Covering a frame

FrankLad · December 04, 2006, 11:58:57 AM

The timber framers are almost finished cutting our frame and will possibly be ready to fit and raise it within the next couple of weeks.

The issue we're running into is we decided to go ahead and order our pre-cut panels but now the panel company is backed up on orders, meaning we'll have to wait until around middle of January or later before wrapping our frame.

So the question is... what are some good ideas for keeping our frame out of the weather until then?

We already have our roof decking (3/4" T&G eastern white pine) on site, as we purchased it when we got the timbers (it's all stacked and covered, of course). The panel consultant recommended going ahead and putting that on, along with a moisture barrier on top, and then maybe wrapping the posts with a temporary moisture barrier. Tar paper is the most available, and very affordable - but I'm not sure how long it would hold up.

Our timber framer suggested maybe we should consider putting "EPDM" (which from what I gather is a rubber membrane) on top of the T&G ceiling since it can withstand the elements longer and would form a permanent layer that we could just put the SIPS on. As it is more for commercial buildings, I'm not sure what type of issues it may cause in a residential setting (as far as fumes, etc.).

What do you guys recommend putting on top of the T&G?

Also...we have ordered some Land Ark to oil the frame with. Should this be done once the house is dried in, or as soon as we put the T&G on top?

Thanks for any help!

beenthere · December 04, 2006, 12:35:13 PM

I think wrapping the frame timbers with 'Visqueen' or plastic would be the cheapest. If warmth and humidity might cause mold in the timbers (at our temps in WI that wouldn't be an issue

), then I'd give them a light spray of mildewcide (bleach/water solution) to keep them from staining dark.

On our addition, which was all windows and the window-order was quite late, we wrapped the side walls in Tyvek, which snapped in the wind and drove us nuts having to listen to that sound for 7 weeks. But it kept the rain out, which was a big help.

What support is under the 3/4" T&G white pine decking? That thickness I'd call sheathing, and would expect it on no more that 16" o/c rafters. Will the 3/4" wp be covered with the pre-cut panels? Just wondering out loud here.

Raphael · December 04, 2006, 01:14:58 PM

QuoteWhat do you guys recommend putting on top of the T&G?

I have a cold roof so 30# felt (tar paper) was my weapon of choice as it breathes.
Assuming your roof panels are nail based then something impermeable is fine. If they have OSB on the underside you could create a problem if water ever got in there or the OSB was damp on install.

My experiance with EDPM is limited to what I use for interior water features and fish ponds and ponds where the liner will be exposed, it's about as inert as a polymer rubber like substance can be. There's a world of difference, on a hot summer day, popping open the cargo doors on a load of EDPM vs. a load of butyl rubber. I don't honestly know how thoroughly it's been tested for use inside air tight residential structures but it would do the job.

FrankLad · December 04, 2006, 01:46:11 PM

We do have an issue down here with humidity/moisture. However, given the time of year this is taking place, it may not be as much of an issue.

I like the idea of going with Visqueen on a short-term, temporary basis, given it is cheap and we actually have some rolls of it on hand to get started.

To give you guys a better idea, here are a couple of pictures from the plans:

Elevation/Cross-Section:

Rafter Spacing:

I think given the rafter spacing (4'-3/8"), and 3/4" boards...I wouldn't try to walk it while installing.

beenthere · December 04, 2006, 04:37:44 PM

FrankLad
I don't want to be a wet blanket, but I foresee a problem laying down 3/4" white pine T&G boards on that long a span, and then covering one side and leaving the other side exposed. Even if these boards were exposed to the same environment on both surfaces, I'd expect enough changes to occur to cause enough warping that will leave you disappointed at the looks of your exposed ceiling. I am assuming this white pine is to be exposed as a finished paneling-look between the rafters.

I will admit that I could be all wrong, and I'd hope that the boards will behave nicely, and lay as flat as when layed in place. Just maybe, if it does warp, that it can be screwed or nailed down to the added panels later in construction. That's a bit iffy too, but it just may work. :

Take my comments for what they are worth, but I don't want to see you go ahead with something with as much potential for dissapointment as this appears to have (to me). This practice of laying pre-made panels on top of 3/4 T&G on 4' centers may be more successful than my imagination or experience and I wish it all to work out well for you. Seems the boards should be fastened to the panels at the same time they are installed. Sorry for the negative reaction. Maybe others can be a bit more supportive of the 'plan' to get covered up.

Don P · December 04, 2006, 05:50:19 PM

Actually that is very common. The frame we've been working, forever :

, on has about that spacing on the roof and I have walked a roof while installing on a similar spacing, careful to walk over purlins. I've walked metal over purlins without damage come to think about it, this is not so different. The entry porch on ours has 7' spacing between outside wall and entry bent. I can push the t&g up a bit in midspan but the sag is unnoticeable. 3/4 plywood often carries a 48" roof stamp and almost half its grain goes the weak way.

I'd t&g it, tarpaper with plenty of buttonkaps and let the walls ride, counting on a final sand and oiling when dried in. But that's just me. Roll roofing or ice and water would also work if you want to spend money early ;).

logman · December 04, 2006, 07:49:57 PM

I used 3/4" yellow pine t&g on my frame and it was exposed to the
weather for a while. I have about the same span except purlins with the t&g running
opposite the ridge. I used sips also and everything is nice and flat. Someone did
suggest that I should put house wrap over it but I never did. I also had no problem
putting my weight on the t&g between spans.

