Box Dormers in Carmarthenshire
We are a dormer specialist, not a general builder who occasionally does roofs — and across Carmarthenshire that focus shows up in the detailing.
Box Dormers — indicative geometry
Box Dormers for Carmarthenshire homes
The housing stock around Carmarthenshire runs to Victorian and Edwardian terraces, interwar semi-detached houses and post-war bungalows — so the first question at survey is always which of those you have, because the structure underneath differs completely.
A box dormer is the plainest form there is: two cheeks, a flat or very shallow top, and a flat front. There is nothing clever about it, which is precisely the point — fewer junctions means fewer places to leak, and a shorter programme on site. Most single-room dormers on post-war housing are box dormers whether or not anyone calls them that.
Key specification
| Typical projection | 1.5m – 3.5m wide |
|---|---|
| Depth | 1.8m – 3.0m into the roof |
| Roof finish | GRP, EPDM or felt |
| Cheek finish | Tile-hung, GRP or vertical cladding |
Planning and building control in Carmarthenshire
Whether you need planning permission or a lawful development certificate depends on the elevation, the volume already used and the local authority's Article 4 position — all of which we confirm before design work starts.
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 Carmarthenshire use us
One quotation covers scaffold, structure, weatherproofing, glazing, plastering and sign-off. You are not coordinating four trades who each blame the last one.
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 Carmarthenshire
- Pitched Roof Dormers in Carmarthenshire
- Shed Dormers in Carmarthenshire
- Eyebrow Dormers in Carmarthenshire
- Bungalow Dormer Conversions in Carmarthenshire
- Dormer Window Replacement in Carmarthenshire
- Aluminium Dormer Windows in Carmarthenshire
- Dormer Cladding in Carmarthenshire
- Dormer Window Repairs in Carmarthenshire
FAQs
Box Dormers in Carmarthenshire — FAQs
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.
What guarantees do you provide?
Structural work carries a ten-year guarantee, GRP and EPDM flat roofing twenty years, windows ten years on frames and sealed units, and lead and zinc work is covered for workmanship for ten years. You also receive the building control completion certificate, which is the document that actually matters when you sell.
Can you build a dormer in winter?
Yes, with adjustments. Temporary weather protection over the scaffold lets structural work continue in most conditions. GRP roofing needs dry conditions above about 5°C to cure properly, so in a cold spell we either sequence it differently or specify EPDM, which is unaffected.
How much does a dormer window cost?
A single flat roof dormer typically runs from around £9,000 to £20,000 supplied and fitted, depending on width, cladding finish and access. A full-width rear dormer on a semi is usually £28,000 to £45,000, and a complete dormer loft conversion including stairs, insulation, plaster and building control sign-off is more commonly £40,000 to £70,000. Our online guide-price tool gives you an indicative range in about a minute.
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.
Find out what your roof will take
A free measured survey in Carmarthenshire tells you what is achievable, what it needs, and what it costs — before you commit to anything.