North Walsham Roofers installs flat roofs on extensions, garages and outbuildings in Aylsham, and this page gives you honest guidance on what flat roofing work typically costs and why prices vary.
Flat roofing prices vary considerably depending on the size of the roof, the system being installed, the condition of the existing deck and how accessible the roof is. Giving a single price is not useful to anyone. What is useful is understanding the factors that push a price up or down - so you can judge whether a quote you receive is reasonable.
As a general guide for North Norfolk, a straightforward flat roof replacement on a single garage (roughly 15-20 square metres) using EPDM rubber typically costs in the range of £1,200 to £2,000. A felt replacement on the same roof sits lower, often in the range of £800 to £1,400. These are indicative figures only - your actual price will depend on the specifics below.
EPDM rubber membrane costs more to supply than traditional mineral felt, and the installation method is more labour-intensive. The material itself is priced per square metre, and for a residential job the cost difference between felt and EPDM on a typical garage or small extension roof can be several hundred pounds.
However, EPDM has a significantly longer working life - typically twenty years or more when correctly installed, versus ten to fifteen years for a good felt system. Over a twenty-year period, a homeowner who chooses felt will often spend more in total once a mid-life replacement and any interim repairs are factored in. The higher upfront cost of EPDM frequently works out cheaper over time.
When comparing options, ask for a price for each system so you can make a straightforward comparison.
Both material and labour costs scale with area. Roofers price flat work on a cost-per-square-metre basis for the membrane, plus a fixed element for setup, access and edge details that applies regardless of the roof size. This means that very small roofs (under ten square metres, such as a bay window top or small lean-to) can seem expensive per square metre relative to larger jobs - the fixed costs are spread over fewer metres.
Measure your roof before speaking to contractors. Length multiplied by width gives you a close approximation. Include any upstands and the area they cover in your notes - flashings are costed separately but knowing the roof area helps both you and the roofer have a sensible conversation.
This is the factor that most often causes a flat roofing price to change between initial estimate and final cost. The deck is the structural base the membrane sits on, typically plywood or OSB board over timber joists. If the deck has been wet for an extended period - through a leaking roof or failed flashing - sections of it will be soft and structurally compromised.
Replacing deck boards adds cost in both materials and time. A full deck replacement on a garage roof adds roughly £300 to £700 to a job, depending on the extent of the damage and the board thickness specified. Partial replacements cost less but still add to the total.
A roofer who surveys the roof before quoting should give you a view on the likely deck condition. Some deterioration can be assessed from above before stripping; other areas only become apparent once the old felt is off. If the survey reveals significant soft spots, ask for a clear explanation of how the deck replacement cost is priced and whether it is included in the original quote or subject to addition.
Most flat roofs on extensions and garages are at low level and straightforward to access with a short ladder or step-up. Some properties present complications - a flat roof on a rear extension that is reached through a narrow side passage, a roof abutting a conservatory, or a higher roof requiring scaffolding rather than a ladder and roof boards.
Scaffolding, where it is needed, adds to the cost. A simple scaffold structure for a low-level flat roof might add £200 to £400. More complex access arrangements cost more. Ask any contractor to confirm whether the quoted price includes access equipment or whether scaffolding is an addition.
Current building regulations require a minimum standard of insulation on flat roofs that are over heated spaces. On an extension roof, upgrading or installing new insulation is not optional if the work constitutes a replacement rather than a repair - building regulations apply to the full specification of the roof, not just the membrane.
Insulation board (rigid PIR foam board) adds cost to a job. The thickness required depends on the U-value target, but 100mm or more of PIR is typical on a heated extension. For a garage or outbuilding with no habitable space beneath, insulation is less critical. Confirm with your roofer whether building regulations apply to your specific job and whether insulation is included in the price.
The lead or code-lead flashings at parapet walls, chimney abutments and internal corners are priced separately from the membrane area. Lead is bought by weight and dressed by hand on site - it is skilled work and takes time. Expect flashings to add several hundred pounds to a complex job. A roof with a straightforward drip edge to gutter at three sides and one abutment wall will cost less in flashings than a roof surrounded by parapet walls on all sides.
A single small split or a lifted lap on a relatively young roof may be repairable without full replacement. Repairs are considerably cheaper than replacement - a straightforward patch on an EPDM roof, for example, might cost £150 to £350 depending on access and extent. However, repair is only the right answer if the rest of the roof is sound and has sufficient life remaining.
If a felt roof is approaching the end of its life and showing widespread surface cracking, repeated small repairs will cost more over two or three years than a single replacement now. A honest roofer will tell you which route makes financial sense for your specific roof, not simply offer the cheaper option to win the work.
When asking for quotes, make sure each contractor specifies the same things:
A quote that does not address these points is incomplete, and a lower headline price may become a higher actual cost once additional items are added.
We carry out flat roofing work in Aylsham and the surrounding area. Our base is North Walsham and we cover nearby towns and villages including Wroxham, Stalham, Mundesley, Bacton and Walcott. Call us to confirm coverage for your postcode.
Call North Walsham Roofers to arrange a survey and a detailed quote for your flat roof in Aylsham. When you request a quote, ask for the roof, the deck and the drainage to be assessed, and for a price that reflects what the job actually involves rather than a figure that changes once work starts.
No obligation · We usually respond within 2 hours
Storm damage, active leak, damaged ridge - we aim to be on-site within 24 hours.
