K0k0shka

Crowing
Premium Feather Member
Jul 24, 2019
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Boston Area, MA
My Coop
I'm in the process of building my first coop. After reading a lot about materials and comparing cost vs performance, I decided to use OSB for the walls, and no siding. I read that it was comparable to plywood in every way, but much cheaper. I read about people using it on coops and recommending it. I was planning on painting all sides of the OSB (and the edges) with BEHR Premium Waterproofing Stain and Sealer. It's advertised as performing better than paint, because it absorbs into the wood and protects it better, as opposed to sitting on top of it like paint and peeling/chipping eventually. I'll caulk the seams between the OSB boards, too.

Now, I was feeling all good and accomplished with my plan, and then I happened upon some threads on here and another forum saying that I shouldn't use OSB for exterior-facing walls at all... that it's gonna warp, mold and fall apart... and I'm having serious doubts. To be fair, the most critical thread was very old - from 8 years ago - so who knows, maybe they make OSB better these days? Also, people criticizing it are saying that it won't last long untreated, but they don't seem to take into account treated (painted/sealed) OSB. I found other comments from other folks who have used OSB, painted it well, and it's been doing fine.

I already bought all my boards and stain and everything...

Please tell me your honest and, ideally, experience-based opinion! Given my plan to seal it well, do you think OSB could work? The coop will be raised off the ground sitting on cinder blocks, there will be no wet tall grass or shrubs around it. The roof will have metal roofing panels on top of an OSB roof board (with a tar paper underlayment) and will have 6 inch roof overhangs, and every surface of OSB everywhere will be sealed.
 
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WallyBirdie

Songster
Aug 2, 2019
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I'm in the process of building my first coop. After reading a lot about materials and comparing cost vs performance, I decided to use OSB for the walls, and no siding. I read that it was comparable to plywood in every way, but much cheaper. I read about people using it on coops and recommending it. I was planning on painting all sides of the OSB (and the edges) with BEHR Premium Waterproofing Stain and Sealer. It's advertised as performing better than paint, because it absorbs into the wood and protects it better, as opposed to sitting on top of it like paint and peeling/chipping eventually. I'll caulk the seams between the OSB boards, too.

Now, I was feeling all good and accomplished with my plan, and then I happened upon some threads on here and another forum saying that I shouldn't use OSB for exterior-facing walls at all... that it's gonna warp, mold and fall apart... and I'm having serious doubts. To be fair, the most critical thread was very old - from 8 years ago - so who knows, maybe they make OSB better these days? Also, people criticizing it are saying that it won't last long untreated, but they don't seem to take into account treated (painted/sealed) OSB. I found other comments from other folks who have used OSB, painted it well, and it's been doing fine.

I already bought all my boards and stain and everything...

Please tell me your honest and, ideally, experience-based opinion! Given my plan to seal it well, do you think OSB could work? The coop will be raised off the ground sitting on cinder blocks, there will be no wet tall grass or shrubs around it. The roof will have metal roofing panels on top of an OSB roof board (with a tar paper underlayment) and will have 6 inch roof overhangs, and every surface of OSB everywhere will be sealed.
I used t1-11 for the exterior, OSB for interior, and shingles on the roof.
 

Folly's place

Enabler
9 Years
Sep 13, 2011
21,226
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southern Michigan
My coop walls are T-111 over either plywood, siding, or OSB, so two or three layers thick.
To your comment, it might hold up with excellent care, but it won't keep many predators out without extra defenses.
A few years ago during a rat infestation here, one little rat chewed a big hole through the OSB overnight. She stuck her head out at me in the morning with a smile on her face! Twelve hours, and a 3" diameter hole!
Mary
 

K0k0shka

Crowing
Premium Feather Member
Jul 24, 2019
1,538
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Boston Area, MA
My Coop
Wow, that's one determined rat! Rats can chew through regular wood too, though. Might be easier with particle boards like OSB, but I guess no wood is really safe. When I was growing up we had mice chew through tin barrels to get to the feed grains on the farm. Is there anything truly rodent-proof?

Also, you say it won't keep predators out, but the example is of a rat. A rat is not a predator, it's just a pest. I won't keep chicks in there, just adult hens or at most, pullets... Would a rat be truly a predator and eat my pullets? The true carnivorous predators that eat chickens don't have wood-gnawing teeth... Would they be able to chew their way in?
 

Gray Farms

Conserve Heritage Breed Livestock
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Apr 11, 2016
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NW Missouri
My coops are OSB walls. Painted every other year on the outside, no paint on the inside. I use Rustolium brand heavy duty oil based enamel paint. It penetrates and coats good. Plywood will last longer but OSB is much cheaper.
 

Gray Farms

Conserve Heritage Breed Livestock
Premium Feather Member
Apr 11, 2016
13,892
18,361
572
NW Missouri
Wow, that's one determined rat! Rats can chew through regular wood too, though. Might be easier with particle boards like OSB, but I guess no wood is really safe. When I was growing up we had mice chew through tin barrels to get to the feed grains on the farm. Is there anything truly rodent-proof?

Also, you say it won't keep predators out, but the example is of a rat. A rat is not a predator, it's just a pest. I won't keep chicks in there, just adult hens or at most, pullets... Would a rat be truly a predator and eat my pullets? The true carnivorous predators that eat chickens don't have wood-gnawing teeth... Would they be able to chew their way in?
Rats will absolutely kill and eat chickens. Racoons can dig/claw through OSB if they are determined to get in.
 

K0k0shka

Crowing
Premium Feather Member
Jul 24, 2019
1,538
3,208
267
Boston Area, MA
My Coop
My coops are OSB walls. Painted every other year on the outside, no paint on the inside. I use Rustolium brand heavy duty oil based enamel paint. It penetrates and coats good. Plywood will last longer but OSB is much cheaper.
Glad to hear, thanks. Do you repaint because it's wearing off and it starts to show, or just in case?

Rats will absolutely kill and eat chickens.
:eek: Full grown chickens??
 

Gray Farms

Conserve Heritage Breed Livestock
Premium Feather Member
Apr 11, 2016
13,892
18,361
572
NW Missouri
Glad to hear, thanks. Do you repaint because it's wearing off and it starts to show, or just in case?


:eek: Full grown chickens??
I repaint just to keep a good coat on. It looks nicer to me freshly painted, though I doubt the chickens care. Sometime I do it every three years or four "very much dislike painting". It gets some wear from sun, ice, wind, chickens pecking a strip off, and just the wear of time. That heavy oil based enamel is really good paint. My oldest shed is getting new OSB this year its about 15 years old and the OSB is pretty much shot.

Yes, rats can with out a doubt kill full grown chickens. They are just as dangerous as a mink or weasel. Maybe more so as there is usually more than one. Though they are easier to kill because they'll eat the rat/mouse poison.
 

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