes the inside sucks and you don't want the insight and the thing that separates the inside from the outside if I'm going too fast stop me here I realized that these are complicated concepts what are the odds that that thing that separates the inside from the outside is going to be done perfectly well slim to none and slim is just left town right so sometimes the inside is going to get into the thing that separates the inside from the outside and we have to decide whether to let it through or kick it back and sometimes stuff from the outside gets into the thing that separates the inside from the outside and we have to decide whether to kick it back or let it through make make sense now how much we kick back and let through in each direction depends on on four things in my opinion a lot of people don't like to admit that what they're saying is an opinion now I think I have pretty good basis for my opinions but it's an opinion all right you are free to make your own decision so the first and foremost from my perspective is where is the building located there's a big difference between Miami in Minnesota so the physical location of the building establishes the external environmental load right how much rain what's the temperature what's the relative humidity how much snowfall does the earth move under your feet okay that was a Carole King song that apparently I am a generation or two removed from I actually saw Elvis when he was thin okay it's just to let you just to let you know so the location of the building establishes the external environmental load and it matters a great deal there's there's no shouldn't be controversy there but how can you have one building design for the entire country that makes no sense but there you go you can have one burger chain that makes the same burger but it probably shouldn't be manufactured in the same building just the thought well that's number one number two would be the internal environmental load right what's going on inside there's a big difference between a warehouse and a humidified pressurized hospital art gallery Museum swimming pool or whatever right so we need to know two things now what's the external environmental load what's the internal environmental load the third thing this gets more controversial now is what makes up what materials make up that environmental separation there's a big difference between building out a thousand year old trees and rocks and out of was wood was wood it used to be wood but it's not wood no more engineered wood is an insult to both wood and to engineers OSB is the spam of wood spam is the OSB of luncheon meats these are really good lines folks on this is I mean you know you know cut me up coming a break here okay you you you youngsters apparently don't get this but let me just let me explain we used to go to places called forests and cut trees down and we would cut them into boards and make boats out of them and sail them around the world try doing that with a sheet of OSB right so you really think that the stuff you're building out of hasn't changed we used to have wet applied interior finishes they had plaster now we have drywall paper face gypsum and we line the entire entirety of our buildings with paper we're building paper buildings even the dumbest of the Three Little Pigs didn't build his house out of paper back in the day the big bad wolf would huff and puff all he does now is lift his leg so you really think that you can still do the stuff that you used to do which you can't now what are the odds that we're going to go back to build out a thousand roll trees and rocks and it's not going to happen alright so number one is the external environmental load number two is the internal environmental load number three are the materials that comprise the environmental separation number four is why I don't get invited usually to the US GBC green programs and why I don't get invited to the architectural galas and I'm not I'm not welcome in Georgetown anymore except when they screw up their house its energy what have we done to the energy exchange of our building enclosures we've dramatically reduced it right and what are the odds that we're going to continue to do that it's gonna happen well guess what there's no such thing as a free thermodynamic lunch I used to say you can't get your money for nothing and your chicks for free but apparently that sexist but I'm old enough that I don't care you see I can't be fired I'm a legend so I can tell stuff that would get other youngsters into trouble look we build stuff outside and it gets wet and we build out of wet materials we've always been doing that that we haven't had trouble if the materials could dry repeated wetting followed by repeated drying has never been an issue especially if you've been building out a thousand rural trees and rocks drying involves an energy exchange the more energy inefficient the building is the higher the drying potential you could do stupid stuff in a poorly insulated building you can't do stupid stuff and an extremely well-insulated building people were running around saying Oh save energy makes the building work better is all easier liar liar pants on fire you have to be really freaking good because there's no room for error anymore you know enter this energy thing I'm by the way I'm an engineer three times over I'm born with the genetic defect as most engineers are it's the efficiency gene right I I was into this energy thing before it became a cool thing to be into the energy thing I mean I've been doing energy efficiency for 40 years but I learned that it doesn't come for free without consequences the more energy efficient you make your building which I want you to do by the way the lower the drying potential which means you have to intervene on preventing it from getting wet in the first place or design around the water sensitive materials that means oh my god I can't put stucco over OSB anymore I have to put an air space behind it well why well because I used to put it over boards and in poorly insulated wall now I'm putting it over OSB with fluffy up the yin-yang that's a metric term it's too was ooze so I have to compensate for that so I'm not anti efficiency I'm not anti the materials I'm just telling you that it's different now all right and because it's different and people aren't accepting that fact we're getting failures and I rarely get a call Joe Joe it's freaking fabulous come on let's have a beer I don't get those calls I get the call to 3:00 in the morning the vampires are coming the is that the fan it's the end of the world they're taking my house and the kids in whatever half all right and so we have more problems because we're not accepting the fact that energy comes with consequences I do not want to go back to energy inefficient uncomfortable buildings and we're not going to be building out a thousand year old trees and rocks but we have to do it differently so that's the politics apparently I farted in the cathedral and I'm not invited anymore so here are the rules for environmental separation they're not mine this is from the 1950s before I was born there 14 of them they're not equally important the ones that'll kill you are more important than the ones that will irritate you really and the ones that will kill you quickly are more important than the ones that will kill you slowly and the ones that'll irritate you quickly are more important than the ones that leader takes you slowly they're you with me on this so you have to prioritize it's not a good idea to kill people [Music] the English forgot that had Granville towers 80 people died in a super energy efficient retrofit nobody's talking about it oh it burned and they died well yeah what started the fire well a refrigerant leak with a flammable refrigerant what do you people nuts well it has a high as a low greenhouse gas potential yeah but it burns we stop doing stupid like that in the 30s what are you insane and so let's wrap the building with flammable stuff well yeah but we saved a lot of energy it looks cool stop it stop doing stupid stuff it'll kill people that's not a popular message until I told you this how did do how many of you even knew that it was a stupid design it would have never happened here because of an old guy by the name of Jesse who came up with NFPA 285 which makes us burn the walls before we build them well we never have to do that before well it's because fires went up the inside of a building and we learned to compartmentalize jesse Beitel said well wait a minute the fire can go up the outside and pop in and that's what happened we we need to you just can't wrap the outside of your building