- Guide price
- £2,650–£4,650
- Survey
- Free for new and replacement roofs
- Quote
- Fixed, in writing
- Coverage
- England, Wales, Scotland, NI
Lancashire at a glance
- Largest towns
- Preston, Burnley, Blackburn, Blackpool
- Postcode areas
- BB, FY, L, LA, OL, PR, WN
- Building control
- Preston City Council, Burnley Borough Council, Blackburn with Darwen Borough Council and 10 other councils
- Neighbouring areas
- Greater Manchester · Merseyside · Cheshire · West Yorkshire
- Guide price region
- North West (−5% on West Midlands rates)
How much does a flat roof replacement cost in Lancashire?
Guide prices including VAT at North West rates. 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 | £2,650–£4,650 |
| Single garage (18 m²), torch-on felt | £1,450–£2,500 |
| Extension (20 m²), GRP, new deck + insulation | £2,850–£5,100 |
| Single garage (18 m²), EPDM rubber | £1,500–£2,650 |
Which flat roofs are common in Lancashire?
Flat roofs in Lancashire sit on 1960s and 1970s link-detached houses with flat-roofed garages and porches, bungalows with flat-roofed side extensions and dormers and low-rise post-war blocks of flats. The North West is one of England's wetter regions, averaging roughly 1,290 mm of rain a year, so falls, outlets and well-detailed upstands matter more than the membrane colour. Approximate 1991–2020 regional averages based on Met Office data.
Building regulations in England
Replacing more than half of a roof over a heated room usually counts as renovating a thermal element, so it is insulated to current standards and notified to building control. Renovated roofs over heated rooms are insulated to around 0.16 W/m²K where that's feasible, and new extension roofs are built to 0.15 W/m²K. In Lancashire the application goes to Preston City Council, Burnley Borough Council, Blackburn with Darwen Borough Council and 10 other councils. More on the rules.
Should I overlay my old flat roof or strip it fully?
Strip it fully if the deck is soft, the insulation is wet or the falls are wrong; an overlay only suits a dry, sound roof that already drains well. Covering a wet roof traps the moisture, and rot carries on out of sight.
An overlay also raises the roof level, eating into upstand height at walls and door thresholds, and every layer adds weight. In England, a covering that adds 15% or more to the roof's weight needs building control approval. Signs it is time to replace rather than repair:
- ponding that lingers long after rain
- blisters, cracking or crazing across wide areas
- bare bitumen where the mineral chippings have gone
- split laps and lifted upstands or flashings
- damp ceilings, or a deck that has gone soft
- leaks that return after each repair
A single defect on an otherwise dry roof can usually be put right with a repair. If you're unsure, a survey settles it, and our guides to overlay or strip and repair or replace go further.
Which system should I replace my flat roof with?
The right system depends on the roof's size, shape, use and number of details, so no single material suits every roof. These are the usual starting points:
- EPDM rubber suits simple, rectangular roofs, where one sheet can often cover the area with few or no joins.
- GRP fibreglass suits roofs with many corners, rooflights or edges, and gives a rigid surface for occasional maintenance traffic.
- Torch-on felt is a layered, hard-wearing system that keeps the cost down on larger or plain roofs.
- Liquid-applied systems handle awkward details and can overlay a sound existing surface.
- Single-ply and mastic asphalt are more usual on commercial roofs, blocks and terraces.
We recommend a system at survey and explain why. Our EPDM vs GRP vs felt guide sets out the trade-offs if you want to compare first.
Which towns in Lancashire do we cover?
- Preston
- Burnley
- Blackburn
- Blackpool
- Morecambe
- Lancaster
- Lytham St Annes
- Skelmersdale
- Leyland
- Accrington
- Chorley
- Darwen
- Thornton-Cleveleys
- Nelson
- Fleetwood
- Ormskirk
- Rawtenstall
- Colne
- Poulton-le-Fylde
- Heysham
- Haslingden
Flat roof replacement in Lancashire: questions
Which towns in Lancashire do you cover?
All of Lancashire. The main towns have their own pages below, and if yours isn't listed we still cover it: send your postcode and we'll confirm.
How much does a flat roof replacement cost in Lancashire?
£2,650–£4,650 for a 20 m² extension roof in EPDM with a new deck and insulation, at North West guide rates including VAT. The fixed price comes after a free survey for new and replacement roofs.
Which council handles building control for a flat roof in Lancashire?
It depends on where the roof is: in Lancashire that's Preston City Council, Burnley Borough Council, Blackburn with Darwen Borough Council and 10 other councils. Replacing more than half of a roof over a heated room usually counts as renovating a thermal element, so it is insulated to current standards and notified to building control. We confirm which applies at the survey.
Will a new flat roof be better insulated than the old one?
If it is over a heated room, yes. A full replacement usually has to be upgraded towards current insulation levels where feasible, and we build it as a warm roof with the insulation above the deck.
What time of year is best for a flat roof replacement?
Late spring to early autumn gives the most reliable dry spells, but a roof can be replaced in any season when the forecast allows. Adhesives and resins have minimum application temperatures, so winter work is planned around mild, dry days.
Can you replace just part of a flat roof?
Sometimes, if the rest is sound and dry. Renovating more than half of a roof over a heated room usually brings the whole roof under the insulation rules, so a full replacement can make more sense.
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