Flat Roof Replacement Cost in the UK

Two roofs of the same size can differ in cost by a wide margin. Access, the condition of the deck, insulation requirements, the number of upstands and outlets, and whether the existing covering can stay in place all change the figure.

For a ballpark based on your own roof, use our instant estimate tool: you plot the roof on a satellite map and we work out the area and access. A site visit then confirms the final, itemised price.

• Roof area and shape: measured, not guessed, from the satellite plot or site visit.
• Access and scaffolding: number of floors, roof access and edge protection needed.
• Deck condition: sound decks can be overlaid; rotten or saturated boards must be replaced.
• Insulation: upgrading to a warm roof to meet current Building Regulations adds materials and height.
• Detailing: upstands, parapets, outlets, rooflights and trims add labour time.
• Strip-out and waste: removing the old roof means skips, disposal and weather exposure.

Most failing flat roofs need new waterproofing, not a new structure. Our Ultraflex cold-liquid system bonds over existing felt, asphalt, GRP and many other surfaces, which removes strip-out, skip and much of the labour cost. It typically costs up to 50% less than a traditional replacement.

Where the deck or insulation has genuinely failed, we strip back and rebuild warm or cold roof build-ups to current regulations. A survey tells you which applies before you commit.

• Measured roof area and a description of the proposed build-up
• Access, scaffolding and edge protection
• Deck repairs or replacement allowances, clearly stated
• Detailing to upstands, outlets, trims and rooflights
• Waste removal and site clean-up
• Guarantee length and who backs it
• Exclusions, such as structural repairs, internal making good and parking permits