Flat Roof Dormers in Somerset
From the first measured survey to the completion certificate, we run flat roof dormers projects in Somerset as a single, managed piece of work.
Flat Roof Dormers — indicative geometry
Flat Roof Dormers for Somerset homes
Most of the dormer work we take on around Somerset is on Victorian and Edwardian terraces, interwar semi-detached houses and post-war bungalows, where the ridge height and the position of the existing purlins set the limits.
A flat roof dormer projects square from the roof slope with a shallow-fall flat top, usually finished in GRP fibreglass, EPDM or single-ply membrane. Because the walls are vertical and the ceiling is level, you keep full standing height right up to the window — which is why it is the default choice on rear elevations where planning is under permitted development.
Key specification
| Typical projection | 1.8m – 6.0m wide |
|---|---|
| Roof fall | 1:80 minimum to the rear |
| Roof finish | GRP, EPDM or single-ply membrane |
| Cheek finish | Tile-hung, GRP, lead, zinc or timber |
Planning and building control in Somerset
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.
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 Somerset use us
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.
Other dormer work in Somerset
FAQs
Flat Roof Dormers in Somerset — FAQs
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 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.
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.
Can I put a dormer on the front of my house?
Front-facing dormers are not covered by permitted development and always need a full planning application. Approval depends heavily on the street scene — planners look at whether other dormers already exist on the road, and at proportion, position and materials. Hipped and pitched forms are approved far more often than flat boxes on a front elevation.
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 Somerset tells you what is achievable, what it needs, and what it costs — before you commit to anything.