Patio Cover - Need help/suggestions

DIYer

I am new here. Looks like there is a lot of great info and knowledable people. I am planning to build a patio cover. It will be about 11'X20'. It will be adjacent to the house on two sides. My goals are to keep the ceiling as high as possible and make it look "right". The exsisting soffit is at about 7'8". I would rather tie into the roof at the fascia because it looks easier than tieing into the trusses. The soffit is about 1.5' and I figure a 1' overhang past the beam. I was going to use 2 4"X4" posts spaced about 9' apart. I might also put a 4"X4" post at the house so that the exising wall doesn't have to support the weight. I was going to slope on the 11' dimension to keep the span short and to minimize the drop needed. I plan to remove the fascia and tie in 2"X4" joists on 12" centers using joist hangers. Due to the soffit and overhang, the span will be about 8.5' from the fascia to the beam. I figure that I could make the top of the 2"X4" flush with the roof at the fascia. At the beam, I could have the bottom of the 2'X4' at 7'8". This would allow me to keep the ceiling at the current height of the soffit, hence acheiving one of my goals. I would need some flashing or drip edge along the other edge adjacent to the house. Then use joist hangers to attach 2'X4's for the overhang. With this method, I would get about 2' of fall over the 9.5' of new roof. I assume that I can not use shingles and would need to use rooled roofing. My main concerns are the 8.5' span using 2'X4' on 12" centers and the slope of the roof. Another option would be to use 2'X6" joists and just make the celing 7'6". 2" probably wouldn't make a big difference and it would be stronger. Thanks in advance for the help.

bob the builder

Not sure but are you planning on joist hangering 2x4 to the exisisting facia??? Either way you are going to have to take shingles off of exisisting roof so why not just tie it into the house top plate??? I would use a rubber membrane instead of rolled roofing. 2x4's can't span 11' regaurdless of what you decide. Knowing what code says your snow and wind load helps decide what to do for roof...

Bob

DIYer

Bob,
I don't think that I understood your post. I am not in construction, so I don't know all the terms.

I plan on removing the fascia. I assume that there is a 2"X4" or a 2"X6" behing the fascia, but I can add one if needed. If I add on at the fascia (really the end of the trusses), why would I need to remove shingles? What is the house top plate? I don't plan on having the 2"X4" joists resting on top of the beam. The 2"X4" span would only be from the fascia to the beam, which is about 8.5' Do you think this is still too long? I called the city and have the information, but it isn't with me at the moment.

Thanks for the help.

bob the builder

Starting with existing house. You have the exterior wall that your trusses are resting on, that is a load bearing wall. Then you have your overhanging trusses sounds like maybe about 1.5 feet away from the house. So when you take off the facia you do indeed see the ends of the truss/rafters. This is not where you want to attach your new structure to. You want to take off facia, and attach your new roof 2' back directly above your exterior load bearing wall assuming it can support the extra weight. You could leave exisisting facia and use posts next to the house but you would need 3 posts running the 20' way. Then a beam attached to all your posts and the roof rafters are supported by beam next to house. One problem with that is the post required would be right in the middle of the walk area, not great. I don't understand the beam 8.5 feet away from the house unless subtracting the distance of your house overhang being 1' 6"??? So if my assumptions are correct you need roof rafters that can span 10' and support your local snow and wind loads, here that is 50 lbs. per sq. ft.

Does any of that make sense???

Bop

DIYer

Bob,
Yes, that cleared up some confusion. I was not planning on running the joists all the way back to the top of the exterior wall. I was just going to tie into the trusses. That is why I subtracted the 1.5'. Is this a bad idea?

On another note. I still don't understand why I would need to remove shingles. Is it becasue of your scenerio of running the joists to the top of the exterior wall?

bob the builder

No your truss/rafter tail cannot support anything, that is why you will need to rip into the roof a little, and while your add it you can add headroom by tieing in higher on exisisting roof.

For removing shingles, when water runs down your exisisting roof and gets to the new roof that is a spot that needs some flashing. The flashing or rubber or roll roofing would run about 2' above the new roof line.

Bob

Teetorbilt

Listen to Bob, he has you going in the right direction.

DIYer

Thanks for the ideas. That is a lot more work than what I was planning, but I see the value of resting the joists on the top of the exsisting wall. How would you suggest tieing the joists up higher?