Domestic vs commercial roofing work
Most roofers who work on homes also cover garages, outbuildings and small extensions, but larger commercial flat-roof work (warehouses, larger extensions) sometimes needs a roofer with specific experience in bigger membrane systems. Worth asking directly if your job is unusually large or non-standard.
What affects the cost
Cost depends on roof size and pitch (steeper roofs need more scaffolding and take longer), the material (slate costs more than concrete tile), access, and whether the existing roof structure (timbers, felt) needs work too, not just the visible covering. A straightforward repair is quick; a full re-roof including scaffolding commonly takes 1-3 weeks.
Roofing felt vs breathable membrane
Older roofs often used bituminous felt underneath the tiles, which can perish and needs replacing during a re-roof; modern breathable membrane lasts longer and manages moisture better. If you're having a full re-roof, this underlay is worth confirming as part of the spec, not just the visible tiles.
Flat roof vs pitched roof considerations
Flat roofs (felt, GRP fibreglass, or rubber/EPDM) typically need replacing more often than a pitched tiled roof, but repairs are usually quicker and cheaper. A flat roof extension on an older pitched-roof property is common and often uses a different material and roofer specialism than the main roof.
Three steps to hiring the right roofer
First, check NFRC membership or equivalent trade body registration. Second, ask for photos of similar completed jobs, ideally local ones. Third, clarify what happens if underlying roof timbers turn out to need work once the old covering is removed — a very common mid-job discovery.
Dormer windows and roofline alterations
A dormer window (as opposed to a flush skylight) changes the roofline itself and almost always needs both planning consideration and Building Regulations sign-off, unlike a straightforward re-roof. This is more involved than most roofing work and often overlaps with loft conversion specialists.
Roof orientation and solar suitability
A south-facing roof slope generally gets the most useful sun for solar panels, though east/west-facing roofs can still work reasonably well. A roofer or solar installer assessing suitability will look at pitch, orientation, shading from nearby trees or buildings, and roof structural capacity together.
Common roofing myths, busted
"A few loose tiles are always urgent" — sometimes, but not always; a roofer can usually tell you if it can wait for a scheduled visit. "Moss means the roof needs replacing" — not necessarily, see roof cleaning above. "Flat roofs always leak eventually" — modern EPDM/rubber flat roofing lasts decades if properly installed.