PT vs non-PT vs exposure to elements?

[Megado]

Ok...I'm going to throw out a novice question that I'm sure many have wondered about but few have asked. Well...at least I hope I'm not the only one wondering!

I'm going to begin building a monitor style barn this spring on my property that will have .60 PT post and skirt boards (no concrete slab). This property is a weekend place so more than likely there will be extended periods of time when no work will be done on the barn. My question pertains to the rest of the SYP wood above ground (roof rafters, purlins, girts, loft joist, loft decking, etc) knowing they could be exposed to the elements for a potential length of time before the roof goes on or things get dried in (could be the end of the summer)? Are there any "guidelines" for duration of a non-PT wood structure before something bad starts to happen?

Thanks in advance for thoughts and advice...
Jim H.

 

[diyDave]

I have heard that the lifespan of PT poles placed in the ground is 15-20 years. Having animal manure or lots of moisture near the poles can significantly reduce the lifespan. There are a few new designs on the market, right now, one that uses a shrink wrapped plastic around the base of the pole, another uses concrete and steel below ground, and laminated (3-2"X6"'s) instead of regular poles. If you want to find out more, I have seen both types advertised in the Lancaster farming newspaper out of Ephrata, Pa. If you do a google search, I'm sure they have a web site.

 

[SteelDust]

Ok...I'm going to throw out a novice question that I'm sure many have wondered about but few have asked. Well...at least I hope I'm not the only one wondering!

I'm going to begin building a monitor style barn this spring on my property that will have .60 PT post and skirt boards (no concrete slab). This property is a weekend place so more than likely there will be extended periods of time when no work will be done on the barn. My question pertains to the rest of the SYP wood above ground (roof rafters, purlins, girts, loft joist, loft decking, etc) knowing they could be exposed to the elements for a potential length of time before the roof goes on or things get dried in (could be the end of the summer)? Are there any "guidelines" for duration of a non-PT wood structure before something bad starts to happen?

Thanks in advance for thoughts and advice...
Jim H.

Your OSB will be the hardest hit. That being said, my loft decking is Exposure 1 rated OSB. Which according to the APA is designed to be able to be exposed to the elements for a normal course of construction (whatever that means) without issue. I've had the OSB up since Thanksgiving, no adverse effects, and being that this is Western WA, it's been wet every day since. The other wood (girts, purlins, etc) may weather and change color but is not going to have any significant degradation in the time frame that you are discussing.

A friend of mine bought a place that had a framed in pole building on it. The previous owner stoped working on it three years prior to selling the place. All of the wood was a weathered gray, but still structurally sound.


One word of advice, put any T&G OSB up when it's dry. Any swelling at all, even from high humidity, and the slight swelling makes it very difficult to get the panels to fit together tightly.

 

[Megado]

Thanks SteelDust. I remember you stating in your thread about the trouble you had with the T&G OSB that had swollen from the rains and made a mental note of your comments. I've seen houses framed where work stopped for whatever reason for an extended period of time and had wondered if there was any consequences to the stability of that wood (warping, lost of structural integrity, etc.)? Guess I won't worry about it.

Anybody have suggestions on storage of material if I have to leave the job site for a few weeks? Unfortunately I don't have an enclosed building to store it in. Obviously I'd make every effort to only have enough material on hand for the time period I'd be there, but as we all know, we don't live in a perfect world so I'm sure there will be times when I'd have to store it somehow. I'm sure a search of the forum will find plenty of posts on the subject, but that's one additional thing I'll need to determine the best solution for.

Jim H.

 

[Ford850]

Storing wood covered with a tarp will be fine for most of it. It will get damp under the tarp but it dries out fast when you uncover it to use. If you have OSB or plywood coming, I would take and extra step to keep it dry. I would lay a large plastic sheet down, covering the pallets or skids, and set the OSB and/or Plywood on that. Then wrap the plastic up around the lumber and tack it in place with some strips of wood. Then cover that whole mess with a large tarp or plastic to keep it extra dry. Most of the moisture I had came from the ground and was trapped under the plastic. I think you will eliminate that problem with the lower layer of plastic.

