Weather Damage

[rdpecken]

In following another topic (First Day Cottages) I saw that there was some discussion of the affects of weather before a structure is dried in...

...the six months or so could be near it.  It can vary greatly but after six months of off and on rain, OSB t+g flooring was getting to look pretty rough- kinda rough on top with swelled wood chips... :-/

I'm just about ready to start my floor in northern Arizona.  I know we are not like the Pacific Northwest, but we do get thunderstorms every other day or so from July to mid-September, and we are building in stages as money permits.  It could be next spring before we get dried in .

So, how can I protect the floor for a period beyond a few months? Would a coat of Thompson's Wood Sealer for decks be effective?  Should I build a removable mini-roof to set on top of it?

When we built our 8x10 shed under similar circumstances, I put a tarp directly on top of the subflooring (T&G plywood).  The plywood blistered from condensation.  Not a lot, but it was only exposed for a month :-/.

Any suggestions would be appreciated.
Randy in Arizona

[jdew]

Your better off to leave it totally exposed than to cover it with a tarp or plastic sheeting etc.  Of course you found that out when you built your shed.  

If you're building with plywood than it should be rated Exposure 1 - which means it is made with waterproof glue and can be exposed for a period of up to 6 weeks (I think that's right but I could wrong on the time - its at least 6 weeks), without any problems.  Of course you'll get streaking from the nails and some staining.  Best thing to do is to try to get the roof on as quick as possible.  I suppose a sealer of somesort wouldn't hurt.

[JRR]

I've tried fortified linseed oil (Olympic ??) and even (Helmsman ??) spar varnish on plywood sub-flooring and framing that was to be exposed for a while.   The coatings surely helped ... but the results  were "under-wheming".   I really flood-coated the plywood ... and though it did not blister,  it quickly blackened... and the plywood sheets weren't fastened to the joists, they were just loosely scattered about for temporary flooring.

I'll share with you what I intend to do on my next DIY building project:

1.  Fully oil prime all framing wood as soon as it arrives on the job site.   Tarps can be used as protection over stored wood, but an air space under the tarp is a MUST.   These actions will help prevent sun and water damage.

2. Do not install subflooring until the building has a roof and walls.  For a temporary work surface, (in required sections) install decking boards atop the joists.  Use decking screws for easy removal later.  A full complement of screws isn't necessary since the decking is to be temporary ... but it must be safe.  To save time and materials, use an adnormal spacing gap (1"+ ??), between deck boards ... resulting in a "safe-enough" working surface, but something that air and rain water can pass easily through.  Hopefully the deck boards will live again someday in a real deck.   .... alternatively, a "properly" installed decking might suffice as sub-flooring (I haven't done the math on this plan).

Both of these actions require a bit more up-front investment ... but can eliminate some of the weather-worries.

[spinnm]

Northern AZ?  On top of the rim?  Flag?  Snow?

If it might be next spring, I'd skip the flooring too.
Thompsons is really not a very effective product.
Exterior grade plywood tres expensive.

Possible to build something that would shed the water?  A "tent" of some sort?.  If you wind up with tarps, need to rig up something that will flex.  Otherwise tarps will just rip to shreds.  We've been somewhat sucessful anchoring tarps with bungees through the grommets.  Should last a season.  Just thinking out loud.  Maybe sleep will inspire me.

A sacrifice layer of something?

[rdpecken]

Thanks for all of your suggestions.  It sounds like the water sealant probably wouldn't help a lot. We are building at 5700 feet, about 70 miles west of Flagstaff in the Juniper Mountain Range. We get some snow, but it usually melts within a few days.

I like the idea of a "sacrifice cover".  How about laying roofing felt and rolled roofing over the floor?  Then we could remove it after drying in.  Would it likely have condensation problems, too? I could put a vapor barrier under the floor.

[Amanda_931]

JRR's right.

Roofing felt is only sort of waterproof, and it's not very sturdy, it can be torn by the wind.  In other words water will get in and then be held on the surface to make a mess.

There is second way.

[glb]Put the roof up first.[/glb]

Get the roof up on poles well (18"-2 feet) outside of the foundation, build up to it.  It will have to be built as a free-standing roof, a lot pf preparation and what will be serious overbuilding after the house is completed.

(Ianto Evans even mentions lowering the roof onto the finished building--sounds like a don't try this at home solution to me, even if I had a couple of dozen strong friends to help.)

and a third way.

Somebody in one of the magazines recommends a finish floor of roll roofing put on with the glue (nasty sticky black stuff) and then covered with a handful of coats of latex paint.  Have to do some right serious sealing of the sides.  And you don't ever take it off.  Repaint it  another color, sure.

[glenn-k]

Thinking about this a little more, I think a long 2x8 or something suspended a reasonable height over the work area and a large well tied tarp for the work season would do the job, or even covering it when not working, blocking up and leaving room for air circulation- you don't need to keep weather off  all the time and an occasional slip up wouldn't hurt a lot.  In case of the occasional water puddle, a high power leaf blower will clear it pretty fast.  A decent cheap tarp will last about 6 months.  Costco has some heavy ones.

[JRR]

I have used the tarp thrown over a balloon framing ... no wall sheathing, but plywood was on the roof...and yes, I got a few months out of it.  The particular tarp was not a new one and was not very heavy material ... but it was huge ... maybe 50' x 30'.   You can't imagine what even the smallest breeze will do to such a sail!   We installed it on what we thought was going to be a rather quiet fall afternoon .... we became quite a show for the neighborhood, as the tarp would go flying away several times just before being secured.  Four of us finally got it in place and secured on the bottom edges ... and then threw several small diameter ropes up-and-over to help hold the tarp down.

If I had done a better job of softening up the corners of the framing (wrapping sharp edges with old rags, etc) the tarp might have lived even longer.  But an early spring wind finally split it in halves.

[rdpecken]

...You can't imagine what even the smallest breeze will do to such a sail!...

Actually, I do have an idea what the wind can do to a sail... I was getting some supplies out of my truck one day, when I heard a commotion across the meadow... Looking up, I saw a huge dust devil working it's way down the mountain and across the meadow.  It took about 30 seconds to reach my work area, and at the last second, veered right into our shade structure. What luck.

It pulled the inadequate anchors (6 inch tent stakes) right out of the ground, and flipped the whole thing up in the air  about ten feet, and deposited it about 30 feet away from where it started.  Now I have much longer stakes, 2 ft rebar, to hold it down.


So, at this point, I'm thinking I need to gather up enough money and time to complete the drying in within a couple of weeks, rather than 6 months or more.  Thanks again for all of your insights.

[glenn kangiser]

I had one of those too rd.  Mine looked just like yours although it was shaded by a hill excavation and had large rocks and railroad ties tied to it.  The time it looked like yours was after the rr ties were untied after a period of extended calm.

Granted, it doesn't work great - is pretty noisy and will probably do a great bit of flying around and tearing up.  Your plan sounds best.

Parasailing anyone