Dormer windows in Dorset
From the first measured survey to the completion certificate, we run dormer windows and dormer loft conversions projects in Dorset as a single, managed piece of work.
Dormers on Dorset roofs
Roofs across Dorset are dominated by Victorian and Edwardian terraces, interwar semi-detached houses 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 Dorset
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 Dorset
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
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.
Towns and cities
Where we work in Dorset
10 towns and cities across Dorset, plus the surrounding villages.
Services in Dorset
Every dormer type, locally
Flat Roof Dormers in Dorset
The most space-efficient dormer — a flat-topped box that squares off the roof slope.
Learn morePitched Roof Dormers in Dorset
A miniature pitched roof over the dormer — the traditional, period-correct option.
Learn moreGable-Fronted Dormers in Dorset
A pitched dormer with a vertical gable face — the classic 'dog-house' front elevation.
Learn moreHipped Roof Dormers in Dorset
Three sloping faces instead of a gable — softer, and often easier to get past planning.
Learn moreShed Dormers in Dorset
A single shallow slope running with the main roof — wide, low and understated.
Learn moreFull-Width Rear Dormers in Dorset
Wall-to-wall across the back of the roof — the biggest gain in usable floor area.
Learn moreL-Shaped Dormers in Dorset
A rear dormer joined to a second over the outrigger — the Victorian terrace answer.
Learn moreBox Dormers in Dorset
A simple squared projection — the workhorse dormer for bedrooms and bathrooms.
Learn moreEyebrow Dormers in Dorset
A curved, brow-like swell in the roof — no cheeks, no vertical faces.
Learn moreCat Slide Dormers in Dorset
The main roof continues down past the dormer — a soft, cottage-style profile.
Learn moreDormer Loft Conversions in Dorset
The full job — structure, dormer, stairs, insulation, plaster and building control sign-off.
Learn moreBungalow Dormer Conversions in Dorset
Turn a bungalow's roof void into a first floor — often doubling the footprint.
Learn moreVelux to Dormer Conversions in Dorset
Already have rooflights? Convert the slope to a dormer and gain standing height.
Learn moreDormer Window Installation in Dorset
Supply and fit of the window itself into new or existing dormer openings.
Learn moreDormer Window Replacement in Dorset
Swap tired, draughty or rotten dormer windows without touching the structure.
Learn moreuPVC Dormer Windows in Dorset
Low maintenance, well insulated and the most cost-effective frame for a dormer.
Learn moreTimber Dormer Windows in Dorset
Engineered hardwood or softwood — the right answer on period and listed roofs.
Learn moreAluminium Dormer Windows in Dorset
Thermally broken aluminium — the slimmest frames and the largest possible glass area.
Learn moreSash Dormer Windows in Dorset
Vertical sliding sashes sized and detailed for a dormer opening.
Learn moreConservation Dormer Windows in Dorset
Heritage-profile dormers and glazing for conservation areas and listed buildings.
Learn moreDormer Cladding in Dorset
Re-clad tired dormer cheeks and faces in tile, lead, zinc, timber or GRP.
Learn moreGRP Fibreglass Dormer Roofing in Dorset
Seamless glass-reinforced polyester on flat dormer tops — no joints, no seams.
Learn moreLead & Zinc Dormer Roofing in Dorset
Traditional code lead and standing-seam zinc for dormer roofs, cheeks and flashings.
Learn moreDormer Window Repairs in Dorset
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, Dorset“Scaffold went up on the Monday, roof was open and weathertight by the Thursday. No drama, no surprises on the invoice.”
— Homeowner, Dorset“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, DorsetComments shown are representative of feedback received. Verified reviews are being collected from launch.
FAQs
Dormers in Dorset — FAQs
Do you work on listed buildings and in conservation areas?
Yes. That work is detail-led: matching sightlines, glazing bar widths, cill projections and cheek finishes to what survives, and specifying timber, lead and natural slate rather than modern equivalents. We prepare the drawings and heritage statement for listed building consent alongside the planning application.
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.
Do dormer windows need to be fire escape windows?
In a loft conversion, at least one window in each habitable room generally needs to meet escape requirements — a clear opening of at least 0.33m², minimum 450mm in both height and width, with the bottom of the opening between 800mm and 1100mm above floor level. We specify the opening lights to meet this as standard.
What happens to my existing loft insulation?
It comes out. Insulation at ceiling-joist level is in the wrong place once the loft is a room — the thermal line moves up to the new roof and dormer build-up. We remove and dispose of the old quilt and insulate the new envelope, which is also what makes the room comfortable to use in August.
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.
Will my roof be open to the weather?
No. The roof is only opened once the scaffold, temporary weather protection and materials are all on site, and the dormer is made weathertight — structure, deck, membrane and temporary glazing — before the crew leaves at the end of the opening-up phase. We do not open a roof on a Friday afternoon.
Find out what your roof will take
A free measured survey in Dorset tells you what is achievable, what it needs, and what it costs — before you commit to anything.