Lean-to construction questions

[dwcopple]

Plan on building a lean-to awning off the back of my garage.
If I go 12' wide what kind of board should my ledger be? 2x8? I plan on using joist hangers
and how many poles would be necessary? two or three? size? 4x4 or 4x6
rafters should be 2x6 I am thinking and the two crossboards at the top of the beam as well or should those be 2x8's? I am thinking I'd go 8' out from the building so I can use 4x8 sheets for roofing.

 

[SF0059]

Check with your city or county for code in your area. They will typically define the size and spacing of supports. Better to abide by the code and get a permit than to have headaches later when selling the place.

 

[dernp]

You are pretty much bang on. 2 x 8 ledger can be run 12' no problem. Use 2 x 6 for the rafters is ok. I would suggest using 3 - 6 x 6 posts as they won't crack and twist as easily as a 4 x 4. I also like to set the posts so that there would be approx a 2' cantilever (overhang) and also bring the end posts in about 1' from the perimeter as well. This way your rafter span will be about 6' at the most. And your beam boards can be 2 x 6 but 2 x 8 might have a better appearance.

 

[Nick R]

Originally Posted By: SF0059
Check with your city or county for code in your area. They will typically define the size and spacing of supports. Better to abide by the code and get a permit than to have headaches later when selling the place.



This. Get a permit, and find out what code specifies for your area.

 

[dwcopple]

Turns out it will be 10'x8'. I can't do 12' length afterall. So if I did a 10x8 would two posts be enough?

 

[GreeCguy]

Two 6x6 posts should be fine or you can use three 4x4 posts. The main thing you want to consider is the beam spanning the distance between the posts. You could get away with sandwiching two 2x6 boards together with a piece of plywood or OSB between the two boards. That will hold a tremendous amount of weight as you have to consider what kind of roofing you're going to use. A metal roof will be relatively light as an asphalt shingle roof will be heavy.

The advantage of using three 4x4's is that your sandwiched beam will fit perfectly on top of these and if in the future you want to add a wall to keep the weather out you only need to span the distant between 4x4 with 2x4's which will fit perfectly and look nice, (run them horizontally every two feet). A little angle bracing with some scrap lumber is never a bad idea either.