with stuff without understanding that you've dramatically changed things I want you to wrap the outside of your building okay I do you just have to do it differently because it's important not to kill people except the ones that deserve it that's meant as a joke I don't think all right we're focusing on the top part of the list today because we've really done a really good job most of the time on the bottom part of the list you know we not too many people die would be nice to keep that record we are making people sick right okay rainiest equation nothing excites me more than the third most famous equation in physics I can see you're all educated in the United States and are therefore clueless it's vonti Irenaeus won a nobel prize in physics at the turn of the last century was a huge scandal because he was a chemist nothing pisses off physicists more than the chemist okay let me explain how this works a chemist - a physicist is like holistic medicine - a brain surgeon I guess that hits too close to home here and never mind basically what he said for every 10 degree K rise in temperature the reaction rate doubles well okay let me translate 10 degrees K is 10 degrees C 10 degrees C is 18 degrees Fahrenheit using gel math which is a field of mathematics I invented that's around 20 degrees for every 20 degree fahrenheit increase in temperature you double bad [Music] you want things to last a long time make them colder so a white roof will last two to three times longer than a black roof I did this presentation in st. Louis entitled it why Drew's matter too too soon for that joke apparently it's too soon for that that joke the trouble was that the white membranes did last longer but the roofs themselves rotted faster well what does the white roof do to the drying potential it reduced it so when we changed the color of aru's from black to white Roose couldn't get as wet as they used to because when they got when they were black and they got wet the Sun would drive the water back into the building the moment we started changing the color that didn't happen so we had to change the way we constructed roofs we suddenly had to introduce air barriers and vapor barriers on the underside of the roof assemblies to compensate for the fact that we changed the temperature profile when you stand that up and we call it a wall do you see how this okay yes it's in case never mind so the three principal damage functions that are governed by the Iranian or water heat and ultraviolet light so that's the badness that happens and of the three water is the most significant so if you want things to last a long time keep them dry keep them cold and protect them from ultraviolet light you want to live a long time move to a place that's very very cold that's very very dry and cover yourself up so you're not exposed to ultraviolet light and eat nuts and berries you will live a long time but feel miserable and wish you were dead [Music] nevermind alright a second law of thermodynamics that's a big deal there are four laws of thermodynamics but we only number them to the third law because we forgot one and so you know we had the first second and third law for about a hundred years and all of a sudden somebody said we forgot one and we didn't know where to put it because we didn't want to renumber everything so we called it the zeroth they never asked me I I would have said they didn't make sense because the zeroth law says if a equals B and B equals C a equals C you know a dead Greek guy by the name of Aristotle wrote it down a long time ago but apparently the Germans didn't get it so I guess it was all Greek to them alright so here's the second law of thermodynamics heat flow us from warm to cold because that's that's what it is it's you when you call something a law you call it a law because you have no other explanation for it you can't derive the second law of thermodynamics for first principles you just say it's a frickin law until somebody finds an exception so you can never prove science you can only disprove science despite what the Washington Post and CNN says science is never settled the only people that say science is settled and it's proven are arts graduates [Music] anyway nobody's found exceptions to this but nobody can derive from first principles these things hence they're a law until they're proven otherwise Moisture flows from warm to cold moister flows from mortal s why well because you could do this experiment at home you could take something wet and touch something dry dry thing becomes wet son-of-a-bitch who knew that a bunch of Germans 150 years ago yeah all right air flows from a higher pressure to a low pressure and gravity acts down now the ones that we are really concerned with our warm to cold inmortal s so when your building is heated and it's cold outside what directions the moisture flow from the inside out when it's hot outside and cold inside when your air conditioning the moisture flows from the outside in so I would be a really stupid idea to put vinyl wallpaper on the inside of an air-conditioned building in New Orleans [Music] right it's hot and wet outside and we want it to be cold and dry inside vinyl wallpaper would be stupid and if you put an exhaust fan that pulls all of the air out of the bathrooms you get a negative pressure so you get a building that sucks with a condom on the wrong side we call that a hotel right the mole deist buildings in the United States of America are air-conditioned hotels and hot humid and mixed Seamas climates with exhaust only ventilation and vinyl wall coverings right that works in Vegas why well what happens in Vegas stays in well you can suck in Vegas because it's dry there's not going to be any problem right alright so you have to blow in New Orleans you have to be under a positive pressure right this is too hard for you stop me this is you know the second law nobody teaches it this way because it's simple and logical and if civilians understood this the whole system is in jeopardy so warm to cold more to less we don't teach that because people understand it so we say no it's the thermal gradient and the concentration gradient as thermal diffusion and molecular diffusion we call it vapor diffusion we say it's the thermodynamic potential and we use this chart to explain it are you kidding me look at this Luke turn off the psychrometric chart go with the force the water's going to end up on the cold surface they don't let me teach undergraduates anymore yeah Steve Rick does a good job with the doctoral students but you know we just can't expose the youngsters to this so 15 to 18 times out of 20 the water always ends up on the cold spot so if you already know that those are great odds why waste your time with stupid calculations the way you keep water from accumulating on a cold spot is don't make the spot cold that's why I get paid the big bucks [Music] for those of you who are American high school graduates has never seen this before this is a map of North America there are only two seasons up here this winter and last winter there are only two seasons down here hot and wet and hotter and wetter you should probably appreciate the difference are you more Minnesota or more Miami here you're more Minnesota right just come on this is now this is my big contribution to building physics this is my map and this is was eventually turned into the IECC climate zone map and so would you like to know where I got this map I stole it from a dead guy it's important to steal things from dead people [Music] this is based on the köppen climate definitions of a hundred and fifty years ago copan basically this is you know vegetation i decided that the plant kingdom is a better judge of environmental loads than architects and engineers so he basically used the plant kingdom to define external environmental loads for buildings late at night a bartender and basalt will be impressed with this all right so this is based on my chart which is based on copan which is based on the plant kingdom just in case you wanted to to know the other map is a map of rainfall and i chose 20 inches of rain as a as a separation because 10 would make it too complicated and 30 would not make it complicated enough well who put me in charge I did I wrote a book and became famous and you know screw you you write a book and become famous and spent 20 years then you get to make your own damn map why this is important is that people are going to have to change the way they've designed their rain control based on the load right it's real easy to deal with Vegas where it rains 20 you know you know what 10 inches of rain a year whereas in Biloxi Mississippi