Loft conversion company in London.
Dormer loft · a zinc rear dormer, built by NUCompleted work, photograph
Dormer lofts and mansards for London houses. Designed, priced and built by one team.
A loft is a structural job before it is a room.
A loft conversion adds rooms in the roof, with a dormer or a mansard. We are NU Projects, design and build in Fulham SW6 since 2010. A loft runs £215 to £425 a sq ft, construction only. Call 020 7731 6841, and a budget estimate typically follows within seven days.
A loft is a structural job before it is a room. The steel, the roof and the stair are settled first, on the drawings.
A dormer adds a box to the rear roof slope. A mansard rebuilds the roof for more volume. We choose between them through design and planning review.
Head height is measured before the design is fixed. It must allow for insulation, structure and the finished floor.
The new stair takes space from the floor below. We draw it first, because it shapes every room around it.
One team handles planning, building control and party wall notices. The same team builds it, under one contract.
Already have an architect or designer? We build to their design, and work with them through to handover.
What the work includes
- Rear dormers, L-shaped dormers and mansards
- Structure, stair and head height settled on the drawings
- Planning, building control and party wall notices handled
- Bathrooms, heating and ventilation designed in
- Fitted eaves joinery by Cochrane Bespoke, where specified
- A defects period and aftercare from the same team
- Loft conversions by area
- Loft conversion in St John’s Wood, Loft conversion in Highgate, Loft conversion in Fulham, Loft conversion in Marylebone, Loft conversion in Notting Hill, Loft conversion in Chelsea
- What it costs
- See a range in a minute. Then send us the address for a proper number. Open the calculator
- Where we work
- Fulham, Chelsea, Kensington, Knightsbridge, Belgravia, Mayfair, Notting Hill and Holland Park, Chiswick, Wandsworth, Putney and Barnes, Hampstead and St John’s Wood, Weybridge, Cobham and Oxshott, South Kensington, Marylebone, Bayswater and Maida Vale, Pimlico and Westminster, Battersea and Clapham, Richmond, Twickenham and East Sheen, Islington, Highgate and Primrose Hill, Greenwich, Dulwich, Camden, Wimbledon, Bermondsey, Brixton, Ealing, Acton, Hammersmith and Brook Green, Earl’s Court, Queen’s Park and Kensal Rise, Fitzrovia and Bloomsbury
The stair is drawn first. It decides every room around it.
From the roof survey to the finished room.
- 01
Survey and head height
A measured survey of the roof. Head height and floor area tested first.
- 02
Dormer or mansard
The roof form chosen through design and planning review, for your house.
- 03
The stair and the structure
Stair position, steel and load paths settled on the drawings.
- 04
Consents and notices
Planning or permitted development, building control and party wall notices handled.
- 05
The cost plan, then one contract
A price built line by line from the drawings. Provisional sums named, not buried.
- 06
Build, reports and handover
A report every week, with photographs. Then a defects period and aftercare.
Ten checks before you appoint a loft conversion company.
- 01
Comparable completed lofts
Ask for finished conversions on the same kind of house. A suburban dormer says little about a mansard.
- 02
Who does the structural design
Ask who designs the load paths, the roof alteration and the steel. Then ask who checks it.
- 03
The planning route for your house
A mansard almost always needs permission. A conservation area can remove permitted development rights.
- 04
Party wall notices, served on time
Steel tied into a shared wall engages the Party Wall Act. Late notices delay terraces most.
- 05
Head height, before you commit
Ask for the measured height and usable area. Both must allow for the full build-up.
- 06
Where the stair lands
The stair takes space from the floor below. Ask to see it drawn before anything else.
- 07
Services integrated, not extended
A top floor bathroom needs pressure, drainage and heat. Ask if the existing system copes.
- 08
Insulation, ventilation and overheating
Ask how the roof is built up. Ask what stops it overheating in summer.
- 09
Finish and joinery
Eaves need fitted storage. Ask who draws and makes it, and whether it is in the price.
- 10
Handover and aftercare
Ask for the certificates and the defects process. Ask who to call two winters later.
What a loft conversion costs in London.
£215 to £425a sq ft, construction only. Our loft band.
£90k to £140kMain dormer loft. A project total, from our 2026 cost guide.
£140k to £220kMansard loft. A project total, from our 2026 cost guide.
Which figure applies depends on the roof, the stair and planning.
A loft bathroom, and work to the floors below, are priced as separate lines.
Professional fees, statutory costs, party wall, contingency and VAT are separate. Ranges are guide prices, not fixed quotations.
Dormers we built, and rooms under the roof in Fulham.
What owners ask before converting a loft.
Further reading, from the journal
How much does a loft conversion or mansard cost?
A loft runs £215 to £425 a sq ft, construction only.
Roof structure, stairs, headroom, roof form, bathrooms and floor work all set the budget.
The finished loft room is only part of the construction scope.
Use our build cost calculator for a range built from our own rate card.
Is there enough headroom for a loft conversion?
A measured section tests usable standing height, floor buildup, insulation and stair arrival. Roof height alone does not tell you how useful the finished room will be.
A loft runs £215 to £425 a sq ft, construction only.
What is the difference between a dormer and a mansard?
They create roof accommodation in different ways and change the external form differently. We choose the roof approach through design and planning review, not just floor area.
Where should the loft staircase go?
Its position affects the floor below as well as the loft.
We consider headroom, circulation, room loss and the escape strategy. This happens before bedrooms or bathrooms are fixed in place.
Can I add a bathroom in the loft?
We check hot and cold water, pressure, drainage falls and ventilation. Structural loads and the layout are checked at the same time.
The position can have knock-on effects on the floors below.
Will a loft conversion require changes below the roof?
It may affect stairs, ceilings, service routes and the fire strategy on existing floors. We include those changes in the scope and programme from the outset.
How can a loft stay comfortable in summer?
We consider roof insulation, glazing area, shading and ventilation together. Any cooling proposal needs space, power, condensate drainage and room for outdoor equipment.
Do I need planning permission for a loft conversion?
Some lofts are permitted development and some are not.
A mansard almost always needs planning permission.
An Article 4 direction or a conservation area can remove those rights.
We check the route against your actual address, before design starts.
Will you build to my own architect’s design?
Yes. Already have an architect or designer? We build to their design.
We price their drawings line by line, then work with them through to handover.
Tell us about the loft.
Your name and one way to reply are enough. It goes straight to the studio.
- Already have an architect or designer? We build to their design. Working with your designer