 

[Nat]

I think OSB is misunderstood pretty often. If you are talking about 1/2" on a wall as long as the edge isn't exposed to the worst weather it will last a loooooooooog time. A house close to mine was started ans framed then roofed. The family had a tragady and stopped construction 20 years ago and it is still there, It's somewhat weathered and discolored but still there, If you are talking about flooring something with it and are talking about the "ADVANTEX" type it will last a very long time even exposed to the worst nature can throw at it. I made a chute for pouring pool base, A concrete/vermiculite mixture from some scraps when I built a new house in 1997 and we used it weekly, left it laying outside year round and washed it out with a hose and it lasted till the treated 2x4 side members broke 6 years latter. I wouldn't hesitate to floor a trailer with it, if fact I have one now with a floor made of 3/4" ADVANTEX and don't expect needing a floor before I need tires.
Now as to your question on framing with treated lumber over kiln dried I would think it would be better and cheaper to use kiln dried unless you are talking about taking years to finish and then it would need to be many years. My experence with treated is it warps pretty badly unless supported the whole length. An example is a wood deck that is nailed every 16" is fine but if a treated board is laid on a deck and nailed only at each end it would warp and twist in the sun badly, more so that kiln dried lumber and the cost is nearly double, so it doesn't seem too feasible to me.
This isn't supposed to be a soapbox, just trying to answer some of your concerns. HTH, later, Nat

 

[Megado]

I think OSB is misunderstood pretty often. If you are talking about 1/2" on a wall as long as the edge isn't exposed to the worst weather it will last a loooooooooog time. A house close to mine was started ans framed then roofed. The family had a tragady and stopped construction 20 years ago and it is still there, It's somewhat weathered and discolored but still there, If you are talking about flooring something with it and are talking about the "ADVANTEX" type it will last a very long time even exposed to the worst nature can throw at it. I made a chute for pouring pool base, A concrete/vermiculite mixture from some scraps when I built a new house in 1997 and we used it weekly, left it laying outside year round and washed it out with a hose and it lasted till the treated 2x4 side members broke 6 years latter. I wouldn't hesitate to floor a trailer with it, if fact I have one now with a floor made of 3/4" ADVANTEX and don't expect needing a floor before I need tires.
Now as to your question on framing with treated lumber over kiln dried I would think it would be better and cheaper to use kiln dried unless you are talking about taking years to finish and then it would need to be many years. My experence with treated is it warps pretty badly unless supported the whole length. An example is a wood deck that is nailed every 16" is fine but if a treated board is laid on a deck and nailed only at each end it would warp and twist in the sun badly, more so that kiln dried lumber and the cost is nearly double, so it doesn't seem too feasible to me.
This isn't supposed to be a soapbox, just trying to answer some of your concerns. HTH, later, Nat

Thanks Nat for the info. I threw out the question b/c I had an experience once long ago where I had a few 2x4's interior studs left over from a small project and covered them with a tarp only to find a few weeks later that moisture had gotten inside the tarp and the studs were warped badly. I've always wondered since then knowing that I'd more than likely have to store material outside again. I guess the key is keeping any material as dry as possible.

 

[tallyho8]

I notice that you are in Houston and so your humidity is almost as high as ours in SE LA. If you are installing a steel roof on runners you will have condensate running off the bottom of the roofing onto the runners quite often. The runners will rot fairly quickly if not treated. When I install steel over treated runners, I cut strips of feltpaper and staple it to the tops of the runners to protect the steel from the treated wood.

 

[jimmysisson]

There's a new product out which is OSB with a plastic/vinyl skin over one side that sheds water, called Zip sheathing. It doesn't cost much more than regular OSB, though to make the "system" work you need this expensive tape for the joints. You could use that for the roof, as they promote that it does away with the need for 30# felt paper if you don't get to shingling right away. May not be available in your area? ZIP System Wall - Huber Engineered Woods As contractors, it saves us money by eliminating labor for Tyvek and felt both. If you skip the tape, at least the surface won't swell up in the rains.
Jim