Metal roof underlayment placement

[Krugerrand]

Not sure if this helps but I just attached metal roofing on top of the plywood, and you can get foam inserts to fit along the edges. hope that helps

If you get foam inserts, I recommend that you buy them when you buy the roofing. I tried to go back later and had a hard time getting the inserts that specifically matched the pattern of the roofing. Then, I just went without them all together.

 

[U_Stormcrow]

^^^ beat me to it.
When residential housing uses rigid metal foam under a metal roof, it works like this (from bottom up):

Trusses/Rafters
3/4" Plywood/OSB Decking
Moisture Barrier (usually peel/stick)
Rigid Foam
Purlins
Metal Roofing

For a hen house, that's overkill. Several $ per square foot of roofing.

The next question is WHY INSULATE? 1" of rigid foam has an R-factor of high 4 to low 5. It slows heat transfer, sure, but that's it. R4.7 isn't noticeable. I don't know where you are in FL, but when I lived along the I-4 corridor, that meant part of the year you woke up at 80 degrees, it hit a high around 97, then "cooled off" down to 80 again, repeat, repeat, repeat. In those circumstances, Insulation isn't really helping a well ventilated coop (which is far more important).

I like exposed rafters and exposed purlins well above my bird's heads. So when a water leak inevitably occurs, its visible long before it has a chance to do damage.

Then, if you can, use bare metal - reflects a lot of heat/solar radiation. The relatively thin guage ensures it doesn't hold much heat either, so there isn't a lot of radiant heat transfer to the underside (inside of coop). If you have great airflow and a roof vent, that warm surface will encourage a draw of cooler air from shaded surfaces, up to the roof, and then up towards the roof vent, where it escapes.

Pics from my goat shed.

 

[Cynthia12]

I sometimes wonder what it would be like to wear black without the fur.

..I remember those days...And, Every spring I did a real good brushing out.. a few different times. It looked as though I had sheared a sheep. Here's my last gal with a doodle pup I had for a short time.

 

[mqoh]

..I remember those days...And, Every spring I did a real good brushing out.. a few different times. It looked as though I had sheared a sheep. Here's my last gal with a doodle pup I had for a short time. View attachment 3393061

Pretty girl

 

[mqoh]

^^^ beat me to it.
When residential housing uses rigid metal foam under a metal roof, it works like this (from bottom up):

Trusses/Rafters
3/4" Plywood/OSB Decking
Moisture Barrier (usually peel/stick)
Rigid Foam
Purlins
Metal Roofing

For a hen house, that's overkill. Several $ per square foot of roofing.

The next question is WHY INSULATE? 1" of rigid foam has an R-factor of high 4 to low 5. It slows heat transfer, sure, but that's it. R4.7 isn't noticeable. I don't know where you are in FL, but when I lived along the I-4 corridor, that meant part of the year you woke up at 80 degrees, it hit a high around 97, then "cooled off" down to 80 again, repeat, repeat, repeat. In those circumstances, Insulation isn't really helping a well ventilated coop (which is far more important).

I like exposed rafters and exposed purlins well above my bird's heads. So when a water leak inevitably occurs, its visible long before it has a chance to do damage.

Then, if you can, use bare metal - reflects a lot of heat/solar radiation. The relatively thin guage ensures it doesn't hold much heat either, so there isn't a lot of radiant heat transfer to the underside (inside of coop). If you have great airflow and a roof vent, that warm surface will encourage a draw of cooler air from shaded surfaces, up to the roof, and then up towards the roof vent, where it escapes.

Pics from my goat shed.

Thanks very much for answering my question. Some people recommend it some don't. I already had the ridged foam and thought I would throw it up there anyway. Love the bare look of yours so I'm still conflicted. My metal shed gets hot as hades even when it's open. Thought reducing the radiant heat would be a plus. Thanks again for a very thoughtful answer.

 

[3KillerBs]

My metal shed gets hot as hades even when it's open.

This is why you have to have the correct airflow directly under the roof.

https://www.backyardchickens.com/articles/repecka-illustrates-coop-ventilation.77659/

For ordinary sheds those dinky little rectangular vents and the minimal ridge vent simply don't move enough air.

 

[perkolator]

I went for just metal roof right onto purlins, no underlayment or insulation - all that's overkill for a chicken coop. Maybe paint it white if it's in full sun and you want to reflect some sun/heat

 

[U_Stormcrow]

I snuck out for lunch - rare moment of sun today, but didn't have time to post this. According to my digital thermometer, it was 77.2 degrees outside, light breeze, maybe 3 mph (my guess).

I have two "coops". The first (mistakes were made), my metal roof measured 84.1 degrees in physical contact with the sheet metal. Inside, at roost level (thermometer 6" above roost) I read 77.6 to 77.8, and 4" from the roof underside, I read 78.4, 78.5 just before it exited the roof vent.

The second (pictured above, the goat barn). Same surface temp. Maybe 0.1 higher, it waffled some. Inside was 77.2. 4" from the roof? 77.3.

Hope that helps. One of these days, I'll redo coop one to both expand it and improve the under eave venting,