A flat roof replacement strips the old covering from a low-pitched roof and lays a new waterproof system, usually EPDM rubber, GRP fibreglass or torch-on felt, over a sound deck with correct falls, upstands, trims and outlets so rainwater drains away.
Addresses across SW13, SW14, W3 and W4 fall within our coverage for a new flat roof, so if your home is in Chiswick we can arrange a survey on a day that works for you. We inspect the existing building, discuss materials and layout, and then price the agreed specification in writing. Expect a guide range of £2,600–£5,800 including VAT before that visit.
- Guide price
- £2,600–£5,800 inc VAT
- Time on site
- 1–3 days for most roofs
- Postcodes
- SW13, SW14, W3, W4 and W6
- Planning rules
- England
- Local area
- Greater London
- Survey
- Free, with a written quote
What should you budget for a new flat roof in Chiswick?
No two jobs cost exactly the same, but the ranges below give a fair picture of a new flat roof in Chiswick. Pricing for London runs about 30% above the national guide, and the overall guide is £2,600–£5,800 with VAT included. We'll confirm your figure after surveying the property for free.
| Type of job | What it usually involves | Guide in Chiswick |
|---|---|---|
| Small roof (up to 8m²) | A dormer, bay, porch or small garage roof re-covered in EPDM or GRP. | £1,050–£2,600 |
| Extension or garage (15–25m²) | A typical extension or single garage roof stripped and re-covered. | £2,600–£5,800 |
| Large or new warm roof | Larger roofs, or roofs needing a new deck and insulation build-up. | £5,200–£11,500 |
The main things that change the figure:
- Roof area and access to the roof
- Condition of the deck and joists underneath
- Insulation upgrades and changes to roof height at edges
- Number of rooflights, pipes and upstands to detail
What do you get?
- Stripping and disposal of the old roof covering
- Replacement of rotten or soft deck boards
- New EPDM, GRP or torch-on felt membrane laid to falls
- Upstands, flashings and drip edges finished neatly
- New trims, outlets and gutter connections
- Rooflights refitted or replaced where required
Building in Chiswick
London's housing is dominated by Victorian and Edwardian terraces, often in yellow London stock brick, with Georgian terraces in central districts and mansion blocks across many inner areas. Outer boroughs have large belts of interwar semis, and there are extensive post-war council estates. Many houses have been split into flats, and conservation areas are widespread.
Terraces suit side-return extensions and rear dormer loft conversions; interwar semis commonly take hip-to-gable lofts. Shared party walls, restricted parking and conservation rules often shape the plans and the programme.
For a new flat roof in Chiswick, this means checking things like wall construction, roof structure and existing services before we put a figure on paper.
Planning and building rules in Chiswick
The notes below cover England, which is where Chiswick sits. Rules change and every property is different, so we speak to the council before pricing your job.
Re-roofing a house with similar materials does not usually need planning permission in England. Listed buildings and conservation areas may need consent if the covering changes.
Replacing more than a quarter of a roof’s covering counts as renovation under Building Regulations, so the work is notified and the roof insulation may need upgrading. Bats are protected across the UK; if they roost under roof tiles, soffits or fascias, work stops and a licensed ecologist advises before it restarts.
Rules change and every property is different, so we check the planning history and constraints for your address before we quote.
What happens after you get in touch?
A visit to your home
A free survey comes first. It gives us what we need to price a new flat roof properly, including dimensions, existing materials and access for deliveries, and gives you the chance to ask anything you like.
Price and scope agreed
We turn the survey notes into a written quote. The price is fixed for the specification we agree, and the document sets out materials, scope and payment stages in plain language.
Booking the work
With the quote agreed, we book the work in and handle preparation: permissions where needed, building control notifications, material orders and access arrangements for your Chiswick property.
Finish and handover
The job proceeds in the order set out in the programme, with dust and debris kept under control. Finally we tidy away, inspect the work together and pass the finished project over to you with its paperwork.
How we work
Common questions
How much does a new flat roof cost?
Re-covering a typical 15–25m² extension or garage roof costs £2,600–£5,800. As a guide, allow around £75–£170 per square metre plus fixed costs for stripping, waste and access, with torch-on felt at the lower end and GRP or EPDM with new decking or insulation at the top. Small dormer and porch roofs cost less overall but more per square metre. We confirm a fixed price after the survey.
How long does a flat roof replacement take?
Replacing a typical extension or garage flat roof usually takes one to three days. Stripping and any deck repairs come first, then insulation where agreed, the new membrane and the trims and outlets. GRP needs dry weather and time to cure, and we plan around the forecast. Larger roofs or roofs with many rooflights take longer. We confirm timing with your quote.
How long will a new flat roof take?
On a typical home, allow 1–3 days for most roofs. Larger projects, older buildings and extra work found once things are opened up can extend that, while simpler jobs may be shorter. Your quote includes an estimate of time on site, and your point of contact keeps you updated on the programme as the work progresses.
Is a flat roof suitable for a roof terrace?
A flat roof can only be used as a terrace if it is designed for it, with joists strong enough for people and furniture, a hard-wearing surface, safe edge protection and correct drainage. Using a standard extension roof as a terrace can damage it and may need planning permission and building regulations approval. We can advise on what a conversion would involve.
Can you combine a new flat roof with other work?
Yes. Because we manage several trades under one contract, we can plan a new flat roof alongside other work on your Chiswick home, such as new windows with rendering, or a kitchen refit with an extension. Combining jobs can reduce repeat set-up such as scaffolding, skips and access, and every element is listed and priced in the same written quote.
Also covering areas around Chiswick
Homes across SW13, SW14, W3 and W4 in Chiswick are within our coverage, as are those in Acton, Barnes and Shepherds Bush. If you are just outside these areas, ask anyway, because we work right across the UK.