Achieving Higher Performance with Batt Insulation, Roxul

I'm over at my buddy's garage we're gonna be doing a few things to improve this place we're gonna be adding insulation some sheathing on the walls [Applause] [Music] for insulation we chose to go with the rockwool this is meant for two by sixes 16 on center which is what we have this three quarter inch AC plywood is the shelf material it's going to be the last item to go in place so I'm gonna move this out set it on some sleepers in the driveway and that way it's out of my way and I can get to the sheathing OSB which I'm gonna need first I move the material outside and it's stacked now in the order that I'm gonna need it I've moved all this stuff away from the walls and took a lot of things outside so at this point you just have to start looking for things that are in your way I'm doing the top four feet of the wall today and this block is from the roofers it was installed as part of their staging for outside I'm gonna take that down my buddy has some of these hooks up here I'm gonna unscrew those ones okay I've pulled every nail and block that was in the way in the top four feet of this wall this is a very typical framing detail you might see the framers put a two by six on each side of the corner and that's so that the drywallers have something fastened to and that's great for the drywallers it's difficult for me where I need to insulate this corner so what I'm gonna do is actually remove one of these studs this is the redundant one this one I don't want to move so the sheathing is fastened to this guy and I can look in and see that there's another stud running this direction which is why this is the redundant so I'm going to cut the nails that are going to be in the bottom and the top you see how this one is not fastened to the sheathing my theory is why would you want to spend any time or any money doing a job that's only going to work 50% because that's what you're giving up if you don't get these tiny details so a tiny percent of space missed contributes to a huge chunk of energy loss it's not a lineal scale with that corner vacuumed out you can clearly see where the stud sat and the nails that I cut with the reciprocating saw at this point you're probably saying it's got to be ready for installation right but wait there's more we want to air seal this cavity before we put the insulation in we're gonna be using rock wool batt insulation which is not an airtight product so we're gonna air seal the cavity before putting it in I'm gonna be using some siga Rhys on tape but you can use a lot of different types of flashing tapes and air sealing tapes that are out there and we can got my glove so that I won't get any splinters hopefully then you want to press that in when the framers built this they ripped this sheathing shy of the top plate so there's a big gap here a good quarter of an inch I have to make sure that I air seal that I'm not a fan of this detail I prefer when the framers go up and lap onto the top plates and that helps lock everything down don't forget to go ahead and air seal any holes leftover from staging after I have air sealed those sheathing joints which tape works really well for I'm now going to air seal the corners between the stud and the sheathing now for that tape is not the best product instead I'm gonna use a polyurethane caulking because it can really get into those corners now if any of you are thinking this is a lot of work it is it's a lot easier to air seal a structure from the outside my favorite way of air singing a structure is taping the sheathing joints on the exterior that then you don't have to do any of this caulking or the work on the inside it's a lot easier and if you want to check out an example of that I'll link in the description below to an air sealing video of how I built my garage where I tape the exterior joints as you can see I cocked the corners but that big gap at the top I used one part expanding foam one part expanding foam is better for a big crack here I just couldn't get the caulking gun in because this stud cavity was too narrow also wherever there's wires that exit foam those as well all the stud Bay's are air sealed they're prepped so now we can start putting the rock wall insulation into them both rock wool batts and fiberglass bats are both really horrific make sure you dress appropriately gloves goggles and a mask to protect myself as far as cutting the rock sole it doesn't compress the same way that fiberglass bats do so you don't want to use a small razor blade what I did is this morning I just picked up the cheapest one dollar knife I could it's just a kitchen knife you want to get something that's serrated a bread knife is really good the the long serrations better than these little serrations that are on this but plan on using it for one project and then tossing it out because it's gonna dull quick so push it up to the top compress this side and slide it to the rear notice I put my hand like this and I'm compressing it in and then with my fingers and bring it all the way to the rear but you're going for is full contact the bat needs to be all the way up against the sheathing and against the studs and all the way out to the front this stud cavity has a wire now that's going to prevent me from sliding the rock wall in easily so I'm gonna take the rock wool bat and I'm gonna put it against the wire first that I take the bat and I split the bat to go around this wire okay I'm making sure that it gets all the way up into the corner all the way to the very top when you measure the cavity you look down here we're at like 32 and three-eighths and you maybe I'll cut that one at 33 you want to cut it a little bit longer or a little bit wider than whatever it is so what I do is I just run this out to 33 and then I tend put my knife right on the edge and I can make a nick now I know where that is and I can just eyeball square because it doesn't matter to be perfect well I have the upper four feet of insulation in place and that's all the insulation that I'll be installing for this project and then my buddy's gonna take over from here down I'm gonna start with the sheathing to go here and in order to make the end of the sheathing line up I'm gonna cut off a little bit now that piece that I cut off I can reuse into this corner as my nailer I probably should have put this nailer in before but it's fine I'm putting it in now it's just I'm using screws from the outside whereas before I could have used some screws from the inside I pre drilled these screws so that I won't split off this last little bit of stud so I'm gonna put some glue on all the studs where this piece of sheathing is gonna lie and then it can make the front air seal so it doesn't have to be glue but that's what I got that's what I'm using it could also be acoustical sealant or coffee my buddy brought me in just for the upper four feet because I'm gonna be building some shelves up here now he's going to be continuing down the process when you go to take the next piece of OSB and you want to butt it up to this one this horizontal seam needs to be air sealed as well now that needs to be done with either taping it or what he might be doing in his case is he might be putting a bead of caulking on here before he butts the next one up to it then it has to be installed inside a six sided enclosed cavity so we enclosed the top the front back sides and the bottom those are your six sides now I haven't done the bottom yet like I said that's my buddy but you get the idea this is how a bat needs to be installed to make it work - it's rated our value see if wind blows through there it takes away all those trapped warm air pockets and you're paying for that insulation you want it to work even when it's windy outside even when the temperatures are extreme outside in order to make it do that it needs to be inside an airtight enclosure now that's different than say if this was dense pack cellulose like what I have in my home doesn't require a whole this but it still benefits from an exterior air barrier this was a lot of fun I hope you took something away the bat insulation needs to be inside a six sided enclosed cavity in order to achieve its rated R value all right hey thanks a lot for watching if you enjoy these videos please like subscribe comment and share

Channel: DavidPoz

Views: 161,930

Rating: 4.8463116 out of 5

Keywords: air tight, air sealing, caulking, construction adhesive, roxul, rock wool, bread knife, serrated knife, diy, insulating, insulation, batt insulation, batts, fiberglass, guide, how-to, garage, workshop

Id: i0GIl7kL_pQ

Length: 10min 27sec (627 seconds)

Published: Mon Jul 02 2018