GRP Fibreglass Dormer Roofing in Cardiff
We are a dormer specialist, not a general builder who occasionally does roofs — and across Cardiff that focus shows up in the detailing.
GRP Fibreglass Dormer Roofing — indicative geometry
GRP Fibreglass Dormer Roofing for Cardiff homes
Cardiff is a mix of Victorian and Edwardian terraces, interwar semi-detached houses and post-war bungalows, and each of those wants a different dormer form — which is why we survey before quoting rather than pricing off a photograph.
GRP is laid wet onto an 18mm OSB or ply deck and cures into one continuous laminate with the trims bonded in — there is no seam, no lap and no weld to fail. On a small flat dormer top with several upstands and a wall abutment, that seamlessness is worth a great deal. It needs dry weather and a temperature above about 5°C to lay properly.
Key specification
| Build-up | 18mm deck, CSM matting, polyester resin, topcoat |
|---|---|
| Trims | GRP edge, drip and wall trims bonded in |
| Design life | 20–25 years |
| Fall | 1:80 minimum |
Planning and building control in Cardiff
We run the permitted development test on your specific property: set-back from the eaves, height against the ridge, volume allowance and whether an Article 4 direction applies locally.
Building regulations approval is separate and always required. We submit the application, book the inspections around the programme and hand you the completion certificate at the end — the document a buyer's surveyor will ask to see.
Why homeowners in Cardiff use us
We only do dormers. That sounds like a limitation until you have watched a general builder improvise a back gutter on a wet Thursday.
Send us the address and roughly what you are hoping to gain, and we will come back with a realistic answer rather than an optimistic one.
Other dormer work in Cardiff
FAQs
GRP Fibreglass Dormer Roofing in Cardiff — FAQs
Does a dormer need building regulations approval?
Yes, always — permitted development covers planning, not building control. A dormer needs approval for structure, thermal performance under Part L, fire escape and protected route under Part B, and stairs under Part K if a staircase is involved. We handle the application, the inspections and the completion certificate.
Why is my dormer leaking?
In our experience the window itself is the cause less than a fifth of the time. Far more often it is the apron flashing at the dormer front, the lead soakers where the cheeks meet the roof slope, the back gutter behind a pitched dormer, or a split at an upstand in the flat covering. Water then tracks along a rafter and appears somewhere else entirely, which is why we trace the path before quoting.
Will a dormer add value to my house?
A properly built and signed-off dormer conversion adding a bedroom and bathroom typically returns a meaningful share of its cost in value, and more in areas where floor space is scarce. The building control completion certificate is what makes the space count as habitable floor area on a valuation — without it, surveyors will not include it.
Is scaffolding included in the price?
Yes. Every quotation we issue includes scaffold design, erection, weekly inspection, hire for the programme and dismantling. Scaffold appearing as an extra afterwards is one of the more common complaints about dormer work, so we price it in from the start.
How wide can a dormer be?
Structurally, as wide as the roof — full-width rear dormers regularly run six to eight metres, carried on a steel ridge beam. The limits are usually planning volume allowances and the setbacks needed at eaves and ridge, rather than what can be built.
Find out what your roof will take
A free measured survey in Cardiff tells you what is achievable, what it needs, and what it costs — before you commit to anything.