OSB walls?

[K0k0shka]

@Gray Farms How do you keep the rats out then, if your coops have OSB walls?

 

[Gray Farms]

I keep rat poison blocks out all the time. Under the coops and outside the pens where the chickens can't get to them.

 

[Folly's place]

Our rats that year killed three nice bantam pullets before the bait got them all. Don't ever think that rats are okay!!! And, weasels can enter through any opening big enough for a rat.
Sooner or later, every possible predator will show up.
Mary

 

[aart]

I'd opt for and exterior grade plywood over OSB.
If you do use OSB go for a quality paint(and prep) rather than a stain.
There so much glue in OSB stain won't soak in so well.

Tho my shed door has OSB glued to a standard solid wood door.
Been here since I bought that place 20 years ago,
and it's a bit 'shaggy' but still holding up with no paint or stain.

 

[wyoDreamer]

Most of the OSB that I see out there is only Exposure Rated 1 - which means limited exposure to inclement weather. There is OSB that has a higher exposure rating, but I don't know where to get it. The problem with OSB is that it absorbs water more quickly and dries out slowly - thus rots faster than plywood. They have improved OSB by soaking the wood fibers in wax resin to make them more water-resistant.
Tests have shown that it is structurally stronger than plywood - compare up to 50 layers of wood fibers (OSB) to 4-7 layers of wood laminate (plywood) - more wood fibers matted together is stronger.
OSB is wood fibers mixed with a wax resin and glue and compressed into a sheet.
Plywood is layers of wood laminate stacked on top of each other with glue and resin between the layers - compressed into a sheet.

Most important is what you use to seal it with. My parents used a Solid Color stain on their deck, it is only a year old and pealing already. I used a Transparent stain that will not have the solids in it to water proof my chicken tractor. I will have to see how well it holds up. It did soak in a lot of the wood sealant on the first coat and not so much on the second, so I believe it is well sealed.

As long as the OSB is sealed well, it can last as long as the plywood. But if there is a spot for water to get to the sheet, it can swell up, start to flake and cause problems. Keep it sealed and you should be OK.

 

[wyoDreamer]

Good luck with your build.

Check how it is holding up every spring and seal it when it needs it.

 

[RavalliSurfer]

Until OSB gets wet, it's pretty good as a barrier but I also used some scrap construction materials to build my coop.

First..... it's elevated 4' off the ground on 2x6 legs, triangulated and California cornered. The walls are triple thick with plastic shopping bags inside for insulation and a leftover piece of 3/4" marine plywood as the bottom of the coop..... again with a dead air space of 2" again, labrynthine-filled with those shopping bags.

All the interior is faced with 10mm OSB, waxy side inward. I've sealed and painted all the exterior walls with a semi-gloss alkyd enamel for water repellency and the roof is a mono-laminated and cantilevered single piece of exterior grade OSB, covered in a plastic roofing underlay material.... awaiting shingles at this date.

The outside is covered with textured cerracrete skirting and surplus soffet material with built-in louveres from multiple construction sites..

There is no place that a predator can stand upon to reach the coop from the ground and the underside floor being the first line of defense is a lot of trouble for even a 4 foot tall animal to reach in the first place.

Like I said, a bear or a sasquatch might get in..... but by then all bets are off.

Oh yeah..... (edit) the coop is on doubled 2x8 runners so I can move it and the run every once in a while to give the birds fresh grass to munch. In the winter I don't think it's likely to move the coop on top of the snow.... although a coop on sleigh runners might move pretty fast.

 

[Folly's place]

Our three sided run-in sheds are also on skids, and twice one or another of them have BLOWN OVER in strong winds. Once, it landed on it's top! This won't be good for chickens. You can get anchors to drive into the ground, and I'd consider it.
Neither episode involved actual tornadoes, either.
Mary

 

[K0k0shka]

I'd opt for and exterior grade plywood over OSB.
If you do use OSB go for a quality paint(and prep) rather than a stain.
There so much glue in OSB stain won't soak in so well.

The price difference is significant though... This is already an expensive project. I'm just trying to keep it from blowing my budget even more I've been reading about OSB though, and it says it does accept stains and sealants... I guess we'll have to wait and see. If the stain doesn't seem to be doing a good job, I can paint over it with paint at some point. Or maybe even put siding on the coop. As long as it's spaced out in time, like maybe in a year or two, so the cost is spread out more.

Tho my shed door has OSB glued to a standard solid wood door.
Been here since I bought that place 20 years ago,
and it's a bit 'shaggy' but still holding up with no paint or stain.

Oh that's not bad at all! 20 years and nothing on it, and it's just looking shaggy (and not falling apart). I'll take that! My hope is that with treatment, I can prolong its life even more. That's what's frustrating about searching for information on this subject. All the hits are people complaining how horribly it holds up, how it falls apart, but they're talking about completely untreated OSB left out in the elements. Who leaves untreated wood out like that? Of course it's gonna rot and warp and whatever. Doesn't mean the material is poor necessarily... all wood rots outside if untreated... It's just not fair to the OSB

 

[K0k0shka]

Most important is what you use to seal it with. My parents used a Solid Color stain on their deck, it is only a year old and pealing already. I used a Transparent stain that will not have the solids in it to water proof my chicken tractor. I will have to see how well it holds up. It did soak in a lot of the wood sealant on the first coat and not so much on the second, so I believe it is well sealed.

Yeah, I'm trying to figure out the best product to seal it with. I got some solid color stain as well, but it says it's specifically made for waterproofing, and it's a stain and seal combo. I hope that holds up. Decks are tricky though, they get a lot of wear and abuse so I don't want to compare a deck to a coop wall in terms of stain longevity... There are special products for decks, that hold up better to foot traffic.