What is the proper procedure for installing Tyvek in basement?

2/20/2015 at 1:29:17 PM

Hello,

The reason Tyvek or other brands like (TypeR) is not reccomended is because once you seal the concrete wall with this barrier and then seal off the batt insulaiton with the 6mm plastic poly barrier you will create condensation. This will cause mold on the inside of the Tyvek and the 6mm Poly which can spread to the batt insulation.

So the correct procedure is cement wall>wooden or metal studas with batt insulaiton> 6mm poly barrier>drywall.

The tuck tape on the seams should be connected to the 6mm poly barrier which you would have 12 inches sticking out on the top and bottom of the wall across the whole length of the wall and then you would bend the top or bottom 12 inch of the poly and tuck tape it with the other poly to seal the envelope.

2/20/2015 at 5:45:00 PM

Roxul recommends adding Tyvek or another air/moisture barrier so that the insulation is not in direct contact with the concrete. Since its a moisture barrier not a vapor barrier it should not cause the problem you described.

2/20/2015 at 10:58:38 PM

Abfab,

They way you are describing is correct. In Oakville this is the only thing the building dept will accept. Under no circumstances is insulation to touch concrete. They also will accept 15lb felt paper.

2/21/2015 at 11:00:23 AM

Mark,

How is the Tyvek installed? Do I use tuck tape, or an acoustic sealant against the concrete? Since I'm installing Roxul Comfortboard against it I can't staple it to the studs as some people do when only using batt insulation.

2/22/2015 at 12:15:05 PM

Hi Abfab,

I'll let you know how I build all basement finishes. Now its a little more costly. But the results are superior. And your basement will be warm and dry.

1) We take 2" Foam core and glue it to the concrete walls. The insulation between your floor joists that is covered with the vapour barrier is removed and we add R-24.

Then we use Tuck tape and seal every joint on the Foam core. then install knew plastic vapour barrier over the insulation against the outside between the floor joists. Completely and carefully tape it up to the Foam core and staple it to the adjoining lumber and floor above.

We then frame the whole basement, wire and plumb etc.

Then we add Roxul R-20 in the framing. The frame sits out with space from the Foam core so we have room for any R-value the client wishes to install.

The Foam core and plastic is your vapour barrier. So you add nothing else but your drywall. And you end up with R-30 insulation in your basement. The two inch Foam core has an R-10 value.

Enjoy

2/22/2015 at 4:52:24 PM

You can use either accoustical sealant or tuck tape, either will do. You can also pre-build your walls with the Tyvek stapled to the back. The main idea is to prevent moisture buildup on exterior walls from reaching the insulation. Just make sure your tyvek is facing the right way so the repellant side is out and the breathable side in or you're gonna have trouble.

You don't need vapor barrier if using rigid foam insulation, just seal all the joints. However, using it never hurt anyone and having a secondary barrier in place isn't a bad idea. Just make sure the insulation goes on the warm side of ALL insulation to prevent moisture buildup.

Best to check with local building codes to ensure compliance or you may end up pulling it all out and redoing it.

2/22/2015 at 5:55:00 PM

So just to clarify, am I looking mainly to prevent the insulation from touching the concrete or to create a seal between the concrete and interior? I know with vapor barrier its important to seal up all the edges, around electrical boxes, etc. Does the same apply to tyvek?

2/22/2015 at 11:31:18 PM

The Tyvek is generally stapled to the top plate that the first floor joist sit on and just drapes down to the floor, the stud walls are then put in place and generally a 1inch space is between the stud and the tyvek allowing air to move next is the insulation, over the years studs move and insulation sags now when this happens it isn't resting against the wall but the tyvek, install 6 mil poly make sure to use butyl at bottom and tape all seams and outlets, now install your drywall.

8/12/2021 at 7:30:28 PM

Picked up on this old thread as I am finishing a rec room, did some electrical, and found some of the black paper used on the foundation mouldy and containing some moisture. This is a 2000 built home with platon on the outside, yet still high moisture content in the concrete foundation wall, side of the house. So not sure what is going on there given when I bought in 2017, I fixed all the grading to significantly slope away from the house. Anyway, although I could rip out 55 ft of exterior stud wall, install rigid foam etc etc, not willing to go to that length. I would also probably not install vapour barrier between insulation and drywall based on current thinking, but building code requires it. So, long story short, have seen different reference to using Tyvek which I am doing where I ripped out the black paper, and to be sure about direction, called Dupont. Tyvek Housewrap is not unidirectional in its function, so does not matter which way the writing faces. This is not true for some of their other products but for House wrap and commercial wrap...doesn't matter. I think i also saw this in a FAQ section of their website.

10/15/2022 at 6:47:33 PM

I am also doing a reno of my basement and its a 2002 build. I noticed the walls already had some house wrap on it, some areas was wrapped. I think the way we are going is;

Concrete Wall > Tyvek/Housewrap > Studs > Insulation (Batt) > Plastic Wrap/Barrier > Drywall.

We live in Ottawa where it gets frigid cold in the winters and it seems this is a common way people insulate their basements here. It should also be good for Toronto.

We already have studs up so I don't think we could add the rigid foam now properly behind it.