In this on‑site DIY video, Curt Janzen explains why keeping moisture out of walls is essential and walks through the correct way to install batt insulation with a polyethylene vapor barrier. He stresses keeping the insulation flush with studs while leaving an air gap between the barrier and the concrete slab to avoid condensation and mold. Janzen then illustrates how a simple nail for hanging a picture can puncture the vapor barrier, creating pathways for air and moisture infiltration. He contrasts the traditional batt‑and‑poly approach with 2‑pound closed‑cell spray polyurethane foam, noting the foam’s built‑in vapor‑barrier rating, its resistance to nail penetration, and its higher upfront cost. The video’s purpose is to educate homeowners and renovators on proper moisture control, the hidden risks of everyday actions, and the trade‑offs between cost and performance in vapor‑barrier solutions.
Chapters
Today we just arrived on site and we are going to be talking a little bit about where does moisture belong? And that's obviously not in your walls. So let's grab a couple tools. Looks like the boys loaded up the big hammer for me, so no one's going to be safe. Got my, got my knife, my drill, and gloves. Let's talk about vapour barrier. So why is vapour barrier so important? Well, we want to stop moisture and air from flowing in and out of your home, and we don't want your wall to be unhealthy and have that moisture trapped in there. So having a proper vapour barrier is super important. All right. So in a normal batt and poly situation, this is obviously a pretty ugly piece of batt insulation that we have, but we're just kind of for demonstration purposes. We're going to be putting that in the wall. Now, there's 2 things you want to have happen when you install your batt into the wall. One, you want to have it flush with the studs as much as you can. You want to have it so there's no gaps in it. But most importantly, you want to have it so it doesn't touch your concrete behind. So as you'll notice, there's a gap in behind here so that airflow is in there. The problem with batt and poly is if it does touch the concrete, the concrete does get cold, which it could condense. creates frost, that frost attaches to the back of the insulation, that insulation has dust in it, all of a sudden you have something that may potentially cause mold or issues down the road. So having that airflow in behind there is 100% a must in this situation. So now that we have our plastic vapor barrier up, you can see that you have your insulation, your R-value in behind, and the vapor barrier here. And the vapor barrier's job is to stop moisture from traveling through this wall into the backside and vice versa. Here's the rub. Your wife comes up to you and says, hey, I want Honey, I want to hang this amazing picture that I have. Can you put it on your wall? And you say, yes, dear, because that's what your job is. You come over, you grab your hammer, your nails, you get— tap all that in there, you get it all ready to go. You grab your wife's favorite picture and you put it up on the wall. Now it seems like you're not really doing much, but what the problem is, is that you're breaking that vapour barrier. You're punching a hole in that plastic, and now moisture from inside the house can get into the wall and potentially moisture from outside can get in. So what you're not seeing obviously is that nail that we put in for the picture is going through the drywall and puncturing a hole into that vapour barrier, and that is what causes the air infiltration/exfiltration, again, that moisture to move in and out of your home. So the alternative to using a batten poly is using our 2-pound closed-cell polyurethane foam. Now there are some disadvantages with the polyurethane foam, mostly the cost, the initial cost of install, but the advantages typically outweigh that. And what we love about it on the vapour barrier side is that this whole thing is actually a rated vapour barrier, and when you drive that nail into the polyurethane foam, foam, unless you drive the nail through the whole complete system, you don't break the vapor barrier, which stops any of the moisture from going into your wall. Around here, vapor barrier matters because water doesn't belong in your walls. It belongs on your lawn.
