Housewrap for extended time?

sirmike68 · July 08, 2010, 08:19:48 AM

I plan to finish off my cabin structure this weekend up to the point where the shingles are on the roof. I do not have the time this year to put the windows in or any type of siding. My question is should I just leave the OSB exposed until next year or should I wrap the cabin in TYVEK? Or will the OSB be fine? I live in northern Alberta, Canada. Any suggestions appreciated.

THX

Kiwi55 · July 08, 2010, 08:53:52 AM

I just wraped mine using Tyvek Commercialwrap. Looks the same as normal housewrap but has a 270 day exposure time. But it is much more expensive.
...Paul

July 08, 2010, 08:55:37 AM

I built the shell of my place in the record breaking rain last summer in Maine. My sheathed walls without tyvek got rained on A LOT. I can tell you the the edges of my 7/16" OSB swelled to about 5/8". Supposedly this doesn't compromise the structural integrity but it makes me wonder. It wasn't really a problem although I had to make the bird's-mouth cut on my rafters a little deeper. I believe tyvek is rated to be left exposed for about 180 days. My tyvek has been exposed for about 11 months now, but a least my OSB has finally dried out.

rocking23nf · July 08, 2010, 09:13:00 AM

My cabin in Barrhead Alberta has had tyvek on in for a year now, and it hasnt appeared to have lost any strength.

NM_Shooter · July 08, 2010, 09:27:27 AM

This is probably more of a UV exposure thing than anything else. If so, then there will not be a hard-fast rule on exposure time.

It decays much faster her in NM.

I'd put it on anyway. It won't hurt anything by being up, and will provide some protection. It is cheaper and easier to replace Tyvek than it is to replace OSB.

July 08, 2010, 09:32:05 AM

Northern alberta is one of the sunniest places in north america, the sun stays up till 11pm and rises at like 5 in the morning. The downside being in December its dark at 4pm, and sun rises at 9am.

dug · July 08, 2010, 09:35:37 AM

I would wrap it even if you had to tear it off and replace it in the spring (due to degradation).

As Jeff pointed out, the OSB will swell quite a bit and when it does it becomes somewhat flakey, and I believe it loses some (maybe a lot) of its ability to resist nails pulling through. When it swells, the nails sink into the OSB. Don't ask how I know this.

tyvek is relatively cheap.

Jeff922 · July 08, 2010, 10:28:58 AM

Yeah, I think the issue is with UV degradation. If you leave a tent out in the sun for a while it will get destroyed. And the sun doesn't care if you paid big bucks at LL Bean or North Face. I have not noticed any degradation of my Tyvek other than the Dupont logo fading (Dupont has had my house for free billboard space for long enough anyway). But is UV degradation obvious? I mean can Tyvek performance be compromised on a level that can't be seen? Has anyone ever seen degraded Tyvek? What's it look like?

NM_Shooter · July 08, 2010, 10:58:15 AM

Now that I think about it, don't bother to tear the old off if it is still tight. Just put a second sheet over it. Or heck, if you worry about stuff like this anyway, just put up two layers initially and be done with it.

You might even just fold it in half when you are putting it on initially to get two layers but one installation labor.

The top layer will provide shade, and the bottom layer the protection. It will cost a bit more in material, but will save you having to put it up twice.

July 08, 2010, 11:17:13 AM

Holy cow I will not even suggest tar paper as much discussing that has caused here in this forum

Clearly an issue as tender in the hart as Chevy virus Ford and Democrat virus Republican. One thing I would like to ask is how much moisture will it be subject to and type? If is is all snow and blows right off that is one thing but if it twenty inches of hard driving rain that is another. If it is snow that will just sit up to the eaves and melt not being able to drain away that is another. When will you be returning to your build?

rocking23nf · July 08, 2010, 11:22:32 AM

its alberta, very little rain, mostly dry, just extremely cold winters.
I found tar paper didnt work well for me, after a weekend exposed on my roof, it all started to curl up on the seams.
I ripped it all off, and put weather and ice shield over the whole roof instead.

sirmike68 · July 08, 2010, 02:02:08 PM

The weather is just like rocking23nf stated and by the sounds of it I will put up the TYVEK as most have said its easier to replace TYVEK than OSB. MAkes sense to me.

THX

SardonicSmile · July 08, 2010, 04:37:54 PM

Really depends on how much it rains. I would be worried if my sheathing got rained on more than a couple times..

rick91351 · July 08, 2010, 05:21:19 PM

I think I would do the TYVEK if it were me. Then next year take a long hard look at it and determine if it needs to come off or it wintered well. By then we might have a agreement on tar paper or TYVEK but I doubt it...

That was sort of the weather report I was expecting. Back in the seventies my father and I almost bought a huge ranch up at Lesser Slave Lake, my mom and my wife vetoed the idea. I mean the papers were being drawn up. Oh Well.....

July 08, 2010, 05:55:34 PM

Not to hijack, and not to start a tar-paper vs. tyvek flame war, but...

My cabin will be left un-sided over a Nova Scotia winter. Sheathing is 1x6 T&G spruce. Finish siding will be cedar shingle over tar paper. Do I apply the tar paper this year and leave it exposed or wait until just before siding goes on? The same T&G spruce siding has help up very well unprotected on my shed for the past four years, but I do get water staining on the inside, which I'm hoping to avoid in the cabin.

Thanks in advance for any help.

MountainDon · July 08, 2010, 06:25:37 PM

If you want to avoid water staining on the interior then you should cover the exterior.

I used #15 felt (tar paper) on the exterior walls. Half to two-thirds of the exterior remained in tar paper mode from August through the winter until late spring before it was covered with the final cement board siding. I nailed all the paper edges every 6 to 8 inches using plastic button capped galvanized ringed roofing nails. I overlapped the upper sheet over the lower by 8 inches minimum, more in places. (I had a 9 foot wall height so required 4 horizontal runs which provided lots of extra for lapping.) Where I had one horizontal run end, mid wall, and another overlap to carry on I used 18 of overlap. Probably more than necessary.

The exposed paper saw some rain, some snow and a fair amount of wind. There were no problems.

The roof was also left exposed with #30 felt for a few months. It too was nailed securely with button caps. No problems there either.

Yes, the paper edges curl a little but the button cap nails work very well. When it gets wet it gets a rather wrinkled but that passes as it dries out.

davestreck · July 08, 2010, 06:40:22 PM

Thanks Don, just what I wanted to know.

builderboy · July 14, 2010, 06:44:09 AM

Dave, I'm in NS too. I tar papered and covered with pt lattice. It sat for 13 months (with no problems) before I got around to siding. Lattice may cost more than Don's button cap nails but if you're messing with code you'll have to space your shingles off the tarpaper/house wrap anyway.