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-   -   Best wood to avoid warping, for patio cover. (http://www.diychatroom.com/f19/best-wood-avoid-warping-patio-cover-184586/)

garya505 07-31-2013 11:37 PM

Best wood to avoid warping, for patio cover.
 
I'm going to be building a patio cover. This will be attached to the house on one side, but the other side will have a beam, probably 6"x8"x14'. Rafters will be 4"x6"x11'. Posts will be 8" round. I'm wondering what the best wood to use is, that would result in the least amount of potential warping. It will probably be Ponderosa Pine or Douglas Fir. Green or dry? I might be able to get KD Doug-Fir locally but I haven't checked. I'd rather not use a glulam or LVL. Suggestions?

Nailbags 08-01-2013 12:54 AM

Well first off don't ever use green! It will shrink and warp! Second never ever use hem fir. That is a crap shoot you either get hemlock or Doug fir. Mostly hemlock and that junk will warp twist cup etc. always use KD kiln dried less then 15 % moisture. Ponderosa pine not as strong as Doug fir I don't know how tight grain it has or how bad the knots will be. Best of luck to you. Hope that helps.

garya505 08-01-2013 11:33 AM

Thanks nailbags. There's a covered porch in my neighborhood that probably was built with green Ponderosa Pine. Looks like a 4x12 beam sitting on 4x8 corbels. The beam has twisted to the point where it looks like the thing could fall down.

garya505 08-02-2013 03:06 PM

How about Tru-dry timbers?
http://www.tru-dry.com/home.html

kwikfishron 08-02-2013 04:32 PM

Quote:

Originally Posted by garya505 (Post 1224221)
How about Tru-dry timbers?
http://www.tru-dry.com/home.html

Have you considered Redwood or Western Red Cedar? If you want the good stuff just go to a well established local lumber yards contractors desk and ask.

Any metro area I ever lived in has always had at least one specialty lumber supplier. The ones I've dealt with won't sell to the public directly but your lumber yard can buy through them for you.

Don't waste your time with the box stores.

I grew up near the Tru-Dry Kilns and unless things have changed the smallest order you could purchase from them would be a semi truck load.

garya505 08-02-2013 05:49 PM

I talked to a guy at Capitol Lumber today and he said they can order me whatever I want but it's about 4 weeks delivery time. He also said the cost is about 3X that of regular green DF. I don't mind the extra cost if it's avoids most of the warpage. Maybe I could use tru-dry for the single 6x8 main beam and 2 6x6 posts where warping would be most visible, and just use some regular DF 4x6s for the rafters.

kwikfishron 08-02-2013 06:35 PM

Quote:

Originally Posted by garya505 (Post 1224271)
I talked to a guy at Capitol Lumber today and he said they can order me whatever I want but it's about 4 weeks delivery time. He also said the cost is about 3X that of regular green DF. I don't mind the extra cost if it's avoids most of the warpage. Maybe I could use tru-dry for the single 6x8 main beam and 2 6x6 posts where warping would be most visible, and just use some regular DF 4x6s for the rafters.

You live in a kiln. You could buy the green, store it out of the sun for a couple months with good air circulation and there ya go.

user1007 08-02-2013 06:44 PM

Quote:

Originally Posted by garya505 (Post 1223607)
I'm going to be building a patio cover. This will be attached to the house on one side, but the other side will have a beam, probably 6"x8"x14'. Rafters will be 4"x6"x11'. Posts will be 8" round. I'm wondering what the best wood to use is, that would result in the least amount of potential warping. It will probably be Ponderosa Pine or Douglas Fir. Green or dry? I might be able to get KD Doug-Fir locally but I haven't checked. I'd rather not use a glulam or LVL. Suggestions?

I always used dry lumber when budget allowed.

I will say up front I miss the smell of building things out of kiln dried, a grade redwood heartwood. However, I am curious your adversion to a nice, exterior glue lam beam though? Perhaps you have only seen tacky ones? They come in all wood types you know.

I am guessing your cover will be something like 10' from the house to the outer edge? By 14 feet wide right? Are you planning to raise cattle on top of this cover? Why use something so heavy is 4x6 otherwise for rafters? Forget the possibility of the front beam warping, you are going to be putting an awful lot of weight and forward tugging lateral stress on the ledger board you lag bolt into your house framing.

I think you are designing something a bit too robust and heavy.

garya505 08-05-2013 03:44 PM

Quote:

Originally Posted by kwikfishron (Post 1224294)
You live in a kiln. You could buy the green, store it out of the sun for a couple months with good air circulation and there ya go.

Actually we're in our short rainy season now, so I'd have to wait a bit longer.

I could buy the cheap green stuff, twice as much as I need. Then wait until it's dry and sell the ones that are too warped for firewood. :)

garya505 08-05-2013 03:52 PM

Quote:

Originally Posted by sdsester (Post 1224298)
I always used dry lumber when budget allowed.

I will say up front I miss the smell of building things out of kiln dried, a grade redwood heartwood. However, I am curious your adversion to a nice, exterior glue lam beam though? Perhaps you have only seen tacky ones? They come in all wood types you know.

I am guessing your cover will be something like 10' from the house to the outer edge? By 14 feet wide right? Are you planning to raise cattle on top of this cover? Why use something so heavy is 4x6 otherwise for rafters? Forget the possibility of the front beam warping, you are going to be putting an awful lot of weight and forward tugging lateral stress on the ledger board you lag bolt into your house framing.

I think you are designing something a bit too robust and heavy.

My understanding is that with glulam there are a lot of restrictions about where you can put fasteners. No?

14 feet wide by 11 feet deep (from the house). The beam will be at 10 ft so there will be a 1 foot overhang. I've run all the numbers for 2x6, 4x4, and 4x6 rafters, and any would work with the right spacing. I have to design for a 10 psf dead load and 20 psf snow load to meet city code. Beyond that I'd like it to have a "beamed" look rather than just ceiling joists (if that makes sense) so 4x4 or 4x6 is preferred for that reason.

garya505 08-06-2013 01:49 PM

I plan to have 4x6 rafters bearing on a 4x6 ledger (on the house) on one side and on a 6x8 beam on the other side. The rafters will be lag-screwed through the top of the rafter in to the ledger and beam. The roof slope is 1/2" in 12". Do I need to cut a bird's mouth on the rafter? IRC says I need a 1.5 inch bearing length, which I'm not going to get without the bird's mouth, but I've heard that you don't need it with a 1/2 in 12 slope.

garya505 08-14-2013 12:33 PM

I found a 6x8 18" DF #1 at a local lumber yard. The guy said it's been sitting outside (covered) for a couple of years and they haven't sold it because one end (about 1 foot of it) is a little deformed. I'm thinking this is perfect if I can get a good price on it, as it's totally dry. I only need a 14 footer, and I can just cut off the end(s).


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