Hammersmith and Fulham at a glance
- Postcode districts
- W6, W14, W12, SW6, SW13, W4, SW14
- Council area
- London Borough of Hammersmith and Fulham
- Building approval
- London Borough of Hammersmith and Fulham building control, or a registered building control approver
- Guide price region
- London (+20% on West Midlands rates)
Why upgrade to a warm roof in Hammersmith and Fulham?
Landlords with flats and HMOs in Hammersmith and Fulham sometimes hear from tenants about cold top-floor rooms and black mould on ceilings. A warm roof upgrade during re-roofing tackles both the heat loss and the condensation behind the mould, and helps keep the roof timbers dry.
Around Hammersmith and Fulham, flat roofs are common on shops with flat-roofed stores below flats above and on 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 warm roof upgrade cost in Hammersmith and Fulham?
For Hammersmith and Fulham we use London rates: £3,350–£5,850 is the guide for a 20 m² extension roof in EPDM with a new deck and insulation, VAT included. 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 |
| Extension (20 m²), EPDM with sedum green roof | £5,300–£9,700 |
Will insulating the roof raise its height, and what about doors and upstands?
Yes. A warm roof makes the roof thicker, often by more than 100 mm depending on the insulation and the U-value target. That extra height is the main thing we plan around.
Waterproofing at a wall usually needs to rise about 150 mm above the finished roof surface, so if the roof gets higher, the upstand has to go higher too. That can be a problem where the roof meets a door threshold, a low window sill, a cavity tray or a rooflight kerb. At the edges, trims and fascias are reset to the new level, and gutters may need to move.
Where there isn't enough height, the options include using thinner, higher-performance insulation, lowering the deck where the structure allows, raising the sill or threshold, or, where it is genuinely not feasible to reach the full target, insulating as far as is reasonable and recording why with building control. We work this out at the survey so there are no surprises on the day.
What's included?
- Building control or building standards handled where needed
- Rigid insulation boards sized to the U-value target
- Survey of the deck, joists and existing insulation
- New waterproofing, with a written workmanship guarantee
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?
- Kensington and Chelsea · 1 mi
- Wandsworth · 3 mi
- Westminster · 3 mi
- Ealing · 4 mi
- Camden · 4 mi
- Lambeth · 5 mi
Warm roof insulation upgrades in Hammersmith and Fulham: questions
Do you cover Hammersmith and Fulham?
Yes. Hammersmith and Fulham is part of our London coverage, including postcode districts W6, W14, W12, SW6, SW13, W4 and 1 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 Hammersmith and Fulham?
Where the work needs approval it goes to London Borough of Hammersmith and Fulham 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 warm roof upgrade cost in Hammersmith and Fulham?
£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.
Is a warm roof worth it on a garage?
On a detached, unheated garage, usually not, as there is no heated space to protect and the thermal rules don't normally apply. On an integral or heated garage, or one being converted into a room, it is.
How thick does flat roof insulation need to be?
It depends on the insulation product and the U-value target. With common PIR boards, meeting a renovation target usually means well over 100 mm. Thinner, higher-performance boards are available where height is tight.