Can I skip plywood under metal roof?

[Lulu-vt]

I am almost done building the rafters. I have purlins. I would really love to skip out on the cost of plywood if I can just use a metal roof. We did this for our goat barn before I knew any different.
From what I’ve read, the metal can collect condensation and drip. Really? Could I use some sort of felt underlayment without the plywood? The coop will have soffit vents (covered by hardware cloth). I know it’s louder but do chickens care?
I live in Vermont. It can get cold and snowy (not as much as it used to though). Could I get away with no plywood?
I’m building solo and plywood is hard for me to manage. Also I’m way over budget!

 

[GlicksChicks]

I am almost done building the rafters. I have purlins. I would really love to skip out on the cost of plywood if I can just use a metal roof. We did this for our goat barn before I knew any different.
From what I’ve read, the metal can collect condensation and drip. Really? Could I use some sort of felt underlayment without the plywood? The coop will have soffit vents (covered by hardware cloth). I know it’s louder but do chickens care?
I live in Vermont. It can get cold and snowy (not as much as it used to though). Could I get away with no plywood?
I’m building solo and plywood is hard for me to manage. Also I’m way over budget!

What I have is a metal roof and there is just one support beam over the middle of the coop. The roof holds up perfectly well to weather.

Plywood is not perfect either. If water can condensate and drip as some people say (I have never had this experience with my coop) then that water would be trapped between the plywood and metal and then you would end up with soggy plywood. And plywood can mildew, unlike metal.

 

[DobieLover]

I have never had this experience with my coop

You are in Dallas. You will never ever experience a northern winter cold.

If water can condensate and drip as some people say

It doesn't condensate on the wood like it will on metal. Metal is a thermal conductor. The wood can have a coat or two of exterior grade primer/paint on it and will hold up just fine.

@Lulu-vt, if you were putting the roof over an unheated shed with nothing in it that was generating moisture all night, it would be fine over just purlins. I would not skimp out on building properly for housing poultry. You WILL have condensation on bare metal and yes, it will drip on the birds and yes, this can cause severe frostbite.

Unless you are building a properly designed Woods-style coop, which you are not, install the plywood to keep condensation from forming. The plywood will still need the felt paper over it for a moisture barrier from rain. You can't install metal roofing with just felt paper under it. The felt needs to be attached to something. It can't just be flapping around on purlins.

 

[Lulu-vt]

You are in Dallas. You will never ever experience a northern winter cold.

It doesn't condensate on the wood like it will on metal. Metal is a thermal conductor. The wood can have a coat or two of exterior grade primer/paint on it and will hold up just fine.

@Lulu-vt, if you were putting the roof over an unheated shed with nothing in it that was generating moisture all night, it would be fine over just purlins. I would not skimp out on building properly for housing poultry. You WILL have condensation on bare metal and yes, it will drip on the birds and yes, this can cause severe frostbite.

Unless you are building a properly designed Woods-style coop, which you are not, install the plywood to keep condensation from forming. The plywood will still need the felt paper over it for a moisture barrier from rain. You can't install metal roofing with just felt paper under it. The felt needs to be attached to something. It can't just be flapping around on purlins.

Ok. Noted. Thanks. Off to buy plywood.

 

[aart]

The coop will have soffit vents (covered by hardware cloth).

Did you get your rafter plans adjusted to provide a larger roof overhang?

I live in Vermont.

Here's how to add your general geographical location to your profile.
It's easy to do, and then it's always there!

 

[Panamom]

I am almost done building the rafters. I have purlins. I would really love to skip out on the cost of plywood if I can just use a metal roof. We did this for our goat barn before I knew any different.
From what I’ve read, the metal can collect condensation and drip. Really? Could I use some sort of felt underlayment without the plywood? The coop will have soffit vents (covered by hardware cloth). I know it’s louder but do chickens care?
I live in Vermont. It can get cold and snowy (not as much as it used to though). Could I get away with no plywood?
I’m building solo and plywood is hard for me to manage. Also I’m way over budget!

I had a coop with a metal roof. I live in Florida where weather isn’t much of a consideration, except for hurricanes. I have a good friend with a tall coop with a metal roof. Metal can make the coop very warm if in direct sunlight. Otherwise I can’t think of any kind of problem with it.

 

[StinkyAcres]

Ok. Noted. Thanks. Off to buy plywood.

Did you end up returning the OSB?

 

[FlippinFancyFeathers]

You are in Dallas. You will never ever experience a northern winter cold.

It doesn't condensate on the wood like it will on metal. Metal is a thermal conductor. The wood can have a coat or two of exterior grade primer/paint on it and will hold up just fine.

@Lulu-vt, if you were putting the roof over an unheated shed with nothing in it that was generating moisture all night, it would be fine over just purlins. I would not skimp out on building properly for housing poultry. You WILL have condensation on bare metal and yes, it will drip on the birds and yes, this can cause severe frostbite.

Unless you are building a properly designed Woods-style coop, which you are not, install the plywood to keep condensation from forming. The plywood will still need the felt paper over it for a moisture barrier from rain. You can't install metal roofing with just felt paper under it. The felt needs to be attached to something. It can't just be flapping around on purlins.

 

[FlippinFancyFeathers]

Please note that DobieLover said that "metal is a thermal conductor". In other words, it retains the heat. Therefore, even corrugated roofing is affected. Part of my house has corrugated roofing and that section always feels like a furnase during the Summer months so imagine what it does for your chickens! Of course, the opposite is the same for the Winter months. I'm renting so I have no say in the matter otherwise I'd rip it off and replace it! A neighbour recently, put up solar panels over corrugated roofing. I just rolled my eyes. It just defeats the purpose as they're fighting the heat retained by the corrugated roofing! There electricity bill would be even lower if they had changed to tiles first! I'd never use corrugated or any form of metal roofing for my chickens! Sadly, you've probably already done it by now. Sorry I didn't see this post sooner, but maybe it might help someone else! Good luck!

 

[Ted Brown]

... YOu can't install metal roofing with just felt paper under it. The felt needs to be attached to something. It can't just be flapping around on purlins.

I have a covered run that has rough cut 1"x4" purloins at 16" on center. I used roofing membrane under old tin sheets, installed from the bottom and overlapped 4".

It does not move.