Hounslow at a glance
- Postcode districts
- TW3, TW5, TW4, TW7, UB2, TW14, UB1, TW13 and 2 more
- Council area
- London Borough of Hounslow
- Building approval
- London Borough of Hounslow building control, or a registered building control approver
- Guide price region
- London (+20% on West Midlands rates)
Why choose a green roof in Hounslow?
In a place like Hounslow, many people look out over a flat extension or garage roof from upstairs. Grey felt or rubber isn't much of a view, and a sedum roof turns it into something green that changes colour through the seasons and flowers in summer.
In and around Hounslow, flat roofs are typically found 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 green roof cost in Hounslow?
At London guide rates, a 20 m² insulated extension roof finished as a sedum green roof comes to £5,300–£9,700 including VAT. The fixed price comes after a free survey for new and replacement roofs.
| Job | Guide price inc VAT |
|---|---|
| Extension (20 m²), EPDM with sedum green roof | £5,300–£9,700 |
| Extension (20 m²), EPDM, new deck + insulation | £3,350–£5,850 |
Can my flat roof take the weight of a green roof?
Not every roof can, which is why we check the structure before quoting. A sedum roof is light compared with an intensive garden, but its growing medium holds water, and a saturated build-up adds significant weight to the roof.
We look at the joist sizes, spans and spacing, the condition of the deck and what the roof sits on. On a recently built extension with generously sized joists, an extensive green roof may be straightforward. On an older garage or a roof with undersized or rotten timbers, the structure may need strengthening, or a structural engineer's calculation may be needed before we can go ahead.
In England, a new roof covering that adds 15% or more to the weight of the roof triggers building control approval, and a green roof will often fall into that category. We handle building control where it is needed. The building regulations page covers the approval routes in each nation.
What's included?
- Warm or inverted build-up to suit the roof
- Gravel strips kept clear around edges and outlets
- Structural check of joists, deck and supports
- Pre-grown sedum blankets laid and watered in
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?
- Richmond upon Thames · 3 mi
- Ealing · 4 mi
- Kingston upon Thames · 5 mi
- Hammersmith and Fulham · 6 mi
- Hillingdon · 7 mi
- Brent · 7 mi
Green and sedum roofs in Hounslow: questions
Do you cover Hounslow?
Yes. Hounslow is part of our London coverage, including postcode districts TW3, TW5, TW4, TW7, UB2, TW14 and 4 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 Hounslow?
Where the work needs approval it goes to London Borough of Hounslow 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 green roof cost in Hounslow?
£5,300–£9,700 for a 20 m² insulated extension roof finished as a sedum green roof, at London guide rates including VAT. The fixed price comes after a free survey for new and replacement roofs.
Does a green roof leak more than a normal flat roof?
No, as long as it is built correctly. The waterproofing beneath is what keeps water out, and the green layers protect it from sun and weather. The main risk is building it on a weak or ageing membrane.
Can you put a green roof on a pitched roof?
We install green roofs on flat roofs only. Sloping green roofs need extra restraint to stop the growing medium slipping, and they are a specialist job outside our work.