We are currently adding an extension to our house (1910 victorian) and our draftsman has asked if we would prefer a sloping roof (which is what we originally asked for and matches in with the neighbour's extension) or go for a pitched roof. We are worried about the additional costs this might add if we have a pitched roof. We know internally we can then put a higher angled ceiling if it is a pitched roof but we are worried about budget blowouts. Is it a lot more expensive to add a pitched roof than a sloping flat roof? The extension is 60sqm to the house.