Flat roof replacement across Kent

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 Kent?

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 Kent?

Flat roofs in Kent sit on newer estates where the first extension roofs are now being replaced, lock-up garage blocks on estates and bungalows with flat-roofed side extensions and dormers. 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 Kent the application goes to Maidstone Borough Council, Medway Council, Tunbridge Wells Borough Council and 10 other councils. More on the rules.

Do I need building regulations approval to replace a flat roof?

Often, yes. Replacing the covering of a flat roof over a heated room is usually treated as renovating a thermal element, which brings insulation requirements and, in most cases, approval.

In England, if more than half of that roof is renovated, the whole roof should be upgraded towards a U-value of 0.16 W/m²K for homes (0.18 for non-domestic buildings) where that is technically, functionally and economically feasible, judged against a simple payback of 15 years. Approval comes from building control or self-certification through a registered competent person scheme. Structural changes, or a covering that adds 15% or more to the roof's weight, also need approval.

The other nations differ: most re-roofing in Wales needs approval, Scotland works through building standards and the building warrant, and in Northern Ireland you contact the district council's building control first. An unheated detached garage is not normally a thermal element. Planning permission is not usually needed if the roof looks much the same afterwards, though listed buildings and conservation areas are different. We handle approvals where needed; see building regulations.

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 Kent do we cover?

• Maidstone
• Gillingham
• Royal Tunbridge Wells
• Folkestone
• Margate
• Ashford
• Canterbury
• Sittingbourne
• Gravesend
• Dartford
• Ramsgate
• Dover
• Tonbridge
• Strood
• Whitstable
• Deal
• Sevenoaks
• Herne Bay
• Broadstairs
• Faversham
• Swanley
• Longfield
• Swanscombe

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