- Guide price
- £140–£460
- Repair price
- Confirmed once the leak or damage is found
- Condition survey report
- £140–£280
- Coverage
- England, Wales, Scotland, NI
Cardiff at a glance
- Largest towns
- Cardiff, Whitchurch
- Postcode areas
- CF
- Building control
- Cardiff Council
- Neighbouring areas
- Vale of Glamorgan · Caerphilly · Newport · Rhondda Cynon Taf
- Guide price region
- Wales (−8% on West Midlands rates)
How much does a flat roof repair cost in Cardiff?
Guide prices including VAT at Wales rates. We confirm the price once we've traced the leak or seen the damage.
| Job | Guide price inc VAT |
|---|---|
| Localised patch repair | £140–£460 |
| Upstand or flashing repair | £230–£600 |
| Outlet or drainage repair | £110–£320 |
| Emergency temporary weatherproofing visit | £170–£410 |
| Condition survey and leak investigation | £140–£280 |
Which flat roofs are common in Cardiff?
Flat roofs in Cardiff sit on lock-up garage blocks on estates, terraced streets with flat-roofed rear kitchens and bathrooms and 1930s semis with flat-roofed garages and kitchen extensions. Wales averages roughly 1,460 mm of rain a year, among the wettest in Britain, so we design for steady run-off: proper falls, clear outlets and upstands well above the finished roof. Approximate 1991–2020 regional averages based on Met Office data.
Building regulations in Wales
Welsh guidance is that most re-roofing needs building control approval, so it's worth checking whenever more than a quarter of a roof is replaced or repaired. Renovated roofs are upgraded to around 0.16 W/m²K where feasible, and new extension roofs are built to 0.13 W/m²K under the Welsh Approved Document L. In Cardiff the application goes to Cardiff Council. More on the rules.
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.
How long will a flat roof repair last?
A well-made repair on a roof that is otherwise sound should last as long as the covering around it. It can't add years to the rest of the roof, though.
If your felt roof is twenty years old, a perfect patch still leaves twenty-year-old felt around it, and the next weak point will appear in its own time. That is why we give you an honest view of how much life the roof has left, so you can decide whether a repair now and a planned replacement later is better value than replacing straight away.
Simple care helps any repair last. Clearing leaves from outlets and gutters, keeping people off roofs that aren't designed for foot traffic, and looking over upstands and edges after storms all catch small problems before they reach the ceiling. Our maintenance guide lists the checks worth doing each year.
Which towns in Cardiff do we cover?
Flat roof repairs in Cardiff: questions
Which towns in Cardiff do you cover?
All of Cardiff. The main towns have their own pages below, and if yours isn't listed we still cover it: send your postcode and we'll confirm.
How much does a flat roof repair cost in Cardiff?
£140–£460 for a localised patch repair, at Wales guide rates including VAT. We confirm the price once we've traced the leak or seen the damage.
Which council handles building control for a flat roof in Cardiff?
It depends on where the roof is: in Cardiff that's Cardiff Council. Welsh guidance is that most re-roofing needs building control approval, so it's worth checking whenever more than a quarter of a roof is replaced or repaired. We confirm which applies at the survey.
Will a repair affect my roof's guarantee?
It can. If the roof is still under a manufacturer's material guarantee, the repair should normally use that manufacturer's products and methods, so share any guarantee paperwork with us before work starts.
Can a GRP roof be repaired?
Yes. The damaged area is ground back, new resin and matting are laid over it and a matching topcoat goes on top. Cracks that keep reappearing along the same line often point to movement in the deck, which needs fixing first.
How long does a flat roof repair take?
Most small repairs take a few hours on site once the roof is dry. Larger upstand or outlet repairs can take a day or more, and setting up scaffold or access equipment adds time.
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