Professional Flat Roofing Services
Flat and low-pitched roofs cover extensions, garages, dormer cheeks, bay windows and many London terraces and mansion blocks. With no steep pitch to shed water, every joint, upstand and outlet has to be right. A badly installed flat roof can fail within a few years; a well-built one should last for decades.
Putney & Wimbledon Roofers repairs, replaces and installs flat roofs across Putney, Wimbledon and South West London, using torch-on felt, warm roof build-ups and GRP fibreglass. Complete flat roof renewals carry our 10-year insurance-backed guarantee.
Recent flat roofing work has included the replacement of a UV-degraded felt roof in Wimbledon, where the deck was renewed and a three-layer torch-on felt system installed, and the conversion of an unsafe pitched roof into a warm flat roof. See the full case studies.
- Flat Roof Repairs
- Flat Roof Replacement
- New Flat Roof Installation
- Leak & Crack Solutions
- Water Pooling Assessment
- Edge & Junction Repairs
Common Flat Roof Problems & Assessment
Common flat roof problems include leaks, cracking and blistering from UV exposure, standing water from poor falls or blocked outlets, worn surfaces, and failure around edges, upstands and junctions.
If you notice a leak, cracking, ponding water or repeated problems, contact us and we will inspect the roof, explain the cause and tell you whether a repair will hold or the roof needs renewing.
Need Help With Your Flat Roof?
020 3633 9588
Flat roofing at a glance
- Systems: three-layer torch-on felt, warm flat roofs and GRP fibreglass
- Services: repairs, overlays, full replacement and new flat roofs for extensions and garages
- Standards: we follow BS 8217 for felt roofing where it applies
- Guarantee: 10-year insurance-backed guarantee on complete flat roof renewals
- Survey and quote: free, itemised and in writing
- Emergency leaks: available 24 hours
Flat roof systems we install
Three-layer torch-on felt
Our most common specification is a multi-layer bitumen system: a base layer, an intermediate layer and a mineral-finished cap sheet, heat-bonded to form one continuous waterproof surface. It is durable, repairable, well suited to the London climate and ideal for larger roofs.
Warm flat roofs
In a warm roof the insulation sits above the deck, so the structure stays warm and no cold void exists where condensation can form. A typical build-up is an 18mm OSB deck, a vapour control layer, rigid insulation boards such as Celotex, a second deck, and the waterproof covering. Because a warm roof needs no ventilation, it is the best answer to damp or mouldy ceilings caused by condensation.
GRP fibreglass
A seamless, jointless finish made from glass matting, resin and a UV-stable top coat. It suits small roofs, balconies and awkward shapes. The top coat is essential: we have been called in to redo fibreglass roofs where general builders left it out. We use quality Cure It matting, resin and top coat with code 4 lead flashing at abutments.
Repairs and patching
Where the deck is sound and damage is localised, we repair split joints, punctures, blisters and failed upstands rather than recommend a new roof. If the felt is degraded across the whole surface, we will tell you so.
Flat roof renewal: what is involved
- Survey. We check the deck, falls, outlets and any signs of trapped moisture or rot.
- Strip-out. The failed covering and any rotten boards are removed.
- New deck. 18mm OSB boards are laid and secured, with falls corrected so water drains rather than ponds.
- Insulation and vapour control. Fitted where a warm roof is specified.
- Waterproofing. Felt or GRP with proper upstands, drip edges and lead flashings at walls and chimneys.
- Handover. Photographs, a clean site and your written guarantee.
What affects the cost of a flat roof?
| Factor | Why it matters |
|---|---|
| Roof size | Material and labour scale with area; small roofs still carry set-up costs. |
| System chosen | Torch-on felt, GRP and warm-roof build-ups each have different material costs. |
| Condition of the deck | Rotten or wet boards must be replaced before waterproofing. |
| Insulation | A warm roof costs more upfront but removes condensation and improves thermal performance. |
| Drainage and falls | Correcting falls or adding outlets adds work but prevents ponding. |
| Access and edge detail | Parapets, lead flashings, roof lights and difficult access affect time and cost. |
Guide prices
| Job | What it covers | Guide price |
|---|---|---|
| Small flat roof | Porch, bay or dormer roof in three-layer torch-on felt | From £1,450 per roof |
| Garage or extension roof | New deck where needed and three-layer torch-on felt | From £2,950 per roof |
| Warm flat roof | Insulated build-up with vapour control layer and new deck | From £4,950 per roof |
| GRP fibreglass roof | Matting, resin and Cure It top coat, with lead flashings | From £2,450 per roof |
Prices are a guide for a typical South West London house and include labour and materials. Scaffolding and access are priced separately. Every roof is different, so after a free survey you receive a fixed, itemised written quote. Request a free quote.
Is your flat roof in need of repair?
- Leaks or water stains on ceilings below the roof.
- Pooling water that has not cleared within a couple of days, which points to poor falls or a blocked outlet.
- Cracking, blistering or splits in the surface, usually from age and UV.
- A sagging or spongy surface, which suggests the deck beneath has rotted.
- Moss, weeds or debris holding moisture on the roof.
- Condensation, damp or mould inside, often a sign of a cold-deck roof without proper insulation or ventilation.
A pitched roof turned into a warm flat roof
One of our most unusual jobs began as a leak. A customer’s artificial-slate pitched roof was letting water in because the slates were wrong for the pitch and there was no lead flashing. When we stripped it, we found the pitched roof had been built on top of an old flat roof, with rafters barely secured and no wall plate. We explained that it was unsafe and recommended removing it and building a warm flat roof, which also solved the condensation problem caused by two roofs sandwiched together. It was finished with an 18mm OSB deck, a vapour control layer, Celotex insulation boards, a second deck and a three-layer torch-on felt system. Read the full case study.
The true cost of cheap work
- Poor drainage. Without correct falls, water ponds and shortens the life of any covering.
- Thin or single-layer coverings. They fail quickly where a multi-layer system would last.
- Badly detailed edges and upstands. Where most flat roof leaks begin.
- No top coat on GRP. Left unprotected, the resin degrades in sunlight.
- No insulation or vapour control. Leads to condensation, mould and higher energy bills.
Looking after your roof also matters. Keep outlets and gutters clear, remove leaves and debris, avoid walking on the surface, and have it checked after severe weather. Our gutter repair and drone survey services help with routine checks.
Flat roofing across South West London
We work in Putney, Wimbledon, Wandsworth, Richmond, Kingston upon Thames, Twickenham, Balham, Tooting and surrounding areas. See areas we cover or request a free quote.
Flat roofs in the area range from small porch and dormer roofs to garage and extension roofs. We inspect the deck, falls, upstands and drainage before recommending felt, GRP fibreglass or a warm flat roof, and we give you a written quote with the specification set out. Complete flat roof renewals carry a 10-year guarantee.
Frequently Asked Questions: Flat Roofing
Clear, practical answers from our 3rd-generation roofing team in South West London.
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