Flat roof repairs across Hertfordshire

Guide price

£160–£530

Repair price

Confirmed once the leak or damage is found

Condition survey report

£160–£320

Coverage

England, Wales, Scotland, NI

How much does a flat roof repair cost in Hertfordshire?

Guide prices including VAT at East of England rates. We confirm the price once we've traced the leak or seen the damage.

Which flat roofs are common in Hertfordshire?

Flat roofs in Hertfordshire sit on low-rise post-war blocks of flats, shops with flat-roofed rear stores below flats and terraced streets with flat-roofed rear kitchens and bathrooms. The East of England is the driest part of Britain, with parts of the Anglian region around 630 mm a year, so summer heat and UV, not rainfall, do most of the ageing on a felt roof. 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 Hertfordshire the application goes to Watford Borough Council, Dacorum Borough Council, Stevenage Borough Council and 7 other councils. More on the rules.

Should I repair or replace my flat roof?

Repair it if the defect is isolated and the rest of the roof is sound, dry and still well within its working life. Replace it if leaks keep coming back, cracking or blistering is widespread, the insulation is wet or the deck feels soft underfoot.

A useful test is to ask whether a repair would still look sensible if a second leak appeared somewhere else a few months later. On a roof near the end of its life, patching one split tends to move the problem rather than solve it, and repeated call-outs soon add up to a large share of the cost of a new roof. On a roof that is a few years old with one storm-damaged lap, a repair is the right answer and we will say so.

Our repair or replace guide sets out the signs in more detail, and the lifespan guide gives typical service lives for each system.

Which repair materials work with my type of flat roof?

The repair has to use the same system as the roof, because many flat roof materials don't bond to each other and some damage each other.

• Torch-on felt: repaired with compatible bitumen membrane, cut back to sound felt and lapped well beyond the defect. Torching near timber, insulation or fascias needs care, and some details are better done with cold-applied methods.
• EPDM rubber: repaired with EPDM patches and the manufacturer's primer and seam tape. Bitumen products and many general-purpose sealants won't bond to EPDM and shouldn't be used on it.
• GRP fibreglass: the area is ground back, then new resin and glass matting are laid and finished with topcoat to match.
• Liquid-applied and single-ply: repaired with the same manufacturer's products wherever possible, as mixing systems can affect a material guarantee.
• Mastic asphalt: cracks and blisters are cut out and made good with new asphalt by an operative who works with it.

A tin of roof sealant or bitumen paint may stop a drip for a while, but on the wrong membrane it makes a proper repair harder later.

Which towns in Hertfordshire do we cover?

• Watford
• Hemel Hempstead
• Stevenage
• St Albans
• Welwyn Garden City
• Cheshunt
• Hatfield
• Bishop's Stortford
• Borehamwood
• Hitchin
• Hoddesdon
• Letchworth Garden City
• Harpenden
• Bushey
• Hertford
• Rickmansworth
• Potters Bar
• Berkhamsted
• Ware
• Royston

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