Dormer windows in Borehamwood
If you are weighing up dormer windows and dormer loft conversions in Borehamwood, we survey the roof, tell you what is actually achievable, and price it properly before anyone commits.
What we build in Borehamwood
Roofs across Borehamwood 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.
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 Borehamwood
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.
Borehamwood sits in Hertfordshire, 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
Finish and sign-off
Plaster, electrics, decoration and making good, final building control inspection and your completion certificate.
Design and consent
Measured drawings, elevations and sections. We submit the planning application or lawful development certificate and the building regulations application.
Structure
Ridge beam and floor steels craned or manhandled in, new joists laid, the dormer frame built and sheathed.
Glazing
Windows fitted square, sealed and drained, with escape-compliant opening lights where required.
The completion certificate is part of the deliverable, not an afterthought. It is the document that makes the space count when you come to sell. 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 Borehamwood
Dormer work we are asked for most
Cat 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 morePitched 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 moreFAQs
Dormers in Borehamwood — FAQs
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.
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.
Can you convert an existing Velux loft to a dormer?
Yes, and it is usually a shorter job than starting from scratch because the floor, staircase and services already exist. We verify the existing floor structure and any previous building control approval first, then cut and form the dormer into the finished room. Expect the room to be out of use for three to five weeks.
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.
Find out what your roof will take
A free measured survey in Borehamwood tells you what is achievable, what it needs, and what it costs — before you commit to anything.