Link detached (attached)side return extension roofing ideas?

[was8v]

Our garage alone separates us from our neighbour. The far garage wall is a party wall that continues behind it. Garage has a pitched roof parallel to the house.

Like this:



To the rear of our garage is 10' x 8' dead space thats always in shadow as its trapped between the houses. We have a shed there at the moment.

Like this:



We could do with a small utility room and downstairs loo.

The neighbour (at the moment) is happy for us to use the rear portion of "their wall" (the part of which where our garage is "party" at the moment, this "party" bit will extend to all the lower floor) to put a roof on and build an end wall to enclose the space with a sliding patio door on the end, flush with the two houses.

I'm doing this on a strict budget as we aren't going to be here too long.

I'm struggling with what to do about a roof:

A) Can I put a flat roof extending back? (will probably leak in future)
B) A pitched roof to our side with a valley on the party wall side?
C) Change the rear pitch of the garage roof (can you have a roof with two different pitches?)
D) re-roof the garage and extension with a new pitch £££

Do we need cavity trays? Our houses are cement rendered unlike those photos.

[Eddieslofart]

A flat roof is perfectly feasible, and using quality materials will see you out.

And yes, cavity trays would be the correct way to detail the abutments.

I prefer type E trays as only one course of brick needs to come out to fit.