Dormer windows in Cornwall
We design, build and weatherproof dormer windows and dormer loft conversions for homeowners across Cornwall, working from first survey through to building control sign-off.
Dormers on Cornwall roofs
Roofs across Cornwall are dominated by granite and rendered cottages, Victorian villas and post-war bungalows, and that mix decides almost everything about what a dormer here needs to look like and how it has to be built.
We survey the roof before quoting anything. Ridge height, rafter span, purlin position and the condition of the existing structure decide which dormer forms are possible — and there is no substitute for a tape measure in the loft. The survey is free and carries no obligation.
Planning permission in Cornwall
Rear dormers on houses often sit inside permitted development, but the volume allowance is consumed by any previous loft or rear extension — so we check the planning history for the address before we say yes.
What we do across Cornwall
One quotation covers scaffold, structure, weatherproofing, glazing, plastering and sign-off. You are not coordinating four trades who each blame the last one.
- New dormers — flat roof, pitched, gable-fronted, hipped, shed, box, L-shaped, eyebrow and cat slide forms
- Full conversions — structure, staircase, insulation, plaster and building control sign-off
- Glazing — uPVC, timber, aluminium, sash and heritage-profile conservation windows
- Cladding and roofing — tile-hung, slate-hung, lead, standing-seam zinc, cedar and GRP
- Repairs — leak tracing, flashing renewal, rot repair and blown unit replacement
Book the survey, get the fixed written price, and decide in your own time. Nothing about that process commits you to anything.
Services in Cornwall
Every dormer type, locally
Flat Roof Dormers in Cornwall
The most space-efficient dormer — a flat-topped box that squares off the roof slope.
Learn morePitched Roof Dormers in Cornwall
A miniature pitched roof over the dormer — the traditional, period-correct option.
Learn moreGable-Fronted Dormers in Cornwall
A pitched dormer with a vertical gable face — the classic 'dog-house' front elevation.
Learn moreHipped Roof Dormers in Cornwall
Three sloping faces instead of a gable — softer, and often easier to get past planning.
Learn moreShed Dormers in Cornwall
A single shallow slope running with the main roof — wide, low and understated.
Learn moreFull-Width Rear Dormers in Cornwall
Wall-to-wall across the back of the roof — the biggest gain in usable floor area.
Learn moreL-Shaped Dormers in Cornwall
A rear dormer joined to a second over the outrigger — the Victorian terrace answer.
Learn moreBox Dormers in Cornwall
A simple squared projection — the workhorse dormer for bedrooms and bathrooms.
Learn moreEyebrow Dormers in Cornwall
A curved, brow-like swell in the roof — no cheeks, no vertical faces.
Learn moreCat Slide Dormers in Cornwall
The main roof continues down past the dormer — a soft, cottage-style profile.
Learn moreDormer Loft Conversions in Cornwall
The full job — structure, dormer, stairs, insulation, plaster and building control sign-off.
Learn moreBungalow Dormer Conversions in Cornwall
Turn a bungalow's roof void into a first floor — often doubling the footprint.
Learn moreVelux to Dormer Conversions in Cornwall
Already have rooflights? Convert the slope to a dormer and gain standing height.
Learn moreDormer Window Installation in Cornwall
Supply and fit of the window itself into new or existing dormer openings.
Learn moreDormer Window Replacement in Cornwall
Swap tired, draughty or rotten dormer windows without touching the structure.
Learn moreuPVC Dormer Windows in Cornwall
Low maintenance, well insulated and the most cost-effective frame for a dormer.
Learn moreTimber Dormer Windows in Cornwall
Engineered hardwood or softwood — the right answer on period and listed roofs.
Learn moreAluminium Dormer Windows in Cornwall
Thermally broken aluminium — the slimmest frames and the largest possible glass area.
Learn moreSash Dormer Windows in Cornwall
Vertical sliding sashes sized and detailed for a dormer opening.
Learn moreConservation Dormer Windows in Cornwall
Heritage-profile dormers and glazing for conservation areas and listed buildings.
Learn moreDormer Cladding in Cornwall
Re-clad tired dormer cheeks and faces in tile, lead, zinc, timber or GRP.
Learn moreGRP Fibreglass Dormer Roofing in Cornwall
Seamless glass-reinforced polyester on flat dormer tops — no joints, no seams.
Learn moreLead & Zinc Dormer Roofing in Cornwall
Traditional code lead and standing-seam zinc for dormer roofs, cheeks and flashings.
Learn moreDormer Window Repairs in Cornwall
Leaks, rot, failed flashings, blown units and draughts — diagnosed and put right.
Learn moreWhat homeowners say
Judged on the junctions, not the sales pitch
“The survey was the useful bit — he told us the ridge height wouldn't take what we'd been sold elsewhere, and offered a shed dormer instead. Glad we listened.”
— Homeowner, Cornwall“Scaffold went up on the Monday, roof was open and weathertight by the Thursday. No drama, no surprises on the invoice.”
— Homeowner, Cornwall“We'd had two leaks patched by other firms. They traced it to the back gutter in an hour and it hasn't come back since.”
— Homeowner, CornwallComments shown are representative of feedback received. Verified reviews are being collected from launch.
FAQs
Dormers in Cornwall — FAQs
How disruptive is a dormer build?
Less than people expect, because most of the work happens above your ceilings and is reached from the scaffold. The noisy phases are opening up and installing steels, typically two to four days. Once the staircase is cut in there is dust and traffic through the house, and we sheet and protect the route for that period.
Can a dormer include an en-suite?
Very often, yes — a full-width or L-shaped dormer usually has enough floor area for a bedroom plus a shower room. The practical constraints are getting soil and waste down to an existing stack, and whether the head height over the shower tray works. Both are settled at survey.
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.
Do I need planning permission for a dormer window?
Rear dormers on a house often fall under permitted development, provided the dormer is set at least 200mm back from the eaves, sits below the ridge line, uses materials similar in appearance to the existing house, and stays within the volume allowance — 40m³ for a terrace, 50m³ for a semi or detached. Front-facing dormers, flats and maisonettes, listed buildings, conservation areas and any property with an Article 4 direction all need a full planning application. We check the constraints on your specific address before we quote.
How long does a dormer take to build?
A single box or flat roof dormer is typically three to five weeks on site. A full-width rear dormer runs five to eight weeks, and an L-shaped dormer on a terrace with an outrigger is closer to seven to ten. A complete dormer loft conversion including the staircase, services and finishes is usually eight to twelve weeks from scaffold up to sign-off.
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 Cornwall tells you what is achievable, what it needs, and what it costs — before you commit to anything.