Dormer windows in Basingstoke
Basingstoke homeowners come to us for dormer windows and dormer loft conversions that are properly detailed at the junctions — because that is where dormers succeed or fail.
What we build in Basingstoke
The housing stock around Basingstoke 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.
Whether that is a single flat roof dormer to make a back bedroom usable, or a full-width rear dormer with a bedroom and en-suite, the process is the same: a free measured survey first, a fixed written price second, and nothing else until you have both in front of you.
Planning permission in Basingstoke
If the property is in a conservation area or the dormer faces the road, a full planning application is needed. We prepare the drawings and handle the submission either way.
Basingstoke sits in Hampshire, and local authority interpretation of the volume allowance does vary — which is why we check the planning history at your specific address rather than assuming the neighbours' dormer sets a precedent.
How the job runs
Survey and feasibility
A specialist measures the roof, checks ridge height, span and structure, and confirms whether you are inside permitted development.
Scaffold and protection
Scaffold designed, erected and inspected. Temporary weather protection over the work area before anything is opened.
Weatherproofing
Deck, insulation, membrane or lead, cheek cladding, flashings and gutters — the dormer is weathertight from this point.
Finish and sign-off
Plaster, electrics, decoration and making good, final building control inspection and your completion certificate.
We would rather tell you at survey that your ridge height will not take what you want than take a deposit and find out in week three. The quickest route is a photograph of the rear elevation over WhatsApp — we can usually tell you what is feasible before anyone visits.
Popular in Basingstoke
Dormer work we are asked for most
Pitched Roof Dormers
A miniature pitched roof over the dormer — the traditional, period-correct option.
Learn moreFull-Width Rear Dormers
Wall-to-wall across the back of the roof — the biggest gain in usable floor area.
Learn moreCat Slide Dormers
The main roof continues down past the dormer — a soft, cottage-style profile.
Learn moreDormer Window Installation
Supply and fit of the window itself into new or existing dormer openings.
Learn moreAluminium Dormer Windows
Thermally broken aluminium — the slimmest frames and the largest possible glass area.
Learn moreGRP Fibreglass Dormer Roofing
Seamless glass-reinforced polyester on flat dormer tops — no joints, no seams.
Learn moreFAQs
Dormers in Basingstoke — FAQs
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.
Can you build a dormer on a bungalow?
Usually yes, and bungalows often give the best results because the spans are wide and there are no party walls. The deciding factor is ridge height: you generally want at least 2.6m from the top of the ceiling joists to the underside of the ridge. We measure this at survey before committing to anything.
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.
What insulation do dormers need?
Current building regulations want around 0.15–0.18 W/m²K for a new dormer roof and 0.18 W/m²K for the cheeks and front. In practice that is a warm-roof build-up using 100–150mm of PIR insulation above or between the structure, with a continuous vapour control layer on the warm side. Getting the VCL continuous matters more than the insulation thickness.
Do you handle the planning application?
Yes. We prepare measured drawings, elevations and sections, submit the application or the lawful development certificate, and deal with the case officer's queries. On conservation and listed work we also put together the heritage justification the application needs.
Find out what your roof will take
A free measured survey in Basingstoke tells you what is achievable, what it needs, and what it costs — before you commit to anything.