attic trap in Portsmouth (67)

Planning a loft conversion in Portsmouth? 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 Portsmouth without the hassle

With Checkatrade, you can find checked loft conversion companies in Portsmouth 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 Portsmouth 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 Portsmouth

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 Portsmouth

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

Average cost of a loft conversion in Portsmouth

Loft conversions:

Expect to pay £37346 on average, with prices typically starting at £23540 up to £58094.

Loft ladder installers:

Expect to pay £361 on average, with prices typically starting at £273 up to £486.

Loft window installation:

Expect to pay £2393 on average, with prices typically starting at £1658 up to £3566.

Roof light installation:

Expect to pay £2475 on average, with prices typically starting at £1171 up to £4674.

Dormer windows:

Expect to pay £1576 on average, with prices typically starting at £938 up to £2605.

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 Portsmouth: 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 Portsmouth

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

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

Find a loft conversion builder for your job in Portsmouth

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.