L-Shaped Dormers in Greater London
Our teams install l-shaped dormers throughout Greater London, handling structure, weatherproofing, glazing and finish as one job with one point of contact.
L-Shaped Dormers — indicative geometry
L-Shaped Dormers for Greater London homes
Because Greater London is largely Victorian and Edwardian terraces with rear outriggers, plus large stretches of 1930s semi-detached suburbs, the roof pitches and span widths we meet are fairly predictable, and that makes feasibility a quick conversation rather than a guess.
On a Victorian or Edwardian terrace with a rear outrigger, an L-shaped dormer wraps the main rear slope and the back addition into a single continuous structure. It is the only way to get two bedrooms plus a bathroom out of a narrow London-style terrace loft. The junction between the two arms is where these live or die — it needs a properly designed valley and a single continuous membrane.
Key specification
| Configuration | Main rear dormer + outrigger dormer |
|---|---|
| Typical footprint | 18m² – 30m² gained |
| Critical detail | Valley junction and continuous membrane |
| Structure | Two ridge beams plus valley beam |
Planning and building control in Greater London
Getting the consent route right at the start saves months. We establish whether it is permitted development, a lawful development certificate or a full application on the first visit.
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 Greater London use us
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.
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.
Other dormer work in Greater London
- Lead & Zinc Dormer Roofing in Greater London
- Pitched Roof Dormers in Greater London
- Shed Dormers in Greater London
- Eyebrow Dormers in Greater London
- Bungalow Dormer Conversions in Greater London
- Dormer Window Replacement in Greater London
- Aluminium Dormer Windows in Greater London
- Dormer Cladding in Greater London
FAQs
L-Shaped Dormers in Greater London — FAQs
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.
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.
Find out what your roof will take
A free measured survey in Greater London tells you what is achievable, what it needs, and what it costs — before you commit to anything.