How to extend a roof that is part of a valley roof

Hubby and I would like to enlarge our porch by adding onto the back of it. We’ve hit a little snag however in trying to figure out how to roof our extension. Would very much appreciate any instruction on what to do.

I hope the picture shows up and isn’t too large

It’s less than 100% clear what you’re trying to do. Are you planning on extending the addition out from the middle where that large window opening is and the valley would be coming down on the right side? That’s what is looks like but a bit more detail would be helpful. How long, coming out from the existing structure, is the addition to be? Have you decided on the pitch of the addition roof? Is the addition going to be a flat roof, gable or half hip?

Yes, the porch is that large window where the screen has been pulled out. We would like to extend the porch about ten feet from its present back wall. Our first thought was to add a 1/12 pitch shed roof by attaching it to the underside of the present porch roof, however there are a couple of problems with that idea: (1) since the ceiling height of the present roof is only about seven feet, by the time we get ten feet out, the ceiling height would end up being less than six feet; (2) we would end up with some dead space between the existing garage (where the door is) and the new porch, which I can only imagine would cause many headaches whenever it rains or snows, so we’ve decided we don’t want to do that.

FYI, the garage roof is roof trusses. The overhang at the end of the garage roof is eight inches. What can we do to eliminate that gap that would be created due to that overhang and also be able to have a decent ceiling height at the new back wall of the porch.

cut rafter tails over hang even even with existing out side wall ( 3 sides looks like ) install header 8’ 3" high attach to wall

Is there anything we should do to the rafter tails after we have cut them, such as attach them in some way to the new roof rafter that we would put right next to that wall?

cut 1 sheet plywood into 3rds 16’ liquid nails glue 2 pcs together rafter tails must be cut strait nail 2 8s per tail top bottom plywood keep tails from spliting set header at hight bolt or screw set rafters install plywood when you get to tie in remove existing 2x8 ply ??? install plywood from old to new should transition close

I’m sorry, could you explain a little further. I’m having trouble understanding your meaning.

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