Flat roof replacement across Buckinghamshire

Guide price

£3,100–£5,350

Survey

Free for new and replacement roofs

Quote

Fixed, in writing

Coverage

England, Wales, Scotland, NI

How much does a flat roof replacement cost in Buckinghamshire?

Guide prices including VAT at South East rates. The fixed price comes after a free survey for new and replacement roofs.

Which flat roofs are common in Buckinghamshire?

Flat roofs in Buckinghamshire sit on 1960s and 1970s link-detached houses with flat-roofed garages and porches, 1930s semis with flat-roofed garages and kitchen extensions and terraced streets with flat-roofed rear kitchens and bathrooms. Much of the South East sits in the drier Thames catchment at roughly 730 mm of rain a year, so the usual failures are at joints, upstands and outlets rather than from sheer volume of rain. 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 Buckinghamshire the application goes to Milton Keynes City Council and Buckinghamshire Council. 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 Buckinghamshire do we cover?

• Milton Keynes
• High Wycombe
• Aylesbury
• Bletchley
• Amersham
• Chesham
• Gerrards Cross
• Chalfont Saint Peter
• Marlow
• Newport Pagnell

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