Roofing question

[MalcolmR]

Just started my new coop today It'll be a long process, but I need to know the details of the roof before I go much further,

The structure is 8X12, but at least half of it will be used for people (me) and I need to have at least 6' of head room. I am building a single slope (pent?) roof, and my current plan is for it to be 7'2" of headroom in the front, sloping down to 6'3" at the back. This gives a pitch of just 7 degrees. If drop the back a little more to 5'9" (which will be just about okay for me), that increases the pitch to 10 degrees.

My wife tells me that there is a formula for minimum requirements which includes the angle of pitch as well as the minimum spacing of rafters (I was planning on 24"). Maybe I am being a little picky in this, but does anyone have any advice? We are in a fairly high snowfall area, and get a lot of wind and rain as well!

Thanks, Malcolm

 

[RocketDad]

Ignore degrees.

Roofing slope is described as feet-of-rise per feet-of-run; ie, "10 in 12" or "4 in 12". Four in 12 ( or 4:12) is the flattest residential roof that isn't a "flat roof." Sloped roofs can be shingled, flat roofs need to be, well, poured with hot tar. Ick.

Plumbing and gutters need to be 1/4" per foot minimum slope, but you want rain and snow to leave the roof quickly to minimize time to find leaks.

 

[RocketDad]

As for rafter spacing, look at the numbers printed on your plywood. Most plywood (and OSB) is rated for residential housing code, with 16" stud or joist spacing required for walls and floors, but 24" allowable for rafters/trusses depending on the sheathing used. Look for a "16/24" printed on the plywood, and you'll see what I mean.

Really, though, for a coop you could use a lower thickness of plywood than required for a house and be fine. Not that I did. I built my coop like a house. A really study, well insulated, passive-solar house. Do the chickens care? No. Does rocketmom care? No, she wishes the coop cost less. But I care, because that's the kind of carpenter I am.

Have fun. Don't take it too seriously. "It's just a chicken coop."

 

[MalcolmR]

Thanks RocketDad! Those are valuable comments, and expose my utter amateurishness... But I do want to get it right. I'll have a closer look at the OSB that I have and see if I can find that 16/24. I'm going to be spending more on it than I would like, but I'm hoping it will be well built in the end. Thanks for your input.

Malcolm

 

[SillyChicken]

Thats the same thing I had to keep telling my DH, we tend to "overbuild" things...It's ok honey, it's just a coup!

I think you can get away with a lesser pitch to the roof if you use metal. Minimum pitch for shingles is 4/12 pitch... (4" down for every 12" across) The steeper the pitch will move snow/rain off faster and lessen the load and leaks, better if you use thiner products 1/2"osb, 24"oc,, 2x4 rafters etc... more pitch would be better for the span.

 

[elmo]

I think it depends on your roof material, too. The polycarbonate panels I used did have specific slope recommendations. Here's another suggestion, though. I wish I'd built in more overhang on roofing my run. Without overhang, the rain blows in from the side and wets the first two feet all around the perimiter inside the run.

 

[lildinkem]

One of my coops I am using the indestructable force of a 1967 Chevy Truck hood. lololol

 

[enggass]

I was planning on going with the TuffTex Corrugated Panels. I think my pitch will be 2:12 (6 foot span going from 7' on one side down to 6' on the other).
Won't that be fine for rainfall? Any snow we get I plan on sweeping the roof anyway. Snow will stick to any pitch anyhow in my experience.

Steve

 

[MalcolmR]

Hmm - lots of interesting points...

I am not too sure about roofing material yet. I have some shingles left over after recently redoing the house, but I also have a friend who has some metal roofing left over from another job. It is just a coop, but it has to look good too, and part of it will be for humans. I agree with Steve (my next-door neighbour in Maine) that 2:12 really should be enough for rain, and that snow tends to stick anyway. Maybe I'll revert to a traditional pitched roof after all - a little more work building the trusses, but maybe better in the long run. Decisions, decisions!

Malcolm