- Guide price
- £12,150–£20,050
- Survey
- Free for new and replacement roofs
- Quote
- Fixed, in writing
- 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 commercial flat roof cost in Cardiff?
Guide prices including VAT at Wales rates. The fixed price comes after a free survey for new and replacement roofs.
| Job | Guide price inc VAT |
|---|---|
| Commercial roof (100 m²), single-ply + insulation | £12,150–£20,050 |
| Condition survey and leak investigation | £140–£280 |
| Block of flats (150 m²), felt + insulation + scaffold | £14,300–£25,000 |
Which flat roofs are common in Cardiff?
Flat roofs in Cardiff sit on 1930s semis with flat-roofed garages and kitchen extensions, bungalows with flat-roofed side extensions and dormers and terraced streets with flat-roofed rear kitchens and bathrooms. 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.
Can you work around our trading hours and site rules?
Yes. Most commercial roofs can be replaced while the building stays open, and we agree the programme with you before any work starts.
That normally means set working hours, delivery and skip positions that keep entrances and fire exits clear, and phasing the roof so each section is watertight before the team leaves site. Noisy tasks such as strip-out can be timed for quieter periods, and early starts or weekend working can be arranged where your site allows. We tell you in advance which areas below the roof may be affected, so stock and equipment can be protected or moved.
Where torch-on felt is specified, the team works under your hot works permit system, with a fire watch after the torch is put away. If your site does not allow naked flames, we specify a cold-applied, self-adhesive or other flame-free system instead. Tenants, alarm companies and mechanical contractors are coordinated through one named contact.
Which roofing system suits a commercial flat roof?
Single-ply membrane usually suits large, simple roofs; built-up felt suits roofs with heavy foot traffic, plant or complex detailing; and a liquid-applied overlay suits a sound roof that needs new waterproofing without a full strip-out.
- Single-ply (PVC, TPO or FPO): light and quick to lay over large areas, with hot-air welded laps and fixing or bonding designed for the site's wind uplift. Indicative life 25–35+ years. See single-ply roofing.
- Built-up felt: two or three layers of reinforced bitumen membrane laid to BS 8217, hard-wearing around plant and maintenance routes. Modern systems last 15–25 years, high-performance systems longer. See torch-on felt roofing.
- Liquid-applied overlay: a reinforced coating that cures to one continuous layer, well suited to pipework, plant bases and awkward details. Indicative life 10–25+ years depending on the product. See liquid roofing.
Mastic asphalt suits concrete decks and walkways, and EPDM suits simpler roofs with few penetrations. An overlay only works where the existing roof is dry and firmly bonded, so we check for wet insulation before recommending one (see overlay or strip).
Which towns in Cardiff do we cover?
Commercial flat roofing 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 commercial flat roof cost in Cardiff?
£12,150–£20,050 for a 100 m² commercial roof in single-ply with insulation, at Wales guide rates including VAT. The fixed price comes after a free survey for new and replacement roofs.
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.
Can the cost be spread over more than one budget year?
Yes. We can price a phased programme with each section shown separately, starting with the most urgent areas, so you can plan the spend while the building stays protected.
Can our existing roof be overlaid instead of stripped?
Often, if the survey shows the existing covering is sound, dry and firmly bonded. Wet insulation, a soft deck or several old layers mean a strip-out is the better long-term answer.
Do you need a hot works permit?
Only if torch-on felt or other naked-flame work is used, in which case the team works under your permit system with a fire watch afterwards. Where hot works are not allowed, we specify a flame-free system such as a cold-applied membrane.
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