it rains 10 inches of rain an hour well so Vegas is low rainfall Biloxi is high rainfall [Music] Vegas is hot dry Biloxi is hot humid what's common to Biloxi and Vegas casinos you people don't get out very much the point is is you can't build the casinos the same way in Velux ii that you build in in vegas but yet they are because they're operated by the same companies the same architects the same financing and that's that's insane right just buildings don't get wet uniformly [Music] we have problems at the bottoms of lindos there are only two kinds of windows in the world windows that leak and windows that will leak what do we know about windows it gets worse when those are like people as windows and people get old we leak you youngsters have no freaking idea what's coming so what's your highest risk where the building touches the sky where the building touches the ground and the punched openings right not a hell of a lot happens in the field of the wall that's not where you're gonna win or lose the game roof roof roof roof foundation foundation foundation holls holls holls holls then take a valium and relax that that was a drug that nevermind here we're so freaking young anyway so if you wanted to really get down to brass tacks that's an old expression that you should look up after you've handled the fire and structure and other stuff you really need a wall and a roof and a foundation to have a water control there not water control layer is more important than the air control there you want an air control air but it's nowhere near as important as a water control layer both are more important than a vapor control air and all three are way more important than the thermal control there I have a lot of fun with above the air barrier Association of America I mean I like first of all why would you want to name something after a bad swedish group that slept with each other we should have had a wobba before we had an Abba we should add a water control Association before we had an air control Association if you look at the ABBA but I was their keynote speaker a couple of years ago and they're like yeah I know it was fun it was great I had more fun than the Grammys I'm not running for anything right now if you look at the Abba specifications or air barrier requirements what they really are are water control layers that have an air control function but make no mistake about it the water control function is more important than the air control function I've been doing this for over 40 years and I've never gotten a call at 3:00 in the morning saying my building is leaking air that that call doesn't happen so let's say I was in charge which I'm not what would the perfect wall look like there it is there's the structure the black line is the water control layer it's the air control layer as well it's the vapor control air the blue layer is the thermal control air is blue in color because Dow paid me to make it blue later on it'll be pink in color that's Owens Corning and it's when it looks vomit orange that's rock wool how could they pick a color like well they'd be mean whatever outboard of that is the cladding that's back ventilated and drained and this configuration works everywhere in the world all of the time that's why it's called the perfect wall if I'm in Montreal and it's hot and wet inside under positive pressure let's say I am building an art gallery Museum Hospital data processing center natatorium connected to one another it's probably an Aston project and it's really cold so the moisture flow is from the inside out so what happens is the moisture blows through the wall and it's this black line and what happens absolutely nothing because the line is warm although the insulation is on the other side so I don't have a change in phase and nobody cares now what are the odds that the québécois those poutine eating maple syrup slurping hockey playing french speakers get it right watch from Montreal give me a break they're gonna screw it up but it doesn't matter because if the stuff gets into here won't hang out there very long it will get into this airspace and go to the outside so it fails in a fail-safe manner it doesn't matter what the insulation is could be extruded polystyrene expanded polystyrene foil faced Isis saying you and mineral rock well it doesn't matter they all work in this configuration I don't have to I don't have to do any calculations this just works from first principles well you didn't do a wolfy analysis well if you need to do a wolfy analysis you're an idiot because you don't know enough to know that you don't need to do one now ask me if we do wolfy analysis all the time you know why it's really profitable I love to do unnecessary expense of consulting have you any idea how expensive tires are for a Porsche well we just need something for the file I love that it's you know this is basically a tax on stupid people right so you got some MBA Harvard Graduate or word and graduate wanting to protect their investment so you have to do a hydrothermal analysis and they're saying no you don't if you design it with first principles you don't have to do anything well we need something okay do you want the expensive analysis or the cheap one well what do you recommend dr. Steve Rick I recommend the expensive analysis so let's take it to Miami and it's hot and wet out here and cold and dry in here and what happens to the moisture blows through this lake through a goose and it hits the black line and now what happens well it condenses the changes from a vapor to a liquid oh my god I've got water on my water control layer you'd be surprised at how freaky that is now what are the odds that those sandwich squashing cigar smoke and Mambo dancing South Beach folks are gonna get it right well about the same odds as the Quebec want act a vacation together everybody for Montreal goes to Miami Toronto we've always hated I'm from Toronto Ashley we've always hated Montreal so we vacation in Fort Myers C we don't get along in Canada and we can't even vacation together the way you tell us apart is the English speakers tip so this will be flawed so stuff will get in here what's important is to let it to get out of here and to here so what would you never have on the inside of that wall vapor barrier no vinyl wallpaper if you have a mirror on the wall you have to back ventilate the mirror you hang cabinets cabinets used to be made out of real wood now they're made out of was wood right so you have to back ventilate your cabinets you can't hang pictures on the wall with glass because they're vapor barriers so you have to put an air gap behind your pictures if you go to the Louvre the French have a nineteen millimeter gap behind all of their artwork what's so special about nineteen millimeters it's the diameter of a Bordeaux wine cork you're not sure whether I'm bullshitting you here or not and that's important you should do your own research back in the day youngsters in the 60s would say distrust Authority apparently you youngsters aren't asking questions stop it ask questions don't believe anybody anyway so we don't want a vapor barrier on the inside if we lay it down we get the perfect roof we flip it the other way we get the perfect slab the physics for walls roofs and foundations are the same Wow so this is the perfect roof the membrane is under the ballast in the insulation it's protected from ultraviolet light and heat so the Iranian equation is working for you right we call it a protected membrane roof if you replace the ballast with dirt grass and a goat you get a LEED point does the dirt grass and a goat make it work better no but you just feel better about yourself in dirt is not insulation it's just freaking dirt if it was insulation we'd put it in our walls and that would be stupid well what about the green well you could paint it white well we can store water up there why you're an idiot the whole idea of a roof is to get the water off of the damn roof well it's green and sustainable well why well because you've not invested in civil engineering infrastructure so you're making the homeowners and the property owners compensate for the fact that you've been doing stupid stuff with with with statues and instead of dealing with sewers and roads and water management what are you nuts putting the water in the top of your building then you have a drought and the grass becomes a fire hazard in California we had to sprinkle our rubes to keep them from burning in the middle of a damn drought you guys are nuts and asked me if I like green Roos yeah when they make the building look beautiful are you freaking kidding me I'm tired of ugly boxes that chase