Timber Dormer Windows in Dorset
If you are weighing up timber dormer windows in Dorset, we survey the roof, tell you what is actually achievable, and price it properly before anyone commits.
Timber Dormer Windows — indicative geometry
Timber Dormer Windows for Dorset homes
Most of the dormer work we take on around Dorset 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.
Timber gives you the narrow sections and the moulded detail that period roofs need, and modern engineered laminated stock is dimensionally far more stable than the solid softwood it replaced. Factory-applied microporous paint or stain gives 8–10 years before recoating. On a front elevation in a conservation area it is very often the only material that will be approved.
Key specification
| Timber | Engineered laminated softwood or hardwood |
|---|---|
| Finish | Factory microporous paint or stain |
| Repaint interval | 8–10 years |
| Sightlines | Slimmer than uPVC or aluminium |
Planning and building control in Dorset
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 Dorset 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.
Book the survey, get the fixed written price, and decide in your own time. Nothing about that process commits you to anything.
Other dormer work in Dorset
FAQs
Timber Dormer Windows in Dorset — 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.
Can you match my existing roof tiles?
Usually. Most common clay and concrete profiles are still in production or available reclaimed, and we source a match at survey stage so you see it before work starts. Where a discontinued profile cannot be matched exactly, we normally recommend taking tiles from a less visible slope for the dormer and using the closest new match on the hidden elevation.
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.
Find out what your roof will take
A free measured survey in Dorset tells you what is achievable, what it needs, and what it costs — before you commit to anything.