A loft conversion is the cheapest way to add a bedroom to a Glasgow house without losing garden — but the price depends almost entirely on which type of conversion your roof allows. This guide gives 2026 costs for Velux, dormer and hip-to-gable conversions in Glasgow, what the council requires, and where the money goes, based on how we price and build them.
What our prices include
All prices on this page are labour plus building materials — plaster, plasterboard, pipework and plumbing fittings, electrical cable and accessories, timber, plywood, adhesives, grout, sealants and fixings — and include VAT. Every quote is itemised line by line.
Not included (you buy these, or we can supply and add them to the quote): bathroom suite and tiles if an en suite is added, and any bespoke joinery or fitted wardrobes. You get our 10% trade discount at Topps Tiles, B&Q TradePoint, Wholesale Domestic and Victoria Plumbing.
Loft conversion cost in Glasgow 2026: the short answer
A Velux (rooflight) loft conversion in Glasgow costs £30,000–£40,000; a rear dormer £45,000–£60,000; a hip-to-gable with dormer £55,000–£75,000, all including VAT, drawings, structural engineer and building warrant, finished as a plastered, decorated bedroom with a proper staircase. Add £5,000–£9,000 for an en suite.
| Loft conversion type (Glasgow) | Typical cost inc. VAT |
|---|---|
| Velux / rooflight conversion — new floor, insulation, 2–3 roof windows, stairs, plastered and decorated | £30,000 – £40,000 |
| Rear dormer (flat-roof box dormer) — as above plus dormer structure and windows | £45,000 – £60,000 |
| Hip-to-gable + rear dormer (semi-detached and end-terrace) | £55,000 – £75,000 |
| L-shaped dormer (Victorian terrace with rear addition) | £60,000 – £85,000 |
| Mansard / full roof rebuild | £75,000 – £100,000+ |
| En suite shower room added to any of the above | + £5,000 – £9,000 |
| Drawings, engineer, building warrant (included above) | £3,000 – £5,000 |
Where the money goes on a dormer conversion (~£52,000)
| Item | Share of cost |
|---|---|
| Drawings, structural engineer, building warrant | £3,500 – £5,000 |
| New floor structure (steel beams + joists) — the floor you have is a ceiling, not a floor | £6,000 – £9,000 |
| Dormer structure, roof, cladding, windows | £9,000 – £14,000 |
| Insulation to current Scottish standards, roof windows | £4,000 – £6,000 |
| Staircase (bespoke, to fit the landing), fire doors, fire-rated ceilings | £5,000 – £8,000 |
| Electrics, heating extended, smoke alarms linked | £3,000 – £5,000 |
| Plastering, flooring, skirtings, decoration | £4,500 – £7,000 |
| Scaffold, skip, site set-up | £2,000 – £3,500 |
Which conversion does your roof allow?
- Velux — needs about 2.3 m of head height at the ridge already. Common in 1930s bungalows and villas across the southside (Newlands, Cathcart, Giffnock). No change to the roofline, so no planning permission.
- Rear dormer — the standard for 1930s semis and post-war houses where the ridge is high enough but the usable floor is narrow. Adds a full-height room and space for a bathroom.
- Hip-to-gable — for hipped-roof semis and bungalows; builds the sloping end up to a vertical gable, then a rear dormer. Biggest gain in space, biggest cost.
- Tenement flats — top-floor tenement lofts are usually shared common property. Converting one needs agreement from all owners and is rarely straightforward; ask before you plan around it.
Planning permission and building warrant
In Scotland a loft conversion always needs a building warrant from Glasgow City Council — structure, fire escape, insulation and stairs are all checked. Rear dormers within permitted development limits usually do not need planning permission; anything on the front elevation, in a conservation area, or on a flat does. Allow 8–12 weeks for drawings and warrant before work starts. We handle all of it; see our building warrant guide.
How long does it take?
Velux: 4–6 weeks on site. Dormer: 7–10 weeks. Hip-to-gable: 10–14 weeks. Most of the work is done from outside via scaffold, so you keep living in the house; the messy part is the week the staircase goes in.
What makes it cost more
- Moving the water tank or boiler out of the loft
- Roof timbers that need strengthening or a purlin removed
- Bathroom in the loft — soil pipe route and water pressure
- Staircase over an existing stair with no landing room
- Conservation area cladding or slate matching
How we price a loft
Site visit with a tape measure in the loft, then a written fixed price broken down by stage — structure, dormer, stairs, services, finishes — so you can see what an en suite or a second Velux adds before deciding. Stage payments, 12-month workmanship guarantee, full insurance.
Frequently asked questions
How much does a loft conversion cost in Glasgow?
£30,000–£40,000 for a Velux conversion, £45,000–£60,000 for a rear dormer, £55,000–£75,000 for hip-to-gable with dormer — all including VAT, drawings and building warrant, finished as a decorated bedroom.
Do I need planning permission for a loft conversion in Glasgow?
Not usually for a rear dormer within permitted development limits. You always need a building warrant. Front dormers, conservation areas and flats need planning permission.
Is my loft high enough?
You need roughly 2.3 m from the top of the ceiling joists to the underside of the ridge for a Velux conversion. Less than that and a dormer or hip-to-gable is the answer. We measure it at the site visit.
Can I add a bathroom in the loft?
Usually yes — £5,000–£9,000 extra for an en suite shower room, depending on where the soil pipe can run.
How much value does a loft conversion add in Glasgow?
An extra double bedroom with en suite typically adds 15–20% to a three-bed semi in the southside or north-west suburbs, which usually exceeds the cost.
Want a fixed price for your loft? Call 07568 582337 or book a site visit. Written itemised quote within 48 hours. See also loft conversions Glasgow and builders Glasgow.