I am wanting to add a roof (shingled) over my patio. Can I have a span of 16' with 2x12's and 16" centers?

Question

my patio is 25' across and 15' deep - i'd like to have a shingled roof put over it. I would like to use the 2x12's connected to the house at 10' in height and go out 16' (1' over hang) where it would be 8' in height. Is this 15' span too much?

Answer 1

I did almost exactly as you want to. Mine is 25 x 12. Don't worry about the pitch. I used shingles. It's only a patio shelter. Mile is holding up well.

Answer 2

16' is too far for 2*12's. especially at such a flat pitch. if you live where it snows, it's even worse. use LVL's or laminated I-joists. it will cost you more, but trust me, you would be really pushing it with 2*12's. also, any pitch under a 2/12 (2" across for every 12" up) is too flat for shingles. go with rolled rubber roofing. at that pitch, no one will see the roof anyway. good luck with your project!

Answer 3

It might be ok, BUT you really need to talk to the building code official in your area to find out exactly what is required by code.  You will probably need a building permit also.  Check first as to what is required to be up to code and follow their instructions to the letter.   If it is not done properly you will be told to take it down. If it should happen to fail, someone gets hurt, then you will be held responsible legally and financially. If something were to happen it could also damage your home. Better to be safe than sorry.

Answer 4

2x12 will span what you need, the placement of two rows of solid blocking or criss-sross 1x bridging is recommended. The problem you will have is that the pitch of the roof will be 1.5/12  it is not recommended to use shingles on any roof less then a 3/12. You will need a built up or rolled roofing ie. hot tar roof. If you do use shingles use Grace Ice and snow shield, a rubberized underlayment. and instead of 4" to the weather go 3.50" max. even though it is only a patio you do not want it to leak and you want it to last as long as possible. If you close in the underside  make sure you drill a few 7/8' holes in the high side of the rafter for air flow. and use roof and soffit vents. this will also prevent premature failure of the shingles.