I want to extend this porch out another 8 feet and convert the current shed roof to a gable roof. Is there a framing genius lurking here who can tell me how to make it happen? The conceptual image gives an idea of what I'm trying to accomplish with the porch. See attachments.

Michael

If a gable roof was built , such that it superimposed the existing shed roof then its run or width ( presuming the rise/run is the same as the main body of the roof) would would likely make the ridge higher than the original ridge which it would be perpendicular to. At least that's the way it looks , without knowing the dimensions.
Your question implies you do not know how to build a gable roof. To build one onto that existing structure is a job for an experienced framer who is comfortable with the math.
If you are not familiar and comfortable with advanced roof framing in the first place , this particular job is a very risky place to start.

One way to get the job done if you are married to the idea of doing it yourself is to order a truss system. Roof truss companies are usually pretty good about doing the calculations .
You would need to supply an acurate drawing that demonstrated the rise / run & demensions of the existing roof , the proposed new framing walls or beams running perpendicular to the front of the house. An existing framing plan .Then the Truss co could engineer a series of trusses that would step up the exisitng roof appropriately

By the looks of your roof,you have a truss system in place now... to alter the existing

Trusses to change the roofline would definitely be a major undertaking like nwptsailor said.

Cutting all of the trusses and making them feasible to work under your gable would be

Very expensive. Check and see if there are trusses there now... it would be better if there

Weren't. Kellyw.

There are no trusses. This is a stick-built roof. The roof has a 5/12 pitch. The perimeter of the house is 26x56. It was constructed per FHA (Farmer's Home Administration) specs in 1969 (2x6 joists and rafters).

Several other contractors on the web have looked at the photos. Most have concluded that a gable roof cannot be placed over the porch without entirely removing the shed roof portion from the middle of the house and starting over with the framing. I've concluded the same thing, but was hoping that maybe someone would offer an idea that the rest of us have overlooked.

Thanks for the responses,

Michael

Your image of the new roofs shows you what has to be done.Remove shingles,plywood,cut

Rafters,re rafter,using trusses where you can sheet and paper. Find 7 days of no rain, and

A carpenter and a helper can have the roof off and dried in... it will enhance the looks of

Your home... good luck kellyw

I'm Just about to finish the roof on my shed. Beings that this is the first roof I've ever built I can see rookie mistakes in it. The roof covers an area 12x16 so I felt it was a good beginner project to see if when we build our house if I would attempt it. The rafter span was 6 foot 6 inches so using 2x4s I spaced the on 24 when I went to lay the OSB sheets I found quite a few mistakes in my spacing and not cutting the birdsmouth correctly left me sitting a little high in a few spots. From what I've done Id say any rafter that would be over 10 foot I would call a truss company to deal with the cuts. The math and calculations aren't the hard parts you have to get past it's in making the cuts correctly. I searched the internet for how to make trusses and could not find anything that wasn't confusing. If you want to do the project yourself the best little resource I found was "The Little Blue Book" sold at Lowe's and probably Home Depot if it wasn't for thoroughly reading that book I would have started the projected by wasting a lot of 2x4s till I got the first rafter correct. By the way once the first rafter is cut correctly the rest is easy street since that becomes the template for all the others unless you have a funky roof. Good luck if you haven't started this project.