- Guide price
- £12,150–£20,050
- Survey
- Free for new and replacement roofs
- Quote
- Fixed, in writing
- Coverage
- England, Wales, Scotland, NI
Caerphilly at a glance
- Largest towns
- Caerphilly, Risca, Gelligaer, Blackwood
- Postcode areas
- CF, NP
- Building control
- Caerphilly County Borough Council
- Neighbouring areas
- Torfaen · Merthyr Tydfil · Blaenau Gwent · Newport
- Guide price region
- Wales (−8% on West Midlands rates)
How much does a commercial flat roof cost in Caerphilly?
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 Caerphilly?
Flat roofs in Caerphilly sit on 1930s semis with flat-roofed garages and kitchen extensions, newer estates where the first extension roofs are now being replaced 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 Caerphilly the application goes to Caerphilly County Borough Council. More on the rules.
How do you handle CDM, roof access and fragile surfaces?
Every job is planned under the Construction (Design and Management) Regulations 2015, or CDM (NI) 2016 in Northern Ireland, with a construction phase plan and a method statement for the roof.
As a commercial client you have duties under CDM too, including passing on information about the building, such as drawings, details of previous roof work and the asbestos register. Buildings put up before 2000 can contain asbestos, so we ask for the register or a refurbishment survey before pricing a strip-out. If asbestos is found, a licensed specialist surveys and removes it before we start.
Roofs and rooflights are treated as fragile until a competent person confirms otherwise. Edge protection goes up on every job, rooflights and fragile sheets are covered or fenced off, and we agree safe access before work starts: scaffold, a tower, a powered access platform or a fixed access point where one is suitable.
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 Caerphilly do we cover?
Commercial flat roofing in Caerphilly: questions
Which towns in Caerphilly do you cover?
All of Caerphilly. 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 Caerphilly?
£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 Caerphilly?
It depends on where the roof is: in Caerphilly that's Caerphilly County Borough 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.
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.
Can you re-roof while our premises stay open?
Usually, yes. We phase the work so each section is watertight before the team leaves site, keep entrances and fire exits clear, and agree working hours and deliveries with you first.
Who deals with building control on a commercial re-roof?
We do, where the work needs approval. Replacing more than half of a roof over heated space usually means upgrading the insulation towards the renovation U-value where feasible, which is 0.18 W/m²K for non-domestic buildings in England.
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