Aluminium Dormer Windows in Cardiff
Our teams install aluminium dormer windows throughout Cardiff, handling structure, weatherproofing, glazing and finish as one job with one point of contact.
Aluminium Dormer Windows — indicative geometry
Aluminium Dormer Windows for Cardiff homes
Roofs across Cardiff 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.
A dormer usually has one window and one aspect, so every millimetre of frame you remove is daylight you gain. Thermally broken aluminium gives sightlines around 40% slimmer than uPVC for the same structural span, in any RAL colour, with a service life measured in decades. It is the premium choice on a contemporary flat roof dormer.
Key specification
| System | Polyamide thermally broken |
|---|---|
| Sightlines | Approx. 40% slimmer than uPVC |
| Finish | Any RAL, polyester powder coated |
| U-value | 1.4 W/m²K typical, 1.0 with triple |
Planning and building control in Cardiff
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.
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 Cardiff use us
Everything is priced from a measured survey, not a phone call — which is why our quotations tend to be the ones that still hold at the end of the job.
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 Cardiff
FAQs
Aluminium Dormer Windows in Cardiff — 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 Cardiff tells you what is achievable, what it needs, and what it costs — before you commit to anything.