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Flat roofing: replacements, new decks and repairs
Extensions, garages, dormers, bays and porches. We strip failed flat roofs, build new timber decks where the old one has gone, and lay EPDM rubber or high-performance felt to proper falls so water runs off instead of sitting there.
What a flat roof replacement includes
A new flat roof is only as good as what it sits on, so the price covers the whole build-up and not just the top layer:
- Stripping the old covering and checking the deck underneath
- New timber joists or firrings where the falls are wrong, and new OSB or ply decking where the old boards are wet or soft
- The covering itself: an EPDM rubber membrane or a multi-layer torch-on felt system
- Upstands turned properly up walls and finished under lead or a trim
- New edge trims, drip details and outlets into the gutter
- Skips, making good and clearing away
EPDM or felt?
EPDM is a single sheet of synthetic rubber, usually with no joins at all on a house roof. It copes well with movement and cold, and it is our usual choice for extensions, dormers and bays. Torch-on felt is a modern two or three layer system with a mineral finish. It is tough, easy to repair and often the better answer on larger roofs with lots of details. We recommend one at the quote visit and tell you why.
- Small extension or garage, sound structure: EPDM or felt both work well
- Dormer or anything that moves a little: EPDM
- Large roof with lots of pipes, roof lights and awkward details: torch-on felt
- Balcony or roof that will be walked on: tell us, because it needs a different build-up
Why so many flat roofs fail early
Two reasons, and neither is the covering people blame. Falls: a flat roof needs a steady slope to an outlet, and water left standing finds a weakness in any material. Edges: most leaks start where the roof meets a wall, a door or a pipe, not in the middle. A new covering over bad falls and poor edges buys a few years. We correct both, which is why our quotes often include new firrings rather than just a new top layer.
Questions
How long should a new flat roof last?
Laid properly on correct falls, a modern EPDM or felt roof should last decades rather than years. Poor falls and edges shorten any of them.
Can you go over the existing roof?
Sometimes, and an overlay can be good value on a dry, sound roof. If the deck is wet or the falls are wrong, an overlay seals the problem in, and we will tell you so.
How long does it take?
Most extension and garage roofs are one to three days, depending on whether the deck needs rebuilding.