Lambeth at a glance
- Postcode districts
- SW9, SW2, SW4, SE24, SW8, SW12, SE21, SE27 and 1 more
- Council area
- London Borough of Lambeth
- Building approval
- London Borough of Lambeth building control, or a registered building control approver
- Guide price region
- London (+20% on West Midlands rates)
When should a flat roof in Lambeth be replaced?
Selling or letting a property in Lambeth can also prompt a replacement. A buyer's surveyor will usually flag a flat roof near the end of its life, and a recent replacement with written workmanship and material guarantees answers that question before it turns into a negotiation point.
In a town like Lambeth, flat roofs are commonly found on shops with flat-roofed stores below flats above or mansard and dormer loft conversions. The Thames basin is one of the drier parts of Britain at roughly 730 mm of rain a year, but summer heat is the bigger test here: dark membranes on south-facing roofs swing a long way in temperature.
How much does a flat roof replacement cost in Lambeth?
At London guide rates, a 20 m² extension roof in EPDM with a new deck and insulation comes to £3,350–£5,850 including VAT. The fixed price comes after a free survey for new and replacement roofs.
| Job | Guide price inc VAT |
|---|---|
| Extension (20 m²), EPDM, new deck + insulation | £3,350–£5,850 |
| Single garage (18 m²), torch-on felt | £1,800–£3,150 |
| Extension (20 m²), GRP, new deck + insulation | £3,600–£6,450 |
| Single garage (18 m²), EPDM rubber | £1,900–£3,350 |
Which system should I replace my flat roof with?
The right system depends on the roof's size, shape, use and number of details, so no single material suits every roof. These are the usual starting points:
- EPDM rubber suits simple, rectangular roofs, where one sheet can often cover the area with few or no joins.
- GRP fibreglass suits roofs with many corners, rooflights or edges, and gives a rigid surface for occasional maintenance traffic.
- Torch-on felt is a layered, hard-wearing system that keeps the cost down on larger or plain roofs.
- Liquid-applied systems handle awkward details and can overlay a sound existing surface.
- Single-ply and mastic asphalt are more usual on commercial roofs, blocks and terraces.
We recommend a system at survey and explain why. Our EPDM vs GRP vs felt guide sets out the trade-offs if you want to compare first.
What's included?
- New deck, firrings and warm-roof insulation where needed
- Fixed written quote listing the full build-up
- Strip-out of the old covering, with waste and skip
- New membrane, upstands, edge trims and outlets
Building regulations in England
Replacing more than half of a flat roof over a heated room usually counts as renovating a thermal element, so the roof is insulated to around 0.16 W/m²K where that's technically and economically feasible, and the work is notified to building control: the council or a registered building control approver, unless a registered competent person self-certifies it. A roof on a new extension is built to 0.15 W/m²K. Patch repairs, and most unheated detached garages, don't trigger the upgrade. Structural changes, or a new covering that adds 15% or more to the roof's weight, also need approval. More on the rules.
Which nearby areas do we also cover?
- Southwark · 2 mi
- Wandsworth · 4 mi
- Westminster · 4 mi
- Lewisham · 4 mi
- Kensington and Chelsea · 4 mi
- Camden · 5 mi
Flat roof replacement in Lambeth: questions
Do you cover Lambeth?
Yes. Lambeth is part of our London coverage, including postcode districts SW9, SW2, SW4, SE24, SW8, SW12 and 3 more. Surveys and roofs are carried out by vetted roofing teams working under S&K Property Investments and Improvement Ltd.
Who checks building regulations for a flat roof in Lambeth?
Where the work needs approval it goes to London Borough of Lambeth building control, or a registered building control approver. We tell you at the survey whether your job needs it and deal with the paperwork as part of the quote.
How much does a flat roof replacement cost in Lambeth?
£3,350–£5,850 for a 20 m² extension roof in EPDM with a new deck and insulation, at London guide rates including VAT. The fixed price comes after a free survey for new and replacement roofs.
Can you replace just part of a flat roof?
Sometimes, if the rest is sound and dry. Renovating more than half of a roof over a heated room usually brings the whole roof under the insulation rules, so a full replacement can make more sense.
Will a replacement make my roof higher?
Usually a little, if insulation is added above the deck. We check door thresholds, window sills, upstands and wall flashings at survey so the new level works.