Most people ask us this first, so we built the answer into the page. Drag the ridge, pick your roof, and watch where a grown-up can actually stand. Then we come and measure it properly, free.
General guide only, not advice for your property. Measure from the top of a ceiling joist to the underside of the ridge; most lofts need around 2.2 m. New floors and insulation take some height, which is why we measure on a free survey.
Your roof shape and height decide most of it. Prices are sample ranges including VAT for a typical Birmingham semi or terrace; your written quote is fixed after the survey and drawings.
Windows set into the slope, new floor, stairs and insulation. Quickest and least disruptive, but only works when there's height to spare.
A box built out from the back slope, turning sloping ceiling into full-height room. Usually room for a double bedroom and a shower room.
The sloping side of a hipped roof is built up into an upright gable wall, usually with a rear dormer too. Common across Hall Green and Sheldon.
The back slope is rebuilt nearly upright with a flat top. The most space you can get from a low terrace roof, and it usually needs planning permission.
You stay living at home for almost all of it. Most of the work comes in from the scaffold, and the opening to your landing is only cut near the end.
We measure the head height, look at the roof structure and talk through what you want the room for.
45 minutesPlans, structural calculations and a fixed written quote. You see the room before anything is built.
2–4 weeks (sample)Building control application, party wall notices to neighbours where needed, and planning if your design needs it.
2–8 weeks (sample)Scaffold, steels, dormer frame, roof, then insulation, plaster and the new staircase last.
6–10 weeks (sample)Building control completion certificate, your guarantee paperwork, and a snagging visit after a few weeks.
Handover day
Image slot · dormer frame on scaffoldSample projects for this concept. On a real site each one links to a full write-up with drawings, weeks on site and the final cost range.
2.35 m to the ridge on a 1900s terrace. L-shaped dormer over the back addition, 8 weeks on site.
Hipped 1930s semi turned to a gable with a full-width dormer. 9 weeks, party wall agreed before start.
A tall gable at 2.8 m meant no dormer was needed. Three rooflights and a fitted desk, 5 weeks.
"They told us our ridge was borderline before we'd paid a penny, then showed us how a dormer fixed it. No surprises on the bill."
"Tidy every day, and the stairs went in on the week they said. Neighbours got their party wall letters early, which helped."
A general guide for England as of October 2026, not advice for your property. Wales, Scotland and Northern Ireland differ. Always check the official source, and we confirm the details for your house during the survey.
Signing the contract at home? You normally have 14 days to cancel under the Consumer Contracts Regulations 2013. Under CDM 2015 we take on the client duties for your domestic project. General information only, as of Oct 2026.
