Building a BETTER attic - Unvented + Conditioned attics 101

you know most addicts in america look like this where you've got a roof line you've got some vents to the outside and you've got some fluffy stuff on top of the ceiling drywall now i'm down here in texas which means i don't have a basement so all the ducks typically are also up here in this space now this space in the summertime could get pretty dang hot pretty dang hot [Music] like 120 130 maybe even more degrees and the only thing separating in this space from below is a little sheet of drywall and this fluffy insulation this is a vented or an unconditioned attic we've been building this way for decades and this is a dumb way to build we've got better technology we've got better ways to build on the build show today i'm going to take you to two houses one is mine under construction and another one that i'm building for our client where we have built totally differently from this where we're building conditioned addicts that are unvented today's build show all about addicts let's get going hey guys do you know my friend ken allison from idi insulation ken this is actually my house and this is what we refer to as building science nerds as a conditioned or an unvented addict talk to me about what you're seeing here what i see mostly is just a beautifully done attic the idea of using rockwool up here as your insulation for this attic the sound is tremendous it's it's really beautiful and i love the way you did the framing but what's nice is this stuff staying in place you're going to have just a beautiful insulation package up here and what i don't feel is all of the humidity yeah that's right we're totally isolated from the outside cannon so much so that it's actually raining outside and i've got a metal roof on you can't hear anything in here it's super quiet and this will be and my air conditioning system's not on yet we're still under construction this will basically be the same temperature as the rest of the house it might be because of you know the stack effect or heat rising this might be a couple degrees hotter but if my thermostat below here is set at 72 i don't expect it to be more than like 75 up here the this is really a great job and i know that they've talked about the need to have a vapor valve or something like that on top of something yeah diffusion poured on top of some of these that's why i mentioned my first thought is i'm not really feeling the humidity up here this is done so well and there's so little outside air coming in like you said it's raining yep and this feels nice and dry yeah it feels good in here this is a great attic and the cool part is this we don't need to put a thermal barrier over it so this is a very workable attic you've got great storage in it this is much better than a traditional build and the other thing that you're going to notice as you look into this attic can is that all my ductwork is below the insulation so the ductwork is in the conditioned envelope of the house it's in this unvented attic space there's no gable vents there's no ridge vents going on here any venting you might see in the outside is strictly venting the roof between the the metal roof and the roof deck underneath it it's not into this space everything's fully closed and sealed off i've got a very airtight house all my air conditioning lives in the same air space as i do means my ducks aren't going to break down it means my house is in my attic in particular is free of bugs and pests and rodents and uh the mouse poop and rat droppings you see in attics all over texas none of that's going to happen in this space i love that and to look at your ductwork this is stretched beautifully tight so therefore you're not getting any loss there and if this were a traditional attic like the ones that we normally see you would have heat flow heat's going to go from hot to cold you would have heat flow from here going down into the house taking dust and all of that kind of stuff with it you're not going to have any of that yep for sure now ken you and i have been working on another project with a different type of insulation but still a conditioned unvented attic let's meet you guys over another project all right ken another house of mine under construction my company's building this for some clients they wanted some attic storage space and when we designed this house with the architect we designed this beautiful space one story house great amount of attic up here and we use closed cell foam over here now we've got four inches at the roof deck here sprayed right on and that's the beauty of closed cell foam is it sticks i thought about using rockwool for this house but there's a lot of complications on this project and i don't have a thick exterior foam on the walls although i do have four inches of polyiso on this roof on the top side of the roof but the nice thing of this spray foam you can see as you look back here no matter what way the roof cuts it's really easy the spray foam contractor just sprays it and it sticks right to the roof deck this also closed cells so it's a really high r value per inch it's around r7 per inch 7.1 so we're like r50 basically between this interior foam and the four inches i've got on the outside but talk to me ken about what builders need to know or homeowners for that right reason about spray foam in an attic that you can have access to or that there could be storage in the big thing about having foam like this anywhere whether it's a shop a barn or a house is foam is liquefied plastic and cellular plastic can have fire go through it now there's two main differences in foams you have thermal form and thermal set so a thermal form foam think of you know your white pink or blue your your styrofoam type foams okay those foams will actually when you heat them up to a certain temperature they'll bend somewhere around 170 200 degrees they'll bend they'll form they'll shape but somewhere over 300 degrees they go up and they will actually propagate fire that's the legal term they'll take fire from one location to another okay spray foams on the other hand are thermal set foams so these will not uh drip and rain fire they'll only shrink in char so one thing we want to do is take a look at that compared to when we put the coating on it because the coating is there the code sees all phones the same no we haven't talked about the coding what are you talking about by the coding if the code official believes there's a reasonable expectation of storage or auxiliary living or using the space foam always has to be separated from people with a thermal barrier okay gotcha so in this case when we look at this unfortunately a lot of the you know where do people keep their christmas ornaments up in the attic well if your attic was 70 degrees year-round instead of 170 in texas where would you put all your stuff up here okay so that means we have to have a thermal barrier and unfortunately there's just a lot of builds that happened over the years or sheds or agricultural buildings that never got coated the coating that is on this you you can notice that all of this does not look like the standard foam the standard foam is going to be yellow yep it's got a whitish color to it right this is several mils of a white intumescent paint so it is a paint that basically my choice is i can have a 15 minute thermal barrier which would be a drywall or i can go with a coating that is compliant with a 15 minute test okay so this dc 315 actually complies with