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House Wrap Question

Terence McCann

By Terence McCann
in Exteriors Forum

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hausdok Advanced Member

hausdok

Posted
Posted

Hi Terry,

Technically, OSB is a vapor barrier because it has a perm rate of somewhere around .55 (I believe). So, depending on the type of siding, you might not have required a moisture barrier, although it's good building practice regardless of whether it's required or not.

Wrap isn't necessarily the best choice anyway. It's designed to stop wind, not water, and once water gets behind it th4 water is trapped, can't get out, and starts to rot the walls, unlike felt, which will allow the wall to slowly dry through diffusion to the interior over a day or more.

What type of siding was being used?

ONE TEAM - ONE FIGHT!!!

Mike

kurt Advanced Member

kurt

Posted
Posted

I'll second the "no house wrap" notion. I think it's one of those things we'll recognize in 20 years as bad practice.

Doesn't breath; I don't care what the mfg. says.

Felt. They had the conundrum figured out 100 years ago. Felt is darn near perfect house wrap.

Jim Katen Advanced Member

Jim Katen

Posted
Posted
Originally posted by Terence McCann

It was vinyl Mike.

Thanks for the replies, wasn't sure if it was a code thing or not.

The IRC doesn't require felt or tyvek under vinyl. See section 703.2. They're also not required under wood siding.

Stupid but true.

- Jim Katen, Oregon

carle3 Member

carle3

Posted
Posted

This is a problem near and dear to my heart. I have had two call backs because of the lack of any kind moisture barrier on a vinyl home. My belief is that vinyl is not a weather proof covering. IT IS GOING TO LEAK. My normal finding is at the J-channel around windows and doors. Over time this rots the OSB at the bottom corners. Caulk does not bond well to vinyl and will fail. Builder fail to detail windows and doors with protecto wrap per manufactures specifications and as I understand most vinyl manufactures require a house wrap on OSB per their specifications. Clue here, it doesn't need to be code if it is not installed per specifications it is wrong. The standards are that we are performing a visaul inspection and looking for house wrap and flashing details around window go beyond the comfort zone of what most will do but I feel these Houses with vinyl siding are ticking time bombs.

kurt Advanced Member

kurt

Posted
Posted

Vinyl siding. Ahem....

How many folks out there know that there's supposed to be flashing over the windows & doors? Yep, flashing.

The Vinyl Siding Institute recommends that all vinyl siding installations include flashings such as aluminum coil stock or similar metal drip cap material.

How many folks note the lack of flashing in vinyl siding jobs? The heck w/housewrap; how about flashing?

hausdok Advanced Member

hausdok

Posted
Posted

Hi Kurt,

I do. All the time. The complex I live in is a good example. When I moved in here in 1996 I told everyone that the windows were done wrong and there should be head flashings over the windows. Nobody believed me. 5 years ago they had to strip the siding off around every single weather exposed window and door, make repairs and then reclad them...this time using head flashings.

I think word is finally getting around to builders that leaving head flashings out - as they've been doing for so many years - is just stupid. More and more, I'm seeing new homes where head flashings have been used where just a few years ago the same builders weren't using them.

Last weekend, I took my students for a walk around a neighborhood near the college. Every student had to find one thing visually from the street on every home we looked at. At one construction site, the builder invited everyone in to look around. I was amazed to see, not only head flashings, but also jamsills.

It's a mission. Keep at it long enough and word eventually gets around within the construction profession. I just wish it would work that well within this profession.

ONE TEAM - ONE FIGHT!!!

Mike

carle3 Member

carle3

Posted
Posted

We had a problem with Semco windows a few years back. Had clients calling about leaks and after extensive investigations ruling out cauking, flashing and masonry problems it boiled down to the window frames were leaking. Semco had changed the manufacturing technique on the conrners of their windows. They use to have a insert in the mitered corner. They took this out and went to foaming the corners. This seemed to up up when the window would get torqued around from house movement and then leak at every rain into the wall. After that expereince we started to use a bib an every sill window and door.

Eric B Member

Eric B

Posted
Posted

Very often I find just the J-channel over the doors and windows (windows w/o nailing flange). In BillieBob circles the J is considered the flashing, that and a nice bead of caulk! I write up the missing flashing but I think that I'm in a minority on this in our area. I haven't yet made a big issue of the caulk, but I may change my mind on that.

We sided our house in cedar about 20 years ago. Now I wish we used felt paper with furring strips. Ever see what cedar does to building paper? Live and learn!

hausdok Advanced Member

hausdok

Posted
Posted

I dunno,

I pulled some 85 year old cedar off the entire side of a building about 6 years ago and the only thing behind it was rosin paper. The paper was in great shape and still protecting the one-by sheathing behind it. Of course, that siding had been back-primed, as it should have been, before installation, so the primer might have limited the effect any extractives from the cedar might have had on the paper.

OT - OF!!!

M.

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