every last beats you why can't we have beautiful stuff I'm willing to give up performance for beauty when you rise up you don't want some you know lead checklist Nazi dictating architectural and engineering and contractor design you know grow a pair no I want this building to be beautiful let me explain why it's important for it to be beautiful you're all talking about sustainability and all of this nonsense what's a sustainable building it's a building that lasts a very long time and guess what in order for it to last a long time people have to take care of it and for a building to be taken care of people will won't have to want to take care of it and people don't take care of ugly things ugliness is not sustainable give me a beautiful freakin building that people want to live in and work in they'll take care of it now you've created a machine that consumes resources so now you make it ultra efficient but don't give me an ugly square box I'm tired of Passivhaus is that too close to [Music] don't do this too for the lead point why don't you go with the bite Drac instead but if you're gonna do this for the right reasons I'm there for you flip it around you get the perfect slab right dirt stones your insulation your plastic sheet in your concrete doesn't get better than this then we put it all together now comes the aha moment we have to connect them building performance and durability is all about continuity of the control layers you connect the water control of the roof to the water control of the wall to the water control of the foundation the air to the air to the air the vapor to the vapors of the vapor the thermal to the thermal to the thermal simple then what do we do you know we put holes in it and so there shouldn't be complicated but all you need to do is connect the water control of the window to the water control of the wall the air control of the window to the air control of the wall the vapor to the vapor the thermal to the thermal put it in plumb level and square so that you can operate it and fasten it so that the wind doesn't suck it out and we're done I've just compressed a 400-page ama ASTM document on how to install windows now the problem is is that the manufacturers of Mideast products don't tell you what element does what function and when they do I don't trust them anyway so for years I've always insisted that we connect to the back of the glazing system that way when it event in Ewa tably fails the consequences of the failure are directed to the outside right a leak is not a leak if the client never sees it repeat after me a leak is not a leak if the client never season now because it's expensive to do the ballast and stuff we'd basically end up not having a protected membrane roof we end up having a roof with two membranes the upper membrane is the water control and the lower membrane is the air and vapor control everybody with me on that this is this is what you're going to end up with eight times out of out of ten unless you are doing an institutional building or a client that has enough money that will allow you to do amazing things so that's there are other places besides to Aspen and Naples Florida that have budgets so that means that your air control and vapor control on your roof ties in at the wall and has to go through the parapet whereas the water control esta wrap over the top of the parapet ready with me on this all right all right residentially I can just move the water control upwards and create an air gap and that air gap is a really big deal in a cold climate because I want to ventilate the Attic and have it filled with cold air so they don't have ice damming already with me on this this is you know a big deal wherever the ground snow load is greater than 50 pounds of square foot you need a heavily ventilated attic and you want a thermal resistance of it between our 50 and our 60 to control the ice dams if you're not doing that you get basically the Sun Deck an ass you know when a design of work we sent them immediately a proposal for Forensic Services see if you get an award it's not gonna work it's called targeted marketing you can turn it into a cathedral if you take away the airspace that will only work if you don't have a lot of snow all right good for cold climates with snow bat this is great in Florida how this works in Boston doesn't work in New Hampshire well I don't know what you call it people keep people just a ventilate it but this is they call this a cold roof but if we do our job right this is freaking cold - okay well I'm I'm teasing you yeah I mean I was like that the trouble is is that this is also a cold roof until snow falls on it the r-value of snow is between R 1 and R 2 per inch so if I now have 20 inches of snow I could have our 40 on the top of the roof and that black line at the top is now freakin warm it's no longer cold you're from you came you came from Vail is that allowed all right I think that's a bad idea - stop it - stop it well I'm going to show you some failures if I get around to it on our website I talked about de-icing ice dams and damn ice dam those are two papers that you can read but we've seen our 60 and our 70 brews without an airspace have serious ice damming but we have to have a lot of snow if you don't have a lot of snow not a problem you can do with spray foam but it has to be closed cell you can't use open cell and cold climates stop it despite what the salesman tell you configurations of the perfect wall this is call this it's an institutional wall we call it the 500-year wall for three reasons one it lasts 500 years - it represents 500 years of evolution and three you'll take your clients 500 years to pay for this it's insanely expensive but it's freaking magnificent so if you want something to last for a long time this is how you do it yeah I mean you you build it out of rocks because rocks don't burn you lining with sheet rock on the inside because rock stone burned and you put more rocks on the outside because rocks don't burn you can make this out of fluffy rocks because rocks don't burn [Music] but you could put napalm in there and it won't burn either because you got rocks on the other side that's why dal likes this see they made napalm and a little squabble called Vietnam never mind you're the next version of that is commercial wall all we've done is we've taken the rocks and simplified the construction with steel studs and gypsum sheathing but the control layers are all on the outside notice that there's no insulation in here because insulating a steel stud wall is a thermodynamic obscenity if you took a six inch steel stud and insulated it with a six-inch batt you're gonna go from our 20 to our five you lose 75% of the thermal resistance because the conductivity of the steel steel is 300 times more conductive than wood you know how I know this I've never seen wood wiring I've never seen a wood frying pan well once so how do we insulate steel studs we have to put insulation on the outside I learned this as a child growing up in Canada as all Canadian children earn learn at an early age when it gets cold you pull the sweater over the outside of you you don't eat it and shove it into your ribs you want to be a sweater we're not a sweater eater now is there a reason to insulate the steel studs and the answer is yes acoustically because it becomes a drum so you use fluffy stuff for the acoustics and then whatever you want on the outside for the thermal does that make sense now residentially when we're building out a wood again this is the perfect configuration and what's neat is you can use any insulation you want here or here you can use fiberglass cellulose damp spray cellulose dry spray Salus in the net you use ground-up blue jeans it doesn't freakin matter on the outside any rigid insulation system that you want they all work what's important is the order not so much the material but the order you can pick your teeth pick your nose pick your butt but the order matters you are never going to forget that's saying and I've done my job now notice that these are done with a vapor barrier and I'm here to tell you that you can do them without a vapor barrier if you get the right thermal resistant resistances correct done right so in other words you can have a flow through assembly or a non flow a throat assembly both work a little bit further with the wool to draw it I looked at all the dry and okay fine I don't care you can do it that way well I prefer to do it this way okay it's a ginger Mary Ann thing there's no wrong answer [Music] nevermind okay how many men in here or our fifty years of age or older okay this is just for you we're discriminating