Loft Conversions

Loft Conversions in Glasgow — 2025 Cost & Planning Guide

Velux, dormer or L-shaped — find out what's possible in your Glasgow roof, what it costs, and what planning you need.

Loft conversions: Glasgow's smartest space gain

For families who love their street but have outgrown their square footage, a loft conversion is often the smartest move in Glasgow. You add a bedroom (or two) and an en-suite without losing any garden, and you avoid the planning friction of extending into the rear.

The four loft conversion types

1. Velux / rooflight conversion

The cheapest and least disruptive option. The roof structure stays exactly as it is — you simply insulate, board out, add stairs and Velux windows. Best for properties with generous existing head height (many Glasgow Victorian terraces qualify).

2. Dormer conversion

A box dormer extends the roof outwards to gain head height and floor area. The most popular option for Glasgow 1930s semis and post-war stock where the original loft is too cramped.

3. Hip-to-gable

For semi-detached and end-terrace properties with a sloping side roof — converts that hip into a vertical gable wall, adding significant floor area. Almost always combined with a rear dormer.

4. Mansard

The biggest gain — replaces the entire roof slope with a near-vertical wall. Common on Glasgow tenement-style upper flats but requires full planning and significant investment.

Glasgow loft conversion costs (2025)

  • Velux conversion: £28,000–£40,000
  • Box dormer: £45,000–£65,000
  • Hip-to-gable + dormer: £65,000–£90,000
  • Mansard: £75,000–£110,000
  • En-suite addition: +£8,000–£14,000
Don't forget the staircase
The new staircase usually steals a corner of an existing first-floor bedroom. Factor in the cost of redecorating that room and possibly rejigging built-in storage.
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Estimate your Glasgow extension

Estimated cost range
£40,000 – £51,000

Includes labour, materials and standard fit-out. Excludes architect's fees, planning fees and building warrant.

Planning & building warrant in Glasgow

Velux conversions generally fall under PDR. Dormers, hip-to-gable changes and mansards almost always need full planning — and Glasgow City Council pays particular attention to dormers facing the public road. Whatever you build, you will need a building warrant: lofts must meet stringent fire-escape, insulation and structural requirements.

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Frequently asked questions

Velux-only conversions start around £28,000–£40,000. Dormer conversions typically run £45,000–£70,000. L-shaped or hip-to-gable conversions on Glasgow Victorian stock usually land between £65,000 and £95,000.