What type of plywood for roofing do I use?

[silkiechicken]

OSB is really cheap and properly used would probably work well for a coop. However... I spent the extra 300 bucks on plywood vs osb on my small 6x8 coop because OSB it just swells up and doesn't last in the PNW. Of course the technology for making it could be a whole lot better now a days, but I didn't want to use material that might look like the left over OSB sheet bits from the mid 90's that were stored in our dry carport for scrap projects.

Whole houses are made of OSB sheathing, so it can't be that bad if weather tight. Our old house uses no OSB though and if I can afford it, won't use OSB on any new house either. The guy at Lowe's (in Washington) said that if I was building my coop in California, he would say use the OSB and save some money, but because we are not in cali, I'll save more in the long run with 1/2ply sheathing ($13 a sheet). I want to say exterior grade ply was twice that.

 

[KDK1]

1/2" CDX with your rafters no more than 2' OC. I would not use OSB... especially for a roof, it's a totally inferior product.

 

[Haunted Chicken]

Another product we saw was RTD, anyone know what that is? It's $12.57 so it must be better lol, if price is an indicator.

I had planned on painting the OSB in two coats of paint first ( I have about 10 gallons left over from painting my house a few years ago (recycled and cheap, but is holding up great on the house).

But now I'm thinking it wont be worth it, too much rain here. I want this to last a long time. I guess I just need to save up a bit more and do it right.

Thanks for all the comments, it helps.

 

[Haunted Chicken]

Quote:
$36 a sheet, yikes! I might be saving for a lot longer than I thought.

 

[silkiechicken]

The CDX 1/2 inch ply I got from lowes for my roof rafters set 16OC were only like 13 a sheet. But, I plan on finishing the roof with felt, dripline, and shingles to protect it.

This

For the floor I used 3/4 inch exterior grade ply with 16 in OC 2x6 flooring....because I hate soggy floors and only planned on painting the floor.

this

Used this for siding and made sure to nail through the thicker boards, not in the cracks for structural reasons. Did not use sheathing under the t1-11 all wood ply. That cheap smart side stuff I would not trust if using it structurally and want it to last. It is thin, OSB style backing, and I'm pretty sure it is meant to go over osb or other sheathing first.

 

[Haunted Chicken]

Quote:
Wow, lot's of great info, thanks. I'll be felting and shingling as well. Not sure what a drip line is, I'm guessing not a gutter.

(Not sure if I mentioned this is for my run. I bought a used coop which we are beefing up a bit....leaks like a sieve right now

It will go under the run so the run roof will really be covering both)

 

[silkiechicken]

I'm probably using the wrong words for coop materials since I'm a complete 100% novice. By drip line I meant I was going to get that metal flashing to put at the edges of the roof so water can drip off and not seep up under the shingles/felt. I used a 4 in 12 pitch as that was the recomended minimum I found for shingles without use of ice/water barrier stuff.

 

[Haunted Chicken]

Quote:
Ahhhhh I see, I'll have to look into that too. Thanks

 

[florida lee]

I use ONDURA from Lowes..on all my sheds and coups.....much lighter than shingles......about $20 ea. Each sheet covers an area of about 44" x 72". Just use 2x4's for rafters and 1x4" for purlins..needs special nails for about $10/bx. Easy to work with and easy to repair.

 

[Mac in Wisco]

OSB is perfectly fine when it is used for what it's made for, underlayment. It is meant to be used underneath other flooring, roofing, or siding materials. You rarely see a new house built anymore that doesn't use OSB as a decking material. OSB is extremely poor as an exposed siding material as many here have found out. It takes paint poorly, and readily absorbs water.

If you do the shingled roof correctly, with roofing felt and steel drip edges in addition to the shingles, OSB is a good, inexpensive material.