Rafter spacing recommendation please!

[Lulu-vt]

It’s happening!! But so much slower than anticipated. I guess that’s what happens when you build solo. I have just started the roof. Here is the first rafter. I was just checking placement of it to make sure everything is ok.

Is it ok?

This rafter thing is no joke! From learning how to use a circular saw then learning how to bevel cut and figuring out geometry with my teens to get the slope, rise and angle of the roof

Honestly, I thought there would be more overhang. What do you think? It’s 6” on each side.

Also, how many rafters do I need to make anyways? It’s a 8x12 foot coop. I was planning on every 20” but could I spread them apart even more? I would love to do less!! I’m planning on probably doing a metal roof.

 

[DobieLover]

That's a hell of a steep pitch for a coop roof.
I would lower it to a 5/12. That would extend your overhangs too.

I was planning on every 20”

That's not a good idea. Lumber/sheathing is cut at 4' increments generally. You need a rafter centered at the seam of two sheets of roof decking. I'd space them 24" OC.
Why didn't you lay your subfloor down before you raised your walls?

 

[Lulu-vt]

That's a hell of a steep pitch for a coop roof.
I would lower it to a 5/12. That would extend your overhangs too.

That's not a good idea. Lumber/sheathing is cut at 4' increments generally. You need a rafter centered at the seam of two sheets of roof decking. I'd space them 24" OC.
Why didn't you lay your subfloor down before you raised your walls?

What do you mean 5/12? Sorry, I’m new at this. I made a 90° angle at the roof peak and that’s just what ended up happening. How would I cut the joining angle to make it not as steep?

The floor….i panicked. I bought osb. It was cheap and I realized it wasn’t going to be a good choice. I thought for the future, if I had rotten osb under the wall joists, it wouldn’t make a stable coop. So I decided to put them in after. I know - it’s backwards. I hope it’s ok though. I’m getting the floor put in this week. 3/4 plywood.

 

[StinkyAcres]

What are your plans for winter ventilation and keeping the rain and snow out of the vents? The best place for those vents is in the soffits, which you might want longer overhangs for.

 

[DobieLover]

What do you mean 5/12?

It's the roof pitch. Rise over run. For every X" of run the roof rises Y". With a 5/12 pitch, for every 1 foot of run (12") it rises 5". It's a much more reasonable pitch to deal with.

You would use a framing square to set the 5/12 angle on the ridge end and tail end of the rafters.
And you should also cut a birds mouth for them so they are bearing weight evenly over the top plate.

Do you have anyone with carpentry skills that can help you with this?

 

[Lulu-vt]

What are your plans for winter ventilation and keeping the rain and snow out of the vents? The best place for those vents is in the soffits, which you might want longer overhangs for.

That was my plan - soffits. I was hoping my overhang would be longer. We do get a lot of snow so I needed a steeper roof, but I think I could bring it down a bit to increase the overhang.

 

[5Australorpasaures]

I would also cut your "birds Mouth" for better bearing on your wall top plate. Your 24" OC hook your tape to the top plate and mark at 23 1/4, 47 1/4, 71 1/4 etc. This insures that your 4x8 Plywood breaks half way on the rafter. As DobieLover said, a 5 pitch is a lot easier to work with, especially when you start roofing, also you can use shorter rafter material. If your rafter material is what you show you will have plenty of soffet space.

 

[Lulu-vt]

It's the roof pitch. Rise over run. For every X" of run the roof rises Y". With a 5/12 pitch, for every 1 foot of run (12") it rises 5". It's a much more reasonable pitch to deal with.
View attachment 3904266
You would use a framing square to set the 5/12 angle on the ridge end and tail end of the rafters.
And you should also cut a birds mouth for them so they are bearing weight evenly over the top plate.

Do you have anyone with carpentry skills that can help you with this?

I have you to help me!!! I'm just kidding I built a pole barn for our goats about a decade ago and it's still standing!!
Thank you so much for the diagram, that's really helpful. I am planning on using rafter ties to secure the rafters to the top plate. I could also cut a "birds mouth" into the wood if you think I should have both.

 

[5Australorpasaures]

I have you to help me!!! I'm just kidding I built a pole barn for our goats about a decade ago and it's still standing!!
Thank you so much for the diagram, that's really helpful. I am planning on using rafter ties to secure the rafters to the top plate. I could also cut a "birds mouth" into the wood if you think I should have both.

Framing houses on Hilton Head SC code was birds mouth and rafter ties, "hurricane clips".

 

[5Australorpasaures]

Framing houses on Hilton Head SC code was birds mouth and rafter ties, "hurricane clips".

Also the birds mouth will reduce the nail spliting your material, another little trick, blunt the point on the nail, reduces splitting also.