Do You Need a Vapour Barrier? Vancouver New Home Inspection – Part 1

Hi it’s home inspector David Fairbairn with Fairbairn Home Inspections and we’re here with Larry Clay of Clay Construction and we’re doing a site tour to see one of his new custom built homes and he’s going to explain to us how his wall systems are different from your standard wall system and the benefits to the way he’s doing it. He’s got some really cool science to share with us, so if you could explain how that works Larry? Be a pleasure.

Hi, I’m Larry Clay from Clay Construction and I’d like to talk to you about how do you achieve a healthy home. This can be done but it involves some cutting edge building science. What you’ll see here is some rigid insulation on the outside of the house, what we’re doing is we’re moving some of the insulation to the outside to warm up the framing on the inside. The other thing you’re going to notice is that we’ve taped all the seams, this house does not have building paper on it, this is the air barrier. We’re not using poly or plastic on the inside as our vapour barrier. We’re going to use this as the air barrier, we’re going to paint on the drywall, our vapour barrier and this allows us to remove the poly from the inside, allowing the wall assembly to breathe and not allow moisture to accumulate in the wall assembly. Come on inside and I’ll show you.

Ok, now that we’re inside of the house, what you’re going to see is you can see that we have our rigid insulation here between our sheathing. What’s going to happen is we’re going to put our insulation inside, the poly we’re not going to put inside, this only serves as a protection for our windows, but in the wall assembly, because we have rigid on the outside, this surface now will be warmer. Again, remember the Coke can from the fridge, one from the pantry, you put them on counter, which one is going to have condensation, the puddle underneath is the Coke can from the fridge. So building science, what you want to do is make sure you have warm surfaces, not cold surfaces which will give you a propensity for mould and mildew inside because of the wetness. With the rigid insulation on the outside, we now have eliminated thermal bridging making your drywall even warmer. Now you can lean again the wall for hours reading a book and you’ll never get cold. So if you want a healthy home, another great step is to have a healthy wall assembly. Larry from Clay Construction.

About the Author DavidFairbairn

Author David Fairbairn is a certified, licensed home inspector serving Vancouver and the Lower Mainland. He has been featured in the media and has contributed to "24" Newspaper, and Global TV. He has spent years working with residential and commercial building projects, and holds a Power Engineering License in BC. Why not give him a call for your next Home Inspection? Call 604 395-2795 or email today!

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