Flat Roofs on New Build Properties: What Buyers Should Know

Flat roofs are common on new build properties — particularly on extensions, garages, and modern architectural designs. Buying a property with a flat roof needn't be a concern if you know what to look for.

What System Should a New Build Have?

A new build flat roof should be either GRP fibreglass, EPDM rubber, or a quality single ply membrane. It should be installed as a warm roof with PIR insulation achieving the building regulations U-value. If the builder has used 3-layer mineral felt on a new build, that's a concern — demand a modern system.

Guarantees on New Build Roofs

New build homes covered by NHBC Buildmark warranty include the flat roof within the first 2-year developer warranty period and the 8-year structural warranty that follows. Ensure you receive copies of any specific roofing contractor guarantees as well.

What to Check Before Completion

At your snagging survey, check all flat roofs carefully. Look for: adequate falls (no visible puddles after rain), good detailing at all upstands and rooflights, clean and undamaged membrane surface, gutters properly fixed and fall-tested.

Ongoing Maintenance

A modern flat roof on a new build needs minimal maintenance in the first few years. Clear drains annually, clear any debris, and have a professional inspection every 5 years or before the NHBC warranty expires. Keep the builder informed of any issues within the warranty period.