that testing there's a lot of solids in this bucket and so it's very thick but if you ever played with the snakes on the 4th of july the little graphite pellets same type of stuff in here those pellets will expand once you light them on fire this will do exactly the same thing you know what would be fun ken i saw you've got a couple of uh surfboards of foam that were sprayed as testers why don't we light one of those on fire and see how it turns and then let's spray paint one with this dc 315 and let's see how that burns i'm all in let's cut to that all right guys a little driveway dumpster fire test we've got an uncoated piece of spray foam here if that catches fire we're going to show you what that looks like and then we're going to show you that same foam that's got this dc 315 into messed paint coating on it which is what we're using on the attic so that being said let me start the gopros and ken let's light up the torch as you can tell when we do fire testing this will put up a lot of smoke one thing i want you to notice matt though foam is one of the most tested products in the industry this is actually going out on its own when i remove the flame the foam goes out but when you saw that amount of smoke we can't have that kind of smoke inside someone's house smoke development's the biggest deal so the coated stuff we shouldn't have the same results all right now this is the same test with dc 315 on there which is an intumescent paint let's see if we're getting any smoke out of that dc 315 so the next thing i want to make sure you see here is this char we're developing this char is what is happening with the paint when we talked about it in the attic so that char that we're developing you notice we don't develop that over here this will only shrink in char but it totally degrades the foam so what i want to do is i'm going to knock some of this char off let's do it again let's do it again next thing i want to show you matt so not only did it do it twice where i damaged it by putting this in the flame got behind there but it still did not completely change the foam here we didn't burn through the foam but have we put it on it that long we certainly would have yeah take a look at this nothing on the back feel that not even hot yeah that's crazy not up so that intumescent paint is actually kind of expanding and blowing up to protect that surface up to two thousand percent in fact what was happening when you got close if you think of the little pellets on the fourth of july that they call snakes and you light those and they grow and kids will almost get their finger real close to them this as it expands produces carbon dioxide which is a cold gas so it's taking oxygen it's pushing the flame away from the foam and it's cooling the room down incredible technology yeah that's a good safeguard for an attic that's going to have storage and that's going to meet code to be approved for attic use and you're going to also want to double check your icces reports to show which one of those is approved and also the thickness correct ken yes you cannot just put any intumescent coating over any foam in order to be approved you have to use a coating that's actually matched to that foam and you have to put it on at a thickness that is approved the thickness we've got on here we're running at 115 square feet per gallon there are others in the industry that are all all the way down into the 60s per square foot wow so sometimes you have to put on double this right but in this case we've got the one that covers the greatest amount of territory in the industry and that's why we use it that's pretty cool all right let's get back to the attic okay so that means we have to have a thermal barrier and unfortunately there's just a lot of builds that happened over the years or sheds or agricultural buildings that never got coated and they just have foam and you saw what happened to the foam by itself so the great part is this is not that expensive it's certainly a lot easier than putting drywall over this entire attic in order to protect you from the foam and a whole lot less uh money involved too now the way that you figure out whether you need this though is there's uh going to be an icces report you have so it's going to be available through the manufacturer's website and that's going to tell you if this foam is going to be in this type of environment what coding is necessary to protect it right yes so there's icces is one of the approving organizations or one of the organizations that reads all of your testing these compliance reports once you read them you can go right down it's usually section four will tell you whether or not they're approved without an ignition barrier meaning we're not doing any storage or what it takes for them to comply as you know thermal barrier protection in that attic or in that space so you have to make sure that the coating you're using is approved with that specific foam long as you got that you're golden and so this dc 315 would this actually be called out by name in some of those reports or not necessarily dc 315 actually on their website has a matrix that shows you all of the phones they're compliant with they're actually the most tested they have i believe over 200 different compliance tests that they list on there very cool so i could be wrong on the number but it is far and away the most tested in the industry okay good deal so guys we got into the weeds a little bit on conditioned unvented addicts but really what the point that ken and i wanted to show you was that with a little bit of forethought and not necessarily any particular product we showed you two different versions of it you can change your attic from the typical vented attic that you saw earlier to an attic like this now these are both new construction jobs it's certainly easier to do it new construction but that could be a retrofit or remodel situation as well if you're doing that there's a little bit more work there's there's more thought to go into how to do it but on a house like this now that we've got this spray foam in place we've got the dc 315 in the ductwork is going to live in the air conditioned space this is a beautiful attic and just like you saw in the other house don't forget about your fresh air when you build a really tight envelope a really tight house with this non-vented conditioned attic you've got to think about fresh air one of those pipes right there is to the outside that's fresh air it's going to get connected to the zender one of them is an exhaust pipe that's an erv and then all these tubes are tubes that are either supply fresh air or exhaust air out of the house because it's a balanced system i got a great video i'll put in the link in the description about the zender at my house and how it works and how it operates but ken thank you so much for joining me on today's video idi is a fantastic distributor with all kinds of different insulation supplies and you know ken and i you can only imagine how much we've nerded out of the years over insulation quite a bit guys if you're not currently a subscriber we've got new content here at the build show every tuesday and every friday hit that subscribe button otherwise follow me on twitter instagram we'll see you next time on the build show [Music] you

Channel: Matt Risinger

Views: 865,325

Rating: 4.8846002 out of 5

Keywords: Matt Risinger, Build Show Network, The Build Show, Build

Id: XjI8HyUqe4w

Length: 16min 54sec (1014 seconds)

Published: Fri Jul 23 2021