answer everybody else show of hands Mary Ann or ginger Mary Ann ginger Wow that's the first time in ten years that it's been tied most of the time Mary Ann wins go figure well alright it doesn't matter [Music] so let's look at evolution of walls a little differently this is a wall without insulating sheathing it's worked really well I mean I would build a 2x6 with plywood have an air gap between the cladding and the plywood I'd have a water control layer on the on the plywood it could be Tyvek type our tar paper fluid applied whatever and I got an air gap at least you know 3/16 of an inch I'm you know 3/4 is more than you would ever need but something and that's a spectacular wall it's gonna last a long time it's not particularly energy-efficient but you know it's it's gonna do its job if you want to improve the thermal performance add a layer of insulation on the outside now how much of a layer do you need to add well the r-value that you add is necessary is to determine by not having a plastic vapor barrier on the inside and the building code the IRC and the IMC and the IBC says if you look at the table it'll tell you what percentage of the total thermal resistance needs to be on the outside so that you don't have to have a vapor barrier on the inside the reason we don't want a vapor barrier on the inside is because stuff happens right and we want the wall to be able to do what to to dry now normally the practical limit of thickness for one layer is 2 inches inch and after 2 inches because you don't need furring strips now to attach your standard cladding you can attach hardly border wood siding or vinyl siding or whatever over an inch and a half or two inches of rigid insulation you go above that and you're going to need to do furring strips and so the next step is go to two or three inches of rigid insulation on the outside when I say rigid it could be rock wool or mineral wealth you know it's semi-rigid and then you have a you know 1x4 furring strip with a long screw eye on our barn 20 years ago I have eight inches of rigid insulation with held in place with you know long wood screw you know no big deal so you know I think if I was building in Basalt I would probably have a 2x6 wall with you know OSB and I'd probably choose Hueber zip because I could tape the joints and that would be my water and air control there and then I would have to two-inch layers of rigid insulation pick any one that you like you know if you don't like the fire retardant here or you don't like the environmental impact of that I don't care you know you you you can use whatever criteria you want on making that decision my approach is not to irritate my clients my clients are set on having this kind of an insulation system grape and going to do it and then you know so I'd probably put four inches to two inch layers of either extruded polystyrene or foil faced Isis a narrator Rockwell depending on what the client likes Minow one by four with screws and fiber cement that's going to give me in our forty to our forty five wall how could you argue with that you want to go to Net Zero that's where you start all right you want to go farther you can put a truss on the wall and get yourself in our sixty wall on an RA T wall build a double wall but the water and air control lair is here and then we have an addition water can water control layer there yes sir I am they're difficult to work with I don't use them as ultra high performance can you make them work well yeah absolutely that what you want is you want to make sure that whatever cladding system you put on the wall has to have an air gap behind it because nobody can figure out how to make those joints airtight enough which is not going to happen remember that sip wall can't dry into the foam core it can only dry to the outside so it has to have a gap when you're building your roof you absolutely have to have at least a two inch to two and a half inch gap because of the ice damming issues right and there's no way you're gonna make that sip panel joint airtight enough because there's gonna be leakage and you have to compensate for it now you try you're really freaking try to make it airtight underneath but I'm here to tell you you will not succeed now I wrote a book on sips telling you how to how you can do that I used to own a sip company I only lost three-quarters of a million dollars on that one I found I could make more money talking about things than actually doing them who's gonna ask me about ICS apparently nobody's got the courage to ask me what ICS they work but their architectural II limiting right we build a lot of apartment buildings them out of them in cold climates because it we can't have large windows so they're ultra efficient because the architects are prevented from having big windows windows are big freakin thermal holes if somebody says I've got a high-performance building that's all glass I kind of roll my eyes you're an idiot probably a McGill graduate semi-good University in Montreal asked me why we hate Montreal so much because they keep winning Stanley Cups my Toronto Maple Leafs have not won in 51 years six months 14 days three hours but this year the best player on the Toronto Maple Leafs is an American from Arizona you're all welcome in Canada by the way because she sent us Austin Matthews on his first game as a professional he's playing in Ottawa he scores five goals no rookie and his first game in the history of the NHL scored five goals and they're all everybody's talking about him and he comes out for the interview and his I don't understand why you're happy we lost in overtime they lost six to five and the guy that scored I screwed up I cost my team the game and he walked out and at that point we wanted to make him prime minister nineteen year old kid ah yeah but they're gonna break my heart this is like like being a Jets fan alright so there's the evolution I think you should be doing this I think you should be here you're 8,000 to 9,000 feet right and you know you want to be Net Zero the best way to be Net Zero is to reduce the size of your renewables right you go as far as you can on conservation and then the last bit you throw on the renewables and the general ratio that I've been playing with over the last 30 40 years is you know 75 25 there you go 75% of the way with conservation and the last 25% you go with your renewables I never had it's just my opinion and I'm always right except when I'm not [Music] well alright then you're gonna have to compromise you're not in the NetZero business okay y'all don't understand it's expensive to build Net Zero who will get a tax credit well the money has to come from somewhere right now if we were smart we wouldn't be subsidizing solar panels we'd be subsidizing conservation I've done a bunch of them in my career and and and and and we find that okay we did a took a 1910 Sears kid house and in Concord Massachusetts and we reduced the utility bill from $800 a month to $75 a month and the idea is that that money that we saved could have paid for the energy conservation but I couldn't finance it now I'm rich we just wrote a check but I could subsidize a piece of PV array where the tax credit that's insane they're not even made here you know you should subsidize the work locally the people doing the work locally so we have a financing issue we can actually make it work but you know they're the democrats are the republicans aren't taking my calls right now so I asked Putin to help me [Music] all right that's a wall all right this is a calculation that I never want you to make but everybody in the world wants you to make it so I want you to know why you should not have to make it by actually making it what's called the dew point calculation and so if it's 70 degrees fahrenheit inside and zero degrees outside that black line is the thermal gradient through the wall everybody with me on that and it's it's idealized it's just you know it's a first-order approximation meaning it's within ten percent okay give me a break if you're within 10 percent declare victory right so let's say I've humidified the interior of my building to 50 percent relative humidity and at 70 degrees Fahrenheit and then zero degrees Fahrenheit outside first of all that's a colossal insane stupid thing to do that would mean that would be a hospital or an art gallery right dumb so if I take 50 percent relative humidity air at 70 degrees Fahrenheit and I cooled it down what happens to the relative humidity it goes up right and at some point it gets to a hundred percent we call that the dew point well the dew point temperature for a 70 degree fahrenheit air at 50% relative humidity is 