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Tyvek or Felt


tim5055
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From reading around the web I figure there will be opinions on both side of this, but....

30 year old house in the DC suburbs (NoVA) and the metal siding looks every minute of its age. I plan on having the siding replaced with HardiBoard/HardiTrim but am unsure of what to put under it. The contractor prefers 15 pound felt (or whatever you prefer to call it) but says if I want Tyvek or another product he will install what I want.

So, what says the jury?

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Feeling adventurous?

You might consider trying Blueskin VP - it's a new high-tech product that is supposed to be a vapor permeable air barrier.

Tyvek and most wraps fail because they trap moisture against a building and don't allow the structure to dry the way felt does. The Blueskin stuff supposedly allows the home to dry to the exterior like felt but has superior wind stopping characteristics like wrap.

Check it out at www.henry.com .

ONE TEAM - ONE FIGHT!!!

Mike

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From what I've read over the years, multiple layers of a WRB is better than a single layer.

I'd rather see no WRB, plywood sheathing, with a properly installed rain screen, than fiber cement jammed up against a single layer WRB (especially Tyvek)

I'd probably go with Tyvek, covered with a 30# felt over a rain screen if I were doing it--- just because I'm picky.

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From reading around the web I figure there will be opinions on both side of this, but....

30 year old house in the DC suburbs (NoVA) and the metal siding looks every minute of its age. I plan on having the siding replaced with HardiBoard/HardiTrim but am unsure of what to put under it. The contractor prefers 15 pound felt (or whatever you prefer to call it) but says if I want Tyvek or another product he will install what I want.

So, what says the jury?

If he can put it on without tearing it up, 15 pound felt works just fine under hardiplank. 30# felt is better, but it's a pain in the butt to work with. Also, consider Jumbo Tex. Be sure to use Vycor or something similar around the windows.

Tyvek is ok but, in my experience, it lets water in around every single nail & staple hole. I used it in the past, but no more.

- Jim Katen, Oregon

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From what I've read over the years, multiple layers of a WRB is better than a single layer.

I'd rather see no WRB, plywood sheathing, with a properly installed rain screen, than fiber cement jammed up against a single layer WRB (especially Tyvek)

I'd probably go with Tyvek, covered with a 30# felt over a rain screen if I were doing it--- just because I'm picky.

I have taken apart several assemblies that started with two layers of tyvek, usually in the middle of winter when something is leaking because of ice dams, and there is always a sheet of water (or ice) between the layers. For lap siding 15 lb is plenty strong, easy to work with, and with generous 3-4" laps is very reliable.

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Sorry about the delay in getting back with everyone. With a death in the family I was out of town for the past few days.

Now, answers and comments...

30lb felt, just like on the roof.

How long will it be between having the building paper put on and finish siding? (sun exposure)

Matt

Matt, Hopefully only a few days at most.

Feeling adventurous?

You might consider trying Blueskin VP - it's a new high-tech product that is supposed to be a vapor permeable air barrier.

Tyvek and most wraps fail because they trap moisture against a building and don't allow the structure to dry the way felt does. The Blueskin stuff supposedly allows the home to dry to the exterior like felt but has superior wind stopping characteristics like wrap.

Check it out at www.henry.com .

ONE TEAM - ONE FIGHT!!!

Mike

Mike, at times I'm adventurous but this is really not one of them. Through the years I've delt with "dreaded" failing lp siding problem and FPE Stab-Lok electrical panel (including a dead short in a lighting fixture that did not trip the breaker), so I'd really like something that we know works.

Why not just go 'whole hog' and give your contractor a copy of the HZ5â„¢ Best Practices - James Hardie® Products Installation Guide?

Marc

Marc,

That was one of the first things I sent him but unless I'm missing something it only says that it must be installed over a "Water-resistive barrier". While they imply that you should use HardieWrap® weather barrier, it does not seem to require it.

So, If I am reading the responses correctly, while it is not everyone's first choice, 30# felt is acceptable to everyone with 1/2 lapped 15# a second choice.

Be sure to use Vycor or something similar around the windows.

- Jim Katen, Oregon

Jim, I specifically asked that "All wall penetrations will be flashed utilizing self-adhering, self-sealing, butyl material". Is this good enough or should I specify Vycor?
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Jim, I specifically asked that "All wall penetrations will be flashed utilizing self-adhering, self-sealing, butyl material". Is this good enough or should I specify Vycor?

Nah, they're all pretty much the same. Heck, if you're careful 15# felt splines work just fine. It's about the workmanship.

And speaking of workmanship, why not do what the big boys do and ask him to install one window as a mock up? He puts it up, you approve it, all of the boys on the crew look at it and install the rest of the job the same way -- no language barrier problems either.

- Jim Katen, Oregon

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-- no language barrier problems either.

- Jim Katen, Oregon

You've been in the DC area I presume

This is construction in America.

I think English is a second language for most of the building trades regardless of geography.

Yes, and it was that way 40 years ago when I was a kid on the job sites too. But then and there, everyone spoke Italian. Oddly enough, there was one English phrase that everyone knew back then and that everyone knows now. It hasn't changed in 40 years:

Can't see it from my house!

Ain't life grand.

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