House wrap AND fan fold?

[No faux zone]

I have a customer that wants new siding put up. He's asked me to price it with Tyvek and half inch fan fold insulation (it's a vinyl job). I don't normally do both. Before I consider this, should this be done? It just dosn't sound right to me. If it can be done, what goes on the wall first?

[Top Notch]

Re: House wrap AND fan fold?

Can it be done? Of course it may, its suggested. Many builders only tyvek cause the new wall cavity meets the minimum of the energy code. A more efficent job has both. Old houses are built less efficient and need the extra help. I have never seen 1/2" fanfold only board foam. As far as what goes first. I always staple tyvek to the walls and then hand nail the foam. I did have one anal customer read up and swear the tyvek be installed over the foam.

[No faux zone]

Re: House wrap AND fan fold?

Well the 1/2" fan fold is actually only 3/8". I have always been under the impression that I shouldn't have the two layers one over the other because it could trap moisture between the two. First time I've ever had somone specify it so I wanted to be sure I'm not doing something I shouldn't.

I've only seen house wrap done with board foam myself. If I had to use fan foil, we usually tape the seams and corners with foil tape to help keep out any moisture.

Thanks

[frenchie]

Re: House wrap AND fan fold?

Tyvek's pretty vapor-permeable, so is foam when there's only 3/8 of it.

[No faux zone]

Re: House wrap AND fan fold?

Tyvek's pretty vapor-permeable, so is foam when there's only 3/8 of it.

So, no reason to do them both and no danger in doing them both?

[frenchie]

Re: House wrap AND fan fold?

Pretty much, yeah.

If you do a search, it's been discussed a lot, last fall I think. Dancing Dan was doing a house with a lot of foam on the outside, was wondering whether to add a separate wrb...

gimme a sec, I'll find it.


edit: here's the thread i was thinking about -

http://forums.jlconline.com/forums/s...ad.php?t=40181

[Mike from NH]

Re: House wrap AND fan fold?

Jason,

Last fall (2007) we re-vinyl-ed an older home. Stripped the crappy 80's vinyl and the leveling / foam board, down to the origional wood siding. The city said that house wrap was code even if we were using 3/8" fan-fold. So we used that green-guard...ammo-wrap? and 3/8" fan fold. I gotta say the house holds heat!