There is a 4 ft extension to the ground floor of my house.
Its flat roof is leaking. It looks awkward to repair because the
extension has a parapet around it and the edge of the flat roof has
lead flashing all the way around, and because the outer edge, just
behind the parapet, is shaped into a trough to conduct the water along
to an outlet. Very fiddly indeed, I'd say. And the flashing is old and
I can already see a split in one place.

In order to avoid the repar, both now and in years to come, I'm
contempating having a sloping tiled roof put on, over the extension.
The dimensions (looking diectly downwards as in a plan drawing) ae
about, 5ft x 15ft. Does anyone have a clue what a builder would charge
to construct that? (So I can decide whether to DIM or just try to
repair the flat roof.)

Thanks,

John J