Dormer Window Repairs in Cardiff
If you are weighing up dormer window repairs in Cardiff, we survey the roof, tell you what is actually achievable, and price it properly before anyone commits.
Dormer Window Repairs — indicative geometry
Dormer Window Repairs 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 stain on a dormer ceiling almost never starts at the window. It usually starts at the apron flashing, the cheek-to-roof soaker, the back gutter or a split in the flat roof covering, and travels. We trace the actual water path before quoting, because replacing a window that was never leaking is the most common wasted spend on a dormer.
Key specification
| Common causes | Apron flashing, soakers, back gutter, split membrane |
|---|---|
| Diagnosis | Water trace before quotation |
| Rot repair | Splice or full replacement of sills and studs |
| Glazing | Blown unit replacement, any size |
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.
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 Cardiff
FAQs
Dormer Window Repairs in Cardiff — FAQs
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.
How disruptive is a dormer build?
Less than people expect, because most of the work happens above your ceilings and is reached from the scaffold. The noisy phases are opening up and installing steels, typically two to four days. Once the staircase is cut in there is dust and traffic through the house, and we sheet and protect the route for that period.
Do dormer windows need to be fire escape windows?
In a loft conversion, at least one window in each habitable room generally needs to meet escape requirements — a clear opening of at least 0.33m², minimum 450mm in both height and width, with the bottom of the opening between 800mm and 1100mm above floor level. We specify the opening lights to meet this as standard.
Do I need planning permission for a dormer window?
Rear dormers on a house often fall under permitted development, provided the dormer is set at least 200mm back from the eaves, sits below the ridge line, uses materials similar in appearance to the existing house, and stays within the volume allowance — 40m³ for a terrace, 50m³ for a semi or detached. Front-facing dormers, flats and maisonettes, listed buildings, conservation areas and any property with an Article 4 direction all need a full planning application. We check the constraints on your specific address before we quote.
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.
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.