What We Help With
Rear dormers
The most common dormer type, extending the rear roof slope outward to create a flat vertical wall and maximise headroom for a bedroom or bathroom.
Side & box dormers
Suited to terraced and semi-detached properties where a side extension adds width without altering the main roof profile as dramatically.
Rooflight-only conversions
Velux-style windows fitted into the existing roof pitch — the fastest, least disruptive way to bring natural light and limited extra headroom into a loft space.
Structural opening & headroom assessment
We measure existing ridge height and headroom at the proposed stair head before recommending dormer vs rooflight, so the decision is based on your actual roof, not a generic rule of thumb.
External finish matching
Cladding, tiling and brickwork on a new dormer are matched to the existing roof and elevation, so the addition doesn't look bolted on.
Planning route guidance
Dormers more often require a formal planning check than rooflights, particularly on street-facing elevations or in conservation areas — we confirm which route applies before design work begins.
Common Problems We Fix
Existing headroom too low for a rooflight conversion alone — needs a dormer to be genuinely usable.
Previous dormer with poor flashing detail — common source of leaks around the dormer cheeks and roof junction.
Rooflights fitted with inadequate flashing or seals — leading to water ingress during heavy rain.
Dormer cladding that doesn't match the existing roof material — affects both appearance and weatherproofing.
Undersized structural opening for the intended dormer — requires additional steel or joist work to correct.
Frequently Asked Questions
What's the real difference between a dormer and a rooflight conversion? +
A rooflight keeps the existing roof shape and adds windows within it — quicker and cheaper, but less additional space. A dormer extends the roof outward, adding standing headroom and floor area, but involves more structural work.
Will a dormer need planning permission? +
Often, particularly on a front or side elevation, or in a conservation area. Rear dormers on standard properties more commonly fall under Permitted Development. We check this for your specific address.
How much extra space does a dormer actually add? +
This depends on dormer size and roof pitch, but a typical rear dormer can add several square metres of full-height floor space compared to a rooflight-only conversion.
Can I combine rooflights and a dormer in the same conversion? +
Yes — this is common, using a rear dormer for the main headroom and rooflights elsewhere (e.g. over a stairwell or in a smaller room) for additional light without full dormer construction.
How long does a dormer installation take compared to rooflights? +
Rooflight-only work is typically completed in days. A dormer, including structural opening, roofing and external finish, usually takes several weeks as part of a wider conversion programme.
Will scaffolding be needed for rooflights? +
Usually yes, for safe roof access even on smaller rooflight jobs, though the scaffold period is much shorter than for a full dormer.
Ready to compare your options?
Speak to our technical team for a headroom assessment and recommendation.