Metal roofing... do I need to put something else under it?

[ND]

We're in the process of building our first coop. (no chickens yet... gotta get this coop done!)
Over the years, we've saved and accumulated lots of various materials and so this is mostly being build from salvaged/re-purposed materials.
We have some metal barn roofing/siding that was saved when ice took down our horse barn several years ago and had to be rebuilt, so we were going to use this as our roofing.

Do I need to first use plywood over my rafters then attach the metal roofing to that, or can we JUST use the metal straight to the rafters? (like is done in our horse barns and lean-to) We live in SE Kansas, if that matters. A few months of colder weather... some severe, but USUALLY our 'normal ranges' for winter temps are in the 20's and 30's.
Our summer temps can get quite humid and hot-- going on several weeks of 90+ temps with heat indexes up to 120. (great time to build outside, right?)

We're planning a lot of ventilation (hardware cloth) up high under the eaves- so the walls won't be solid up to the roof anyway. (there will also be 4 large windows (hardware cloth) on 3 sides that can be covered all the way or partially in the winter, but be left open the rest of the time.

The building is a 6X9 and will have a 12X40 run...and house 8-10 birds.

Not sure any of this matters as far as the roofing goes, but it might, so I included it!

It's not a problem to line the roof with plywood first, that's is our initial plan, but I just got to wondering if that's a 'waste' of time and materials if it's not really needed?
(of course, my husband has commented that metal alone would be 'too loud' for the birds during heavy rain or hail... however, he didn't seem to mind that for all my horses OR me when the barn was rebulit!

) It can get deafening in that barn...especially during heavy rain or hail... but the horses and I have survived it every time with no ill effects...

Thanks!

 

[R&RCoop]

as long as the metal can reach from one side to the other of a coop then you do not need to have plywood. ie if it is 6' then you can run it that way all the way down to cover up all 9' or if they are 9' then you can run it all the way to 6'. If you have shorter pieces you would need to run plywood first to attach the metal too. Ours does not have plywood and add to the ventilation where the D panel goes up.

 

[patandchickens]

If your winter lows are typically only in the 20s, you MIGHT be ok with exposed metal (i.e the roofing screwed directly to purlins and exposed from the underneath), if you have good enough ventilation and not too awful many chickens in there. The problem you tend to run into, though, is that with subfreezing temps it becomes a condensation farm and you get incurable humidity problems. If you were somewhere colder I'd say for sure insulate or put plywood underneath. As it is, I think it would be pretty reasonable to skip it IF YOU WANT and then wait and see how things are in the winter -- you can always retrofit something, even bubblewrap can help in mild borderline cases.

OTOH if you are worried that you may have humidity problems ANYhow in the winter, or if you are concerned about summertime heat, then it would not be a bad idea to just go ahead and install it over plywood or OSB if you have the materials easily available.

It doesn't really ahve anything to do with whether the roofing pieces are long enough to span the whole roof slope or whether there has to be an overlapping splice. You can do that just fine with bare purlins and no plywood.

Pat

 

[33yardbirds]

I used metal roofing also but I flopped ply wood first then went with 15 lb felt on top of that hung over the sides frnt and bk (drip protection) Then applied the tin. Felt overhang was coniced with 1 x 4. I went this way to keep squirrels from working their way in through the corragated tin. Forgot to mention it is a shed roof not gable roof.

 

[wsdareme]

Save your plywood and just put the metal roofing over the ceiling joists. All of my horse turnouts and our equipment building are this way, and it's how we did our coop as well. Congrats on recycling! We tore down a covered arena and shop from our old place when we moved, and, boy, has recycling all that wood and roofing saved us a ton of money! The chickens sure don't care if their house is made from new or used!

 

[Joz]

Instead of plywood, run 1x2 purlins across the rafters (@90deg) at 2'-0" on center to support the width of the material. Otherwise it could sag between the rafters.

How far apart are your rafters? How wide are the metal panels?

 

[willheveland]

I screwed my metal roof right to the 1"x 6"purlins. But I used that foamboard with foil on both sides in the coop as like a ceiling. The idea is to keep the metal as close to the outside temp as possible. Hope this helps. Will

 

[ND]

Quote:
See, this is why I thought it might just be 'over the top' for the plywood... all of our other outbuildings (for the horses) are just metal nailed to the joists. He hasn't felt any need to put anything else under it on those structures, so I just wanted to make sure that was OK for the birds, too. Obviously, though... horses and birds aren't the same... so just making sure! Sometimes I wonder just how 'over the top' we have to go with certain things... in 'these parts', most people roll their eyes on what we're building for chickens. The vast majority are 'fend for themselves' and to even be enclosed in a 'barn' (that's far from predator proof) is going out of the way for them.

A LOT of our 'reclaimed wood' came from the downed barn, but also a HUGE gazebo that my husband dismantled for an elderly couple. It enclosed a spa- they just wanted rid of it. It was made almost entirely of cedar. The chickens have cedar deck flooring.... too bad it'll be covered in pine shavings and poop!



To answer some other questions ask:

Our metal 'scraps' are 39" wide...and there are some pieces that are only 6' in length, but the majority are 12' long. They'll have to be cut to size.

I'm not sure how wide apart the rafters will be... I think he was talking about putting four of them... across the 9' span. (9' long, 6' wide-- don't ask how it ended up such odd measurements!

It does have a 2ft 'porch' in the front, so the roofing is actually covering 9X8. ) I think, though he didn't start out planning it this way, he's decided to do a shed type roof rather than peaked. We'll find out soon, as we're at that point in the framing now!

Whatever he decides to do, I'm confident he'll do it 'right'. *I* don't know what I'm doing...building wise...but considering he built our 40X60 new barn himself, I'm not too worried about the chicken house.

Just not terribly sure what to tell him is a MUST vs. 'if you want to'...


Recycling is saving a ton of money...but boy, does it ever slow down the process when you're digging through piles for this and that!

I guess it's worth it, though, since the only expense we'll have is the hardware cloth and run fencing. Just.so.slow....

Thanks for all the advice!

 

[ND]

I should clarify... the other structures (horses) have the metal nailed to the purlins on the trusses, not just to the joists. They're much bigger than 1x2 for those buildings, though.