How big is a 4X8 sheet of OSB???

[MalcolmR]

So I have this lovely plan for a coop in my mind, and start getting it down onto the ground. It will be exactly 8X12, and will be part coop, part wood shed. So I start with some cement blocks, pressure treated 2X6's and all is going very well. In fact I spent a lot of time making sure that my levels were right, that everything was square, and of course that the coop is exactly 12' long.

Off I go to Home Depot to pick up some plywood for the floor. Very helpful store clerk asks me what I'm doing and when I mention a chicken coop he steers me to the OSB pile - much cheaper, just as strong, and easy to work with. Of course, the size of the sheets is the same - 4X8. I load up 3 of them, head for home and after a few more days of thinking about things, my son and I get around to laying the floor. The OSB has tongue and groove cut down the long sizes, so they fit together nicely. But when we get to the end, we find we are about an inch short. Shock, horror, remeasure - it is exactly 12'. What's going on? Eventually I discover that the size of the OSB is measured to the edge of the tongue, not the edge of the actual surface...

In the end I ripped a 1" patch to fill the gap, but why do they do that? I guess the lesson for me is to measure in the store as well as at home, and don't rely on stated sizes! Anyone else fallen into that trap?

Here is a pic of the structure as it is now:

Regards, Malcolm

 

[MotherJean]

Oh, Malcolm, shall we talk about 2x4's that are 1 1/2" x 3 1/2"? It's maddening, for sure, especially for us non-carpenter DIY'ers. My Dad worked in a plywood mill for 35 years. In case you don't know, th SB in OSB stands for "strand board" - it is made out of the wood scraps (chips) that remain after peeling the logs for plywood veneers. It's all held together with glue, compressed, and kiln dried. The downside to OSB is that is can soak up water or the moisiture present in a humid climate causing it to swell, warp, or even delaminate. To protect it you should wrap your building in a moisture barrier plastic like Tyvek before sheeting it with siding. If you're just planning on painting it (no siding) I recommend a good oil based primer to help seal it both inside and out. Top coats can be water based latex, but the primer should be oil. Maybe this was more information than you ever wanted to know

If you were just wanting to vent - just ignore the foregoing. I'll be happy to meet you at your local Lowe's and we'll go see if can insert a slightly less than 4x8 sheet of OSB up the backside of that sales clerk

 

[MalcolmR]

Thanks MotherJean! I'll meet you at the store about 3 this afternoon, okay?

Thanks for the advice about the sealing etc. I intend to have the place well sealed, sided etc, but at the same time I am beginning to wonder if I should pull that OSB up and exchange it for decent exterior plywood while I still have a chance. I hope this building will stand for many years, and I'm using good quality stuff everywhere else. It would be terrible if the floor fell out in a year or two and I had to take the whole thing to bits to replace it - whereas now it would just be a matter of removing flooring screws and,of course, spending some more money... Hmm, maybe I'll start a new thread to ask that question.

Regards, Malcolm

 

[Hillsvale]

looks good Malcolm, I would use the OSB and seal it as mentioned... its just when the OSB is unsealed and left to our Canadian weather that your asking for trouble.

Shelley

 

[Dar]

I have OSB for my floor and always have.. I coated BOTH sides and all the cut ends with an oil STAIN. Stain will penetrate the wood better and provide longer protection. the floor of my coop is also raised off the ground to allow air flow under the coop so there is no trapped moisture

 

[MalcolmR]

Ah sealing...

Thanks for your comments. I guess I'll be pulling it up either way - either to replace or to seal... Best to do it now rather than later!

Thanks a lot, Malcolm

 

[MotherJean]

Yup, oil stain is good, too. I wouldn't tear it out. Most new home construction uses OSB sheeting for the exterior walls and the builders wrap it in barrier paper like Tyvek. It's a fine lower-cost substitute for exterior grade plywood, you just need to take a little precaution to protect it from water. Looks to me like you have a great start there. I'd just keep on keeping on. How about putting a stain/sealer on the floor and then go dumpster diving at a nearby home construction site for scraps of Tyvek for the walls?

 

[Dar]

I went to Home depot, and Home hardware and to canadian tire and went to their mis tint section of paint and bought 50 gallons of oli based stain in all different colours and mixed them all together and ended up with a dark grey... but i used mistinted stain... saved me a bundle