3 Spray Foam Problems (You Will Run Into)








How do y'all, it's Jordan Smith, there's five things that this wall behind me is doing right. Now, it's keeping the roof off of my head. It is keeping out moisture, it is keeping out air, it is controlling heat and it is controlling vapor drive. Today, I'm going to talk about this product here, spray foam and its ability to keep out both heat and air. So everybody knows that spray foam is a good insulator. It has a high r-value if installed correctly, it can also be a good air barrier. There'S a few things that you need to look for to make sure that both of those are done as well as they could be on a Spray insulation job. So, first you want to make sure that your required thickness for your insulation value is actually there. The spray foam doesn't have to be full cavity depth, meaning you don't have to overfill the cavity and then come shave it back off, especially if you're using a thicker stud and your R values are lower. Maybe you only need say, four inches of insulation and you've got a two by six and so you'll have some insulation. That is just this bubbly texture on the front and it's not shaved off the problem with a under filled cavity. Even if it's to the right thickness is it's hard to tell if there's any spots that are under filled, if you went all the way to full cavity thickness and then shaved it, even though you're wasting that time and that labor and the material that you're putting On the floor, it's easy to check to make sure that it is all uniform thickness in this house. I'Ve seen several places where it's actually under filled, where there's not enough insulation and we're gon na have to come in and bring that back to full thickness. The second thing that this spray foam insulation should do is keep air from infiltrating into the house. At least that was the case in their original design. This is a house that we have taken over mid construction. It was all the way to sheetrock and they were putting cabinets on the wall. We'Ve ripped off all the exterior cladding and all the interior and are redoing it, and we found several places where this spray foam is not only under filled but also pulling away from the studs. And so, if that spray foam is pulling away from the studs in the same place, that you have a seam in your sheathing and the exterior sheathing is not taped or doesn't have a fully applied membrane of some sort, keeping out the air, then your air will Leak right through that hole in the the gap in the sheathing and then right through the gap between your stud and your spray foam. I called my spray foam buddy up and I said hey what causes that I'm doing this video. What causes it to pull away from the studs? He said man, it's so hard to tell you in a quick phone call without actually being there, because there's all kinds of parameters, there's the heat of or the temperature of, the spray foam as it's coming out of the guns too hot, and you have a problem Too cold and you have a problem if the studs are wet. You'Ll have a problem. If the humidity in the air is not exactly right and the operators not cognizant of it, you can have a problem. So there's a ton of variables that the operator has to be aware of when he's applying this, to make sure that he is doing the best possible job now, even if you get a really good operator - and they put it in really well - and your whole wall Is airtight because you've done everything right? You still have this issue here at the bottom plate now in this house. What they've done is they've, come with this foam, this fire-rated foam and have sealed the bottom plate this stuff. I don't like for this very reason. I can come up here and chip, it chip it away all day long with my finger now. The idea is, it goes in and then you're finished floor goes in and everything is good and everybody's happy. The reality is that we've got a lot more construction left here and that is going to be chipped up all over the place and then over time, as this bottom plate expands and contracts and as our concrete expands and contracts at different rates. That interface is not going to hold up with that spray foam. It just doesn't have the adhesion that we need, so I much prefer a either a caulking process or I'll show you what we did here with the poly Guard stuff once we get outside so another place that spray foam is weak on air sealing is where the Wall and the roof assemblies meet I'm outside the original house right now, we've added this on, but it's a great place to look up and see where the original rafters exited the house. We had an exterior wall coming up here. Meeting this roof and they've put up OSB blocking, and then they sprayed it from the inside with spray foam for the air sealing. The problem is every time that they have the scabbed on stud tying the rafter into the load, supporting stud there's about a half inch to quarter inch air gap between every single one of those and that's a huge place for air to leak in so spray foam Is prone to air leakage? What do you do? Well, we don't depend on spray foam for our air sealing we've done it in the past, and we've had good numbers that spray foam will give you numbers that hit code. We have to be at least three ACH here in Austin down in Houston, Thera, five ACH. So, if you're, he trying to hit those types of numbers, spray foam will get you where you're going. But if you're trying to get really low - let's say passive, which is 0.6 ACH, then you've got to do a different strategy. I'M going to take you outside and show you what we're doing on this house for both our moisture and our air control. So if spray foam is not the panacea of air sealing that we might have thought it was, what do we do well, in this case, we're actually getting our air sealing from the outside of the wall with a luma. This is Polly walls, Illuma flash and it's a fully adhered WRB that is stuck to our OSB and seals all of the seams in between the different panels. So we don't get air infiltration through there. Now some different products that are applied with just say, cap, head staples, will do okay on infiltration because they will get sucked in tight between those when the airs leaking in between those seams. The fabric will get pulled in tight and will stop that air leak somewhat. But on exfiltration you'll actually create a balloon, you're actually blowing that WRB away from your wall. So I really like the fully adhered membranes for air sealing now remember: the wall coming down to the foundation is another very weak spot for air infiltration, because on the inside remember, I said I didn't like the spray foam between the bottom plate and the foundation. It chips away and if that chips way, then air can just leak right through that scene. What we do is we use blue barriers, joint filler, and this is actually an adhesive as well as a filler, so it fills the gap, but it also sticks tenaciously to both the concrete and the bottom plate preventing any air from coming up in there. We did that before we put on the poly wall, Illuma flesh, and then we illumine over Neath that seam, so any water that gets back here runs and is able to drain away on the foundation thanks. So much for watching comment below with your favorite air-sealing tips and tricks subscribe if we've earned it go, follow us over at Instagram and we'll see you next time on the build show. So insulation works by keeping the air inside of it from being able to move back and forth, there's a really good insulator. So I don't know what the r-value of a foam cup is, but they just threw their. They just threw this McDonald's cup. Sorry chuckle Bell cup right in the wall and then thumbed over it. So I think it's got a pretty good insulation value.





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