Loft Extensions in London (283)

Planning a loft conversion in London? Whether you’re dreaming of a new bedroom, a home office, or just more space to breathe, we’re here to help.

Find rated loft conversion builders in London without the hassle

With Checkatrade, you can find checked loft conversion companies in London and get quotes from trades who cover your area, fast. No faff. Just a simple way to turn that empty attic into something brilliant.

Post your job in minutes or browse reviewed London loft conversion builders near you. It’s free to use, and you’re in control every step of the way.

What to expect from hiring a loft conversion builder in London

Loft conversions are one of the most popular ways to add space (and value) to a home. Here’s what you need to know:

Common loft conversion jobs in London

• Dormer loft conversions
• Hip-to-gable conversions
• Velux (rooflight) conversions
• Mansard conversions
• Bungalow loft extensions

Average cost of a loft conversion in London

Loft conversions:

Expect to pay £35928 on average, with prices typically starting at £23495 up to £54370.

Loft ladder installers:

Expect to pay £382 on average, with prices typically starting at £294 up to £505.

Loft window installation:

Expect to pay £1811 on average, with prices typically starting at £1259 up to £2651.

Roof light installation:

Expect to pay £2273 on average, with prices typically starting at £1229 up to £4142.

Dormer windows:

Expect to pay £1862 on average, with prices typically starting at £1153 up to £3053.

Explore our loft conversion cost guide for a detailed breakdown.

What’s included in a loft conversion quote?

• Design and structural plans
• Building work and insulation
• Stairs, electrics, plumbing
• Windows, flooring, and finishes

Extra costs to think about:

• Architect or structural engineer fees
• Planning permission (if required)
• Bathrooms or heating upgrades
• Underfloor heating or bespoke storage

How long does a loft conversion take?

Velux: 4 - 6 weeks

Dormer: 10 - 12 weeks

Mansard: 8 - 10 weeks

Loft conversions in London: Homeowners vs renters

If you own your home:

• You’re responsible for planning, permissions, and hiring.
• Check if you need planning permission; many lofts fall under permitted development, but not all.
• Building regulations always apply. A loft conversion without sign-off could cause issues later (including invalidating home insurance).

If you rent:

• You can’t carry out major work like a loft conversion.
• Speak to your landlord if you notice issues in the loft space (leaks, insulation problems etc.).
• If you spot an unregulated loft conversion, flag it with your landlord or letting agent.

Emergency loft conversion help in London

Need urgent loft work like a leak, collapsed ceiling, or unsafe structure? We’ve got you.

Search for emergency loft conversion services in London to find available trades fast.

Find a loft conversion builder for your job in London

Here are some common requests from homeowners and renters alike:

• Loft boarding or insulation
• Full loft extensions
• Velux or dormer installations
• Bungalow loft conversion design
• Loft conversion quotes
• Structural inspections or fixes
• Loft stairs installation
• Loft storage or lighting upgrades
• Fixing illegal or unregulated conversions

Use our request a quote feature; it’s a quick, easy way to get responses from loft builders covering your local area.