Building coop, type of wood?

[CountryJ510]

I'm starting to plan my coop and wondering for the main part of the structure, should we use pine 2x4s? And I've heard pressure treated isn't good idea. Is that true? I suppose pine ply wood for the outer wall is ok, or no? We are in Colorado so the wood needs to withstanddsome extreme weather. Thanks!

 

[Primo]

In my opinion, any wood that touches the ground should be pressure treated. (legs, base etc) the rest does not need to be. Just prime and paint and it will last many years.

 

[hosspak]

I'm starting to plan my coop and wondering for the main part of the structure, should we use pine 2x4s? And I've heard pressure treated isn't good idea. Is that true? I suppose pine ply wood for the outer wall is ok, or no? We are in Colorado so the wood needs to withstanddsome extreme weather. Thanks!

As primo said, pressure treated on anything that touches the ground or sits on cement. The rest could be plain (dried) pine. Don't use the green lumber they sell, both are premium but the dry is best for priming and painting, cost is about the same. If your going to paint it anyway stay away from the plywoods, they are too expensive. I went with OSB, (oriented strand board) it's about $8.50 a sheet, it's stronger and lighter than PW and because it's mixed with glue then heated and press formed it already repels water very well and takes paint nicely. That's if you want to hold the budget down but if you want the fancy stuff it will cost you, a 1/2 inch sheet of PW runs about $25 at the Depot and goes up from there.

 

[Bear Foot Farm]

There's nothing wrong with using treated lumber, but it's not necessary for the inside or anything not in contact with the ground

For "extreme weather", siding would be a better choice than plain plywood.
"Cement board" is VERY durable and not a whole lot more expensive than wood siding
Here's just one brand:
http://www.certainteed.com/products/fiber-cement-siding

 

[MoonShadows]

Pressure treated is fine for ground contact, but if you don't want to use it look in the phone book for a local sawmill. You might be able to pick up some Black Walnut or Tamarac...both will outlast even pressure treated. I recently bought 12 rough cut Tamarac boards cut to 10" x 2" x 10' for raised gardens. It actually came out cheaper than buying pressure treated from Lowes.

 

[yogifink]

Make sure that the wood that is in contact with the ground is rated to be in contact with the ground. Not all treated lumber is created equally. Treated deck material, if in contact with the ground will rot in less than a year. Take a look here: http://spartanburgforestproducts.com/our-products/treated-wood/levels-of-treatment

OSB absorbs moisture like a sponge, if you are going to use it for an exterior application take care that it does not get wet. Even if you paint it, water will seep into the joints and cause them to swell and weaken over time. OSB is wrapped in tyvek or vapor barrier before siding is applied when building a home. From wikipidea: "OSB panels have no internal gaps or voids, and are water-resistant, although they do require additional membranes to achieve impermeability to water and are not recommended for exterior use." Although there are different kinds of OSB, one of which is coated one one side, the joints and any cut edges are still susceptible to moisture penatration.

Painted T1-11 is your safest bet to use on the sides of a coop and is manufactured to be used in exterior application (no additional siding would be needed). This stuff is thick and sturdy and is in the median price range. http://www.t111siding.net/

You could also use corrugated metal roofing as siding material, secured properly, this will stand up to any weather. However, metal material is a pita to work with sometimes, so make sure you've got the right tools and you wear gloves.

Plain kiln dried 2x4's for wall and roof framing. OBS plywood on the roof covered with paper and shingles. Or, skip the OSB and use furring strips on the rafters and metal roofing. Both are good for hard weather.

 

[Wrooster]

I agree with Yogifink. Use T1-11 and avoid the OSB or use as he describes. Been there, with more than chicken coops.