FrankLad · December 05, 2006, 08:25:43 AM

beenthere: I have some of the concerns you mention. I spoke with the fella that did our plans and he said that we could back-nail brads through the T&G into the SIPs once installed. But I am a bit worried at how much the T&G may warp while it's up there by itself, before the panels go on.

DonP: Our lead timber framer did mention ice and water shield.

The question we were debating on yesterday was this... in our southern-Mississippi climate, where should the moisture barrier be permanently installed?

He said up in his neck of the woods (Wisconsin), they'd put it right above the T&G and then have SIPs and final roof, but down here it seems like we'd have it right under the roof, with SIPs and T&G beneath.

Any ideas on that? (This is just when it comes time to do the final thing - not temporary cover.)

logman: Did your frame see a lot of rain? Any greying/weathering at all?

Raphael · December 05, 2006, 09:20:41 AM

In our frame the SIPs and SKINs are our vapor barrier.
The only place I need anything else is the attic floor where we'll be using double bubble radiant barrier below the joists.

Stephen1 · December 05, 2006, 03:34:38 PM

I will not place any vapour barrier between the T&G pine and the SIP panel roof. I wa told by the SIP manufacturer it is not needed. But I did leave a nice air gap between the sips and the steel decking.

Thomas-in-Kentucky · December 05, 2006, 06:31:28 PM

Frank,

The biggest mistake I made on my house (so far) was putting down the tongue and groove before the SIPs were on site. Don't do it. Don't do it. Don't do it! I carefully followed the t&g with a plastic vapour barrier, and secured the vapour barrier to the t&g with battens. A small amount of water was able to get through the batten nails and seep beneath the vapor barrier. The vapour barrier kept the moisture from drying out (egads), and eventually where I had used clear plastic, I could see mildew here and there, even some mold, and the t&g boards warped like you would not believe. The panel supplier (for my walls, which had to precede the roof) kept pushing back the date, and eventually the clear plastic disentegrated into a million pieces and blew off the roof into my yard, at which point I just prayed for no rain. I put a vapour barrier on again right before we put the insulation and roof on.

Most of the t&g is OK, some I will have to refinish in place, some we kerfed on the backside and pulled the warp out of the boards, and one small room (200 square feet) I'll have to pull all of the t&g off and completely re-do. I'd like to say "it's just money," but the reality is I logged and sawed the timber that eventually became that t&g that evetually became junk, so its not "just money"... its a darned shame. Ironically, I used 90lb roll roofing on the part of the t&g that I have to replace, and thought it would be foolproof, but the button cap nails let just enough water in to warp boards, and I said the heck with it and ripped off the temporary roof that was causing the problem.

I do believe that grace ice and water shield would have worked in my situation, but smell that stuff on a hot summer day, and then decide if you want that smell on the inside of your house.

Hope you can learn from my mistake. My first mistake was taking the advice to "go ahead and put on the t&g and rely on the vapour barrier for a temporary roof". In fact, you really might want to delay the frame raising until the panels are on site. You see, I am bleaching and refinishing all of my timbers right now because they took on so much weather.

I used 7/8" t&g oak boards over purlins on 4' centers, and where they didn't get wet, the boards have done just fine. In fact, we walked all over the ceiling while putting it down, and althoguh it was "bouncy", we never felt like we were in any danger of falling through. Your mileage may vary with pine. If you have any worries, as you say, you could always go back and face nail with finish nails from below. But if the boards get wet before the SIPs go on, you can be sure they will warp.

Also, like Stephen and Raphael mentioned, if you are using SIPs and taking care to seal them properly at the intersections, then you already have a vapour barrier. (I didn't use SIPs on my roof - I used 2x10's with PolyIso between them - SIPs would have beena lot quicker).

-Thomas

ps. I could send you pictures of warped t&g with ruined finish - and it would make you cry, but I really don't want to take any pictures of it. I just want to fix it and go on. Like I said, "biggest mistake I've made so far."

logman · December 05, 2006, 07:35:32 PM

Yes, my frame was very grey. My wife and I spent weeks sanding
everything. My t&g got wet quite a few times and never really had a problem.
I worked at a snails pace since I was working a full time job also. I
tried to cover the t&g with sips as soon as possible but always had some
exposed. The next house I build for us will definitely be different.
I hated sanding timbers more than anything. I will get things closed in
a lot faster.

FrankLad · December 06, 2006, 02:39:57 PM

logman: Thanks for the info! Me and my brother are sanding the individual pieces (which have been planed by the framers) on horses, and I'm kinda thinking now that the sanding may be wasted effort if we can't figure out a way to protect the frame and it has to be sanded again anyway. Hrm...

thomas: I appreciate hearing your experiences with this. I'm sending you an email with some specific questions.

FrankLad · December 07, 2006, 01:37:23 PM

Spoke with a couple of the timber framers over lunch break and they are thinking the best route for me to take is to oil the frame immediately after it's raised and let it sit - don't even try to cover it with tarp. They will place spacer strips above the rafters so that once the SIPs arrive, they are installed and then the T&G is installed from underneath.

I'll let you guys know how it turns out.

nutwoodfarmers · January 17, 2022, 07:22:14 PM

Same question and curious to know how it turned out for you?

We are about to tarp our frame with 10 mil visqueen for about $600 as soon as we get the roof up. We won't be able to put in exterior walls (straw bale) until July - at least 6 months from now.

Thanks for any thoughts-