49 degrees I know this because I have no life using joe math that's around 50 degrees so in the middle of the wall it would be what 35 degrees right it's zero and what so 50 degrees would be right here and I cleverly put in a dashed line right there because I got ya and so the dew point is that dot that's where condensation should occur but in all of the walls and all of the gin joints I've been in throughout the world I'm channeling Casablanca which was the greatest movie of all time I've never seen condensation there and in fact it's physically impossible for it to happen because when you have condensation it's a change in phase and then a change in phase and the enormous amount of energy is released okay so if I have one pound of water at 50 degrees Fahrenheit and I want to warm it up one Fahrenheit degree or cool it down one Fahrenheit degree I need to add or remove one British thermal unit so one BTU is the energy necessary to change one pound of water one Fahrenheit degree now if I have water in the liquid phase at 32 degrees and I want to convert it to ice in the solid phase at 32 degrees I have to remove over a thousand BTUs [Music] well if I have one pound of water in the vapor form and I want to convert it to one pound of water in the liquid form I have to remove over a thousand BTUs you could like look this up in something called a book they're found in places called libraries but they're very old books and so you have to ask a librarian and that involves a social interaction which is why you youngsters know nothing about this there isn't enough thermal mass in fiberglass or cellulose fibres to handle the change in phase energy what you need for condensation is a surface a condensing surface with sufficient thermal mass to handle this change in phase we call that a condensing surface so the first condensing surface is the backside of the sheathing so when somebody says where is the dew point location I don't have to do a calculation it's always going to be where on the backside of the sheathing [Music] I have a climate simulator and I like to screw with the youngsters at the University I don't call I don't view it as harassment I view it as education so hey dr. Joe you want us to crank it up to 70 degrees Fahrenheit 50 percent relative humidity on the other side how cold do you want to go well can you go to minus 40 well yeah so what's special about minus 40 both scales cross at minus 40 minus 40 F is minus 40 see we call it minus 40 F Seaver cold and the dew point is right freakin here but where's all the frost Wow magic this is a physics book never mind the first condensing surface in old buildings was the inside pane of glass because the glass was shitty and that saved old buildings you could never have more than 20 degrees 20 percent to 25 percent relative humidity in a cold climate with a single pane of glass because all the water would condense on the window save the wall yeah then what happened we had storm windows and then double glazing the window industry made better windows bastards so the condensing surface move from the glass to the wall cavity right so what do we do Oh where's the first condensing surface and a vented attic the dew point is in the middle of the fluffy stuff but it condenses on the underside of the sheathing and then drips down right yes Joe well yeah man you're gonna see something from Breckenridge shortly and you're gonna say well I can't believe anybody did that so the nails get the frost first followed by the sheathing the rafters see nothing because they're one or two degrees warmer and a one or two degree temperature difference is enough to completely change the moisture distribution in the system what typically fails is your shingle nail holding capacity so as you get moisture damage your shingles blow off because the nails aren't they've lost withdrawal strength right so they said okay I think I deleted that one of the nevermind so the way you ought to look at a wall as you plot the outside temperature in your location over the course of a year and that's that sinusoidal AK curvy thing now monthly averages are okay you don't have to do hourly you know hourly would be you don't care just averages this drives structural engineers crazy because structural engineers are interested in peak loads moisture engineering is always decided on average loads really with me on this now when you look at design temperatures in ASHRAE they're designing for the sizing you're heating in your air-conditioning system it has nothing to do with your wall design or your roof designer Jim it has nothing to do with the wall in the roof design so we do monthly averages and then we say well okay this curve is for my hometown of Toronto and basically if momma kept the relative humidity below 20% during the coldest part of the year we never had any damage in the wall but if I humidify it to 35% I'm screwed right well not really if this was plywood with tire paper and an air gap plywood breeze but when I change it to OSB OSB doesn't breathe plywood is 15 perms when it gets wet OSB is 3 [Music] so what can we do well we can warm up the condensing surface by insulating to the outside so the curve is here so I can now humidify to 35% because I've increased the temperature of the condensing surface already see how that's done and so each location has its own curve and you can do your own calculation I don't want to do that well okay we we did it for you we put it in a table in the code that tells you the percentage of the thermal insulation you need on the outside you know there's what are what percentage is the thermal resistance of the sweater nobody with me on that so let's go back and say that the r-value of the blue layer compared to the pink layer varies from place to place to place based on the curve I'm going to need more in Basalt than I need in Denver right now what if I don't want to put the stuff on the outside well you could use clothes sell spray foam on the inside to keep that but to you keep the same ratio everybody with me on this then I can lay it on on the side and call it a roof or a flat roof standing it up so wall laying on its side or a roof standing up gives you the same situation the least risky was to put all of the insulation on the top your ultimate cold roof the trouble is is that when the snow load goes above 50 pounds of square foot I need an air gap on the top to disconnect the thermal resistance of the snow layer I could do it with spray foam underneath except where I have lots of snow or I could do a mix of rigid insulation on the top and fluffy stuff underneath or spray foam underneath with fluffy stuff our clothes sell first and open sell the guy I've got all of these possibilities but the ratio is what's key and that's determined by your location now vented addicts it's hard to argue with a vented addict if this ceiling is airtight this works in basalt this works in aspen hell this works in Miami so how do we get ice damming well when we don't make the ceiling airtight energy from the house gets there and then we couple that with the thermal resistance of the snow on the top now what happens with the classic ice dam is that the snow layer melts and the water is wikked up into the snow we don't get a nice lens directly on the shingle so we have a gap it freezes solid at the overhang hence weak that's where the damming takes place and then the water backs up that's why we have snow melt only at the edge we don't need it in the field of the roof if you're backcountry skiing and you're worried about the risk of avalanches right the change in phase when you have a temperature differential and some melting and some freezing this wicking is a big deal right and never mind and you saw this already Oh SB doesn't come that color when it's new this is not the answer this is what they did in in Breckenridge let's warm up all the nails by putting foam on them this is a clearly a man with too much time on his hands this is New England where we want the snow to slide off the edge because that's if the snow isn't there that's why we don't have the ice damming right we used to do this or we do it and the way we do it here by doing it this way this is on Main Street in Aspen of course but that's okay this is green electricity right this is an indication that you don't know what you're doing you don't need snowmelt to control ice damming [Music] so let's you know cover the whole damn roof with a membrane okay I like this by the way it handles one of the negative aspects of ice to having the water leakage but these dams get very heavy and very big and if they fall off and you're under them you die or they'll take