Lewisham at a glance
- Postcode districts
- SE6, SE13, SE4, SE23, SE26, SE12, SE10, SE20
- Council area
- London Borough of Lewisham
- Building approval
- London Borough of Lewisham building control, or a registered building control approver
- Guide price region
- London (+20% on West Midlands rates)
Why choose torch-on felt roofing in Lewisham?
For a commercial roof in Lewisham, such as a shop, surgery or club, torch-on felt offers a hard-wearing mineral finish that takes occasional maintenance traffic. Phased work keeps part of the building weathertight while the rest is re-roofed, so the business can usually keep trading.
In a town like Lewisham, 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 torch-on felt roof cost in Lewisham?
Guide price in Lewisham: £1,800–£3,150 for a typical 18 m² garage roof in torch-on felt, including VAT at London rates. The fixed price comes after a free survey for new and replacement roofs.
| Job | Guide price inc VAT |
|---|---|
| Single garage (18 m²), torch-on felt | £1,800–£3,150 |
| Extension (20 m²), felt, new deck + insulation | £3,250–£5,600 |
| Block of flats (150 m²), felt + insulation + scaffold | £18,650–£32,650 |
| Single garage (18 m²), EPDM rubber | £1,900–£3,350 |
| Extension (20 m²), EPDM, new deck + insulation | £3,350–£5,850 |
Is torch-on roofing safe, and what is the difference between two- and three-layer systems?
Yes, torch-on is safe when hot works are properly controlled, because most roof fires linked to torching start at hidden timber or debris near edges and upstands, not on the open roof. Our teams follow a hot-works routine on every job:
- check eaves, fascias, soffits and wall cavities for timber, nests and debris before lighting a torch;
- use a cold-applied or self-adhesive membrane, rather than a flame, at edges, against combustible materials and in tight details;
- keep fire extinguishers on the roof and the gas bottles secured and away from the work;
- stop torching well before the team leaves, then carry out a fire watch so smouldering is spotted while people are still on site.
As for layers, a two-layer system (underlay plus cap sheet) is common on domestic roofs such as garages and extensions. A three-layer system adds an intermediate sheet, giving more thickness and redundancy, and is often specified on larger, commercial and multi-occupied roofs. The right choice depends on the size and use of the roof and the system's requirements, so we set it out in the quote.
Near a boundary, the external fire performance of the tested build-up, such as a BROOF(t4) classification, can also matter, and we check it where it applies.
What's included?
- Strip-off of the existing roof covering and removal of waste
- Two- or three-layer reinforced bitumen membrane with staggered laps
- Mineral-finished cap sheet, upstands, outlets and edge trims
- Hot-works checks and fire watch on every torch-on job
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?
Torch-on felt roofing in Lewisham: questions
Do you cover Lewisham?
Yes. Lewisham is part of our London coverage, including postcode districts SE6, SE13, SE4, SE23, SE26, SE12 and 2 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 Lewisham?
Where the work needs approval it goes to London Borough of Lewisham 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 torch-on felt roof cost in Lewisham?
£1,800–£3,150 for a typical 18 m² garage roof in torch-on felt, at London guide rates including VAT. The fixed price comes after a free survey for new and replacement roofs.
Is torch-on suitable for a block of flats?
Yes, layered bitumen systems are widely used on blocks of flats and commercial buildings. Larger roofs often use three layers and insulation, with hot works planned around residents.
Why does my felt roof have blisters?
Blisters usually form when moisture or air trapped beneath the felt expands in the sun. A few small, intact blisters may be monitored, but widespread or split blisters point to a repair or replacement.