Porch roof

[wharton]

I am building a screen porch with a roof over my rear lanai. The house where I have to attach the roof only has a fascia board to connect to. I don't believe that will be strong enough to support the roof in high winds. Can anyone give me some help? Thanks.

[Rich]

What type of roof are you going to build - single pitch (shed type), gable, or hip? How long will the rafters have to span?

[Tom R]

In the 'simplest' of scenarios, if your existing roof is sloping towards your porch area, and your proposed roof will be sloping in the same direction, (but probably with less pitch), you would remove the fascia board, cut back your shingles and plywood (so the cut-off line is above your back wall), then slide your new rafters alongside your existing ones (with full 'bearing' on top of the wall), attach them to the wall and your existing rafters, sheathe from your cut-off point, and run your shingles from the bottom up until you 'underlap' your old ones.

[Rich]

The roof for the house slopes down toward the porch. The new porch roof is a "shed" type roof dropping about 1" per foot with 12' rafters.


In that case what Tom R is suggesting would work perfectly. If what you want for a slope has the outside of the porch too high you can either steepen the pitch of the new roof or attach a ledger board to the wall and hang your rafters from there. The ledger board would need to be attached directly to the studs, in the best situation, with lag bolts. This gives a good place to put flashing behind the siding and over the roofing.

[wharton]

Thanks for the response. I sounds like my solution is to take off the fascia board from the eave of the house and attach a 2 X 6 ledger board to the current house rafters with hurricane straps then attach the new porch rafters from this ledger board with the hurricane hangers. Thnk that might work?

[Rich]

You'll only need a ledger board if you are going to lower the new roof down the wall from the existing roof.. so if there is a step between the two roofs then you'll need a ledger.
If it will be a continuous roof (no drop) then you can do exactly what TomR suggested - no ledger board needed.

[wharton]

Thanks for the help.