away your your deck or something and we shouldn't have one in the first place this is the thermal resistance of snow it's from the US Army cold regions research engineering lab in Hanover New Hampshire from the 60s this is an R 70 unvented compact roof in Burlington Vermont was a huge freakin ice dam I'm here to tell you that just going to a high level of insulation and air tightness won't keep you out of trouble where you have large amounts of snow just say what it doesn't matter why would it well it could slide up off quicker but most of the times we put a snow fence there to prevent that from happening right [Music] totally totally agree with that but if it's vented from underneath the problem is dramatically reduced let me show you a couple of tricks I'm 5 minutes over my time limit but we started 5 minutes late so I'm going to take the time all right so this is my go-to cold climate roof with a lot of snow a vented airspace over an unvented lower roof so as I have a none vented lower roof and I over I put an over a vented over roof over the top of it this is where the Sun beats down and might be 20 degrees Fahrenheit outside and it's sunny what's the temperature of the siding about 50 degrees so that's siding warms up the air and the air is warmed up and goes and then causes the ice damp to occur because of the solar heated wall this is worse with darker cladding right and so we've learned in cold climates that I want to put a layer of rigid insulation on the underside of the overhang and then put the vent in at the fascia so I'm not venting the roof with warm air I'm venting the roof with cold air this is the sundeck and all of the snow keeps sliding off and so it makes the front unusable except when it freezes solid then they have to hire Australian ski bums to chop it off why Australian well they'll do stuff rats won't do I mean look at this this but it one it's greeny weenie award they've had to the malls they patted themselves on the back we did a great freaking job yeah so what we've been doing is we've been putting vented over roofs over the top of the poorly vented Roos underneath you see what we're doing there this is original and it doesn't work we've added a vantage roof over the top [Music] at the ridge we close the original ridge vent area with a vapor open material so we don't want air but we want vapor to be able to get in so it's a vapor diffusion port right I'm not trapping moisture in the roof it's able to get out at the ridge because that red line is vapor permeable really with me on this ah well how does we know that the moisture is gonna get get there because moisture is more buoyant than dry air as you add moisture to air you lure you lower its molecular weight you lower its density and then I've put my Vantage over roof over the top of that this is the proposed fix for the Sun Deck I just wanted to trade them for lockers give me two lockers at the base of the gondola and I'll give you the design once I give it to him anyway it published it mostly to embarrass them so the idea is to spray on foam underneath to prevent the heat from the Sun then put a vented over roof but they have to vent it in the wall because of all of the snow we have to get the air out above the thickness of the snow right yes Joe as well it's in next year's budget okay this is in Big Sky Montana most of the older buildings are having vantage over us put over them this is uh quite beautiful right this is a retrofit you can see the big dance over the top okay this is in in Beaver Creek we've got we got a divan turnover roof with fascia offset and then all the ridge is covered with snow then we ask these things called cupola to allow the air out above the snow I mean I get wrote a report up called I titled it cupola for Coppola I ended up with a dead horse head in my bed all right I'm not going to talk about shallow yes sir know that with a flat roof you basically live with the fact that you're going to have all that snow you're going to probably have ice what you want to do is you want to make sure that you've got heated drains the question was is there a tipping point or a magic number from a slow perspective of ending the space if it's I think you should always vent something that's more than you know 212 and I pulled that number out of my butt all right but it you know I'm gonna jump ahead and show you what you can do if you are crazy you could instead of digging down four feet for frost protection you can insulate horizontally four feet but you have to protect this skirt from being from absorbing water by capillarity and well like extruded polystyrene well you could do it with mineral wool this is a famous architect who I'm married to doing a load test on mineral wool so we scraped the dirt filter fabric stones mineral and a waffle pattern so that when we cast the slab it's stiff right plastic vapor barrier concrete and the mineral little skirt concrete perimeter to protect the mineral wall we built the wall you get the idea so that's you can do this with foam you can do this with mineral wool you could do this with with whatever and instead of digging down you insulate horizontally so they called this the Swedish foundation and I'll because it was developed in the 1960s at the Army Corps of Engineers cold regions engineering lab in Hanover New Hampshire Wayne Tobias ins team did that work and nobody in the united states cared at the same time eli robe in ski who was actually a syrian immigrant into canada the University of Toronto was doing exactly the same thing a bunch of Swedish builders you know God lost looking for animal house at Dartmouth [Music] ended up in Hanover and said wow this is awesome of course they said that in Swedish and we went back to Sweden and they started doing shallow frost protected foundations and a bunch of builders from the United States on an NH P you know junket went to Sweden and said wow this is freaking fabulous the Swedish foundation system so the Swedish foundation system is really an American foundation system but apparently we trusted the Swedes better as all marketing this gives you the frost depth which tells you how wide the foundation should be one of the principles we learned in building the alaska highway last foresaw the alaska highway isn't in alaska so the highway to alaska goes through canada and what happened was is that the japanese invaded the united states they landed in the Aleutian Islands and they were island hopping and people were very worried that they're gonna invade Chicago through Alaska through Canada and so we built a highway to defend Alaska my father being my father a fighter pilot in Europe it was stupid there's no highway why should we build a frickin highway they can't get to us unless we build the highway don't build the damn Highway see dad right by the way I've become him anyway what ended up happening was is that the 10th Mountain Division and the Devil's Brigade which was a great movie with William Holden and Cliff Robertson kicked them out and then they came and they fought the Germans in Italy and they came back and they founded the ski industry in the United States that's why you've got those statues of those soldiers carrying guns while they're skiing it all happened here Cape Cap hail now the reason I know about that is because it was staffed with volunteers organized by the Ski Patrol and I was a ski patroller for 20 years and so we know that story so yeah anyway we learned that frost heaves in the direction of heat loss so at the bridge abutments it was a nightmare and so the idea was just add some insulation there and you've changed the direction of the force and now you don't have to make the bridge is strong so by insulating you can change the direction of the loads this is a big deal if you were to have your basement colder than the ground the ground will heave into your basement but if your basement is only five degrees warmer than the ground you never get frost heave do you follow that's why you say well look you're gonna go away for the winter leave your furnace on set it at 45 degrees you're never gonna have frost heave do you follow yes Joe I guess that's why it happens now in an uninsulated and heated basement these are your isotherms this is the way the temperature profile of the ground looks and notice that the snow is less thick at the house perimeter because of the heat loss you might think this is a simple cartoon of it this is just very sophisticated well when we insulate up the wazoo on the inside of these we then change dramatically the isotherms and the worry is is that if the soil is wet and it freezes when it heaves it'll lift the building off