Can tyvek carefully taped be as robust of an air barrier as exterior foam insulation?
Homeowner in Long Island ny. Getting new hardie siding on the house. Our house has very few overhangs in an area that doesn’t get a lot of sun and significant rain, so my contractor recommended taped tyvek and a rain screen mat over the tyvek. He recommended this instead of tyvek plus exterior insulation. Bc of the fact I have little overhang a rain screen plus exterior insulation is not an option, as it would stick out too much
Can the tyvek taped meticulously and installed with cap nails bc as effective an air barrier as the foam board? Air sealing is super important but having a dedicated rain screen mat seems more important. Thanks!
GBA Detail Library
A collection of one thousand construction details organized by climate and house part
Replies
Foam board is typically not detailed as an air barrier, although it could be.
Tyvek is a fine product, but taping it will be fussy, and if not done meticulously, will negate much of the benefit. You could consider a self adhered product like Henry Blueskin or similar.
In either case, special attention needs to be paid around windows to ensure that whatever new product is installed is integrated into how the window was originally was originally flashed. (Hopefully it was...)
Tyvek is tested to be airtight, it lays flat, it's reasonably durable and the appropriate tapes stick well, so there's no reason it can't be used as an air control layer.
Unfortunately many, probably most builders who use Tyvek rather than the tougher European alternatives are not familiar with good airtightness techniques. If they aren't, a self-adhered membrane as Patrick recommends is a good choice. Blueskin is one; Pro Clima, Siga and Rothoblaas are European companies that have high-quality versions as well.
Thanks Patrick and Michael. Good suggestions. I really need a dedicated rain screen mat I think over my wrb. As mentioned, I have very little overhang and a lot of rain in my area. I’m just wondering if those self-adhered membranes are widely used in conjunction with a dedicated rain screen mat over them. I know the self-adhered membranes are very popular but most installs I see just have blueskin or something similar without the mat over them.
Additionally tyvek is a tried and tested product so adding tyvek brand rain screen mat over it seemed like a reasonable compromise. But your caveats about taping and air sealing tyvek are well taken
A new home I designed directly on the Maine coast has CDX sheathing, Henry Blueskin VP100 self-adhered WRB, Obdyke Slicker Classic rain screen and white cedar shingle siding is nearing completion now, and I've done several similar projects with no problems. I prefer a deeper rain screen when possible but in this case it was going to make exterior detailing too complicated.
Great thanks. And final question on this. You have no hesitation mixing and matching brands? Blueskin wrap and obdyke rain screen?
If you want to stay within a system, Henry also has a mesh rain screen product similar to Slicker Max. I saw it recently at a Kuiken Brothers show and the Henry rep mentioned it's popular under cedar shingles, so there's no reason it wouldn't work under lap siding as well.
(That said, I would have no problems mixing products like Michael has done with Blueskin + Slicker.)
Good info, Patrick. I appreciate it.
Mike,
If you want to use a sheet WRB as your air-barrier, I'd go with Tyvek Commercial, rather than regular Tyvek, which tears easily, especially around fasteners.
Additionally if either of you could commenting on taping the plywood seams, I would appreciate it. And with what product. Thanks!
Taping plywood seams is a PIA. It's possible but requires a few extra steps. This is one area where using a self-adhered membrane makes sense. I would stick with that, or with carefully taping the Tyvek.
Great thanks!
I've had no issues taping new plywood with 8067. I can see with older very dusty it sheathing there would be issues with sticking. You can always prime the seams with spray adhesive.
As for air tight house wrap installs, don't forget about sealing the edges not just the seams. You can use acoustic caulk behind the house wrap for example at the top and bottom.
A big air leak in most houses is the foundation joint, this is the one intersection you want to pay extra attention to. You can tape the bottom of the sheathing to the foundation with Siga Fentrim or seal it with liquid flash. You can then drop the bottom of your siding a bit and cover it.
Thanks Akos for the helpful tips