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.
From a first conversation about a new flat roof to the day the site is cleared, homeowners in Barnet deal with us directly. We come out to measure up at no cost, explain the choices in plain terms and send a written quote. For context, comparable work in London usually falls within £2,600–£5,800 including VAT, and it is available across EN4, EN5, N3 and N12.
- Guide price
- £2,600–£5,800 inc VAT
- Time on site
- 1–3 days for most roofs
- Postcodes
- EN4, EN5, N3, N12 and N20
- Planning rules
- England
- Local area
- Greater London
- Survey
- Free, with a written quote
Flat roofs prices in Barnet
Prices for a new flat roof vary from house to house, but in Barnet most projects fall within £2,600–£5,800 including VAT. That reflects costs in London, about 30% above the national guide. Treat the table as a budgeting aid; the written figure follows a survey we carry out for free.
| Type of job | What it usually involves | Guide in Barnet |
|---|---|---|
| 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 |
Your price depends mostly on:
- Roof area and access to the roof
- Covering system: EPDM, GRP or torch-on felt
- Condition of the deck and joists underneath
- Insulation upgrades and changes to roof height at edges
What’s included?
- Survey of the covering, deck, falls, upstands and drainage
- Stripping and disposal of the old roof covering
- Replacement of rotten or soft deck boards
- Insulation upgrade to a warm roof build-up where agreed
- New trims, outlets and gutter connections
- Rooflights refitted or replaced where required
Local housing and a new flat roof
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.
That variety is why a guide price for a new flat roof in Barnet is only a starting point; the survey shows what your particular property needs.
Permissions for a new flat roof in Barnet
For anyone in Barnet, the relevant framework is England's. The summary below is general, so we always contact the council about your address before putting a price in writing.
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.
The four stages
We look at the job
We begin by looking at the job in person. During the free survey we discuss options, materials and budget for a new flat roof, and photograph or measure anything the quote needs to reflect.
Your fixed price
You get the price in writing, itemised so you can see where the money goes. As long as the specification stays the same, that is the price you pay for a new flat roof.
Plan and prepare
Once you accept, we agree start dates, order materials and deal with any planning, building control or neighbour notices the job needs. You'll know who is coming and when before work begins.
Build and hand over
Our trades complete a new flat roof while your point of contact keeps you updated. When everything is finished, we clear the site, take away waste and go through the result with you before handover.
What you can expect from us
Frequently asked questions
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.
Who do I deal with during the job?
One point of contact manages your project from survey to handover. They schedule the trades working under our contract, keep you updated on progress, and are the person to call with any question. You don't need to coordinate builders, electricians or decorators separately, because that is part of what we do.
Which is better, EPDM rubber or GRP fibreglass?
EPDM rubber and GRP fibreglass are both reliable modern flat roof systems. EPDM is a single flexible sheet with very few joints, which copes well with movement and suits most extensions and garages. GRP is a hard, seamless finish that copes better with foot traffic and complex shapes, but needs dry weather to apply. Felt costs less but usually lasts less long. We recommend a system after seeing your roof.
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.
Can I stay at home during the work?
In most cases, yes. Most people can live at home throughout, and we plan the work to keep disruption down by protecting floors, agreeing working hours and keeping access routes clear. Bigger jobs affecting kitchens, bathrooms or heating may mean a short spell with reduced facilities, and we talk this through with you at the survey.
Near Barnet
Homes across EN4, EN5, N3 and N12 in Barnet are within our coverage, as are those in East Barnet, Hadley Wood and Potters Bar. If you are just outside these areas, ask anyway, because we work right across the UK.