its foundation do you follow yes Joe all right so we can change the direction of the heat flow by using horizontal insulation that way we get rid of the risk now if this is a concrete wall and one piece there's not much of a risk if it's a block wall or a rubble wall there is a risk right yes Joe there is a risk now if you just get rid of the water with a freedom drain French drain okay French for you know freedom price all right it you don't need very much in other words you can just dig down you know two feet shovel with put in a perimeter drain cap it with a paver or you know you prevent water from saturating the ground besides your foundation you never have a risk duty follow you need water and shitty drainage to cause trouble or you can change the temperature to control things now a lot of these rubble foundations are so porous that the rubble itself becomes the drain do a lot of work in New England this should have been trashed a long time ago how come well the ground isn't wet because we're draining it into the building alright last couple images this is the old stuff from the Chicago from the Chicago World's Fair in 1870 and then this is our version of advance framing today 24 inch centers single plates two stud corners no Jackson no cripples headers only on load-bearing walls two stud corners the clips connector plate across Ridge you have a slice if you want this place you want to push the header if you have one away from the drywall because the header moves when it does it'll crack the gypsum board the best way to keep trip support from not cracking just don't attach it to wood so push the wood away [Music] this is beautiful isn't it everything lines up no Jax no cripples you don't need him to stud corners clips interior walls just a little plate shear only need them at the corners so you you know you take your inch and a half rigid insulation and reduce it to an inch thick at the corner because the half an inch will be your shear wall [Music] small gap to back ventilate your trim in your siding with strips tape the joints you got yourself a very low-cost high performance building all right I'm done [Applause] this is the part where we play stump the chump and I'm the chump and you're you get to ask the questions well it doesn't have to be film it could be mineral it could be rock well so well well know if I have rock well I'll have a water and air control layer behind it so I don't care if it penetrates the rock well as long as it doesn't get past the rock well water control layer interface right this is blue board you can just tape the joints of the blue board now we do that with low rise when we start getting above two or three floors I put a draining layer behind the blue board supported by my sheathing so if I'm if I'm if I'm doing a five storey apartment building if I have say gypsum board sheathing you know dance class gold I'll probably put a water and air control membrane on that I usually use the fluid applied and then I put the mineral wool over that and I get drainage because mineral wool drains right you had a question sir no I answered it I'm always afraid when I ask you Jim but go for it [Music] okay the question was HRVs versus ER V's in this climate if you are ventilating at a high ventilation rate you're going to need to humidify and provide an ERV if you aren't stupid and you ignore ASHRAE 62 - and you ventilate at the IMC or the IRC rate that I just passed yay chances are you can do it with an HRV and not need humidification so if you the point is is that the higher the ventilation rate the more moisture removal the more moisture removal the more uncomfortable and you get to a point where you know things become so uncomfortable you have to add a humidifier well if you're adding a humidifier and you're ventilating at a high rate it's kind of dumb to not capture that moisture in an energy recovery ventilator captures that moisture if you're ventilating at a lower rate you're not going to have to go to a lot of humidification or excess of humidification and an HRV is less expensive and more efficient that's my short answer I want you to know there's absolutely no consensus to that statement but I am of course right yes sir I can't you speak up well the the condensation can if I insulate on the outside with continuous insulation do I have a condensation concern does it go away and the answer is it will only go away if I get the enough insulation on the outside so that the ratio is appropriate to the climate zone now that the ratio is in the code that are in that that the ratios that are given in the code you have to read the weasel words that go with it it's for non special use occupancies that means residential occupancy or commercial occupancy it doesn't mean a humidified hospital or art gallery or museum it certainly wouldn't work for an indoor swimming pool in situations like that we would never insulate on the interior cavity we would put all of the insulation on the exterior we wouldn't even do it we wouldn't even do it acoustically we'd handle the acoustics with panels and other sound absorbing devices so a swimming pool you don't have a ratio the ratio is a hundred percent is on the outside an art-gallery a hundred percent on the outside but residential because the humidity's are should be lower residential you should be you know 25 to 35 percent tops the ratio works for you I think we got time for one more before I get the hook from yes sir [Music] [Music] okay let's say I had a 2x6 wall with OSB on it and I decided to spray the cavity on the inside with two-pound density polyurethane foam that is there's no vapor absorption of that at all well no no just I'm not setting it up right then I'm let's say I now put oil faced Isis saying rate on the outside so I got full-face Isis saying rate I got OSB and I got spray foam if that OSB gets wet I'm doomed now what are the odds that it's going to get wet most Clint Eastwood's right Clint Eastwood thermodynamics do you feel lucky punk will do it I believe that it will get wet so I provide a small gap between the foil faced isolate and the OSB normally the OSB has got a water control layer on or an air control layer and then I put a gap how big of a gap well about a sixteenth of an inch of a gap why well we know that it works how do we know that it works well we built a lot of buildings and stress to see if it works doesn't that gap reduce some of the thermal resistance of the foil faced Isis an urate and the answer is yes it does I lose three to five percent of only the continuous insulation now that's less than the thermal bridging I get from the mechanical attachment of the cladding through the insulation anyway so I'm always going to provide some drying with some what we call it hydric redistribution as a big word that means that I want the to move around all right but I'm willing to give up some thermal performance of the continuous insulation to make it work if I didn't use well faced Estes and right if I used rock wool or mineral wool I wouldn't need the gap [Music] all right okay one more I can't resist [Music] did they are well normally they're on nor normally we're framing on 24 inch centers so I've got a one by four twenty four inches apart and my screws are usually maybe twelve inches apart and that's and I use stainless steel of screws because they're you know one half the thermal conductivity of carbon steel it's really trivial now most of the thermal bridging of the cladding is gone because it's attached only to the wood furring right well no it the the screw isn't going to condense because it's buried and the wood stud right okay i'm not can i'm only attaching my cladding to the furring strips and the furring the only conductivity i have is the screw through from the furring strip into the stud all right I'm not getting any condensation from the inside because it's buried in wood right I'm I'm I'm it's in it's in the wood stud itself I it's not a it's not an issue now the trouble is is you have to make sure that you get the freakin screw and the stud because if you don't what you're screwed [Music] all right I think I got the hook thank you [Music] [Music] you [Music]

Channel: GrassRoots Community Network

Views: 86,249

Keywords: Aspen, Colorado, building science, civil engineer, perfect wall, Lstiburek, forensic engineer, building investigator, grassroots tv, building moisture control, mountain climate, rain penetration, building durability, construction technology, microbial contamination, building code, industry standards, rain air vapor thermal, wall street journal

Id: iHBYvqr2_io

Length: 103min 4sec (6184 seconds)

Published: Sun Feb 17 2019