Sitting room with navy walls, a fireplace and a chandelier.

Loft conversions in Mayfair.

Mayfair · W1 · Mayfair apartmentCompleted work, photograph

A Mayfair loft is rarely a family attic. It is usually a penthouse or a mews house.

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Mayfair roofs, above shops and apartments.

2019
Mayfair Neighbourhood Plan made
Policy 44
Listed fabric and period detail kept
W1
Georgian houses split into apartments

NU Projects is a design and build company in Fulham SW6, founded in 2010. We handle loft conversions, dormers and mansards in Mayfair W1, under one contract. A main dormer loft typically runs £90k to £140k. A mansard loft runs £140k to £220k. Call 020 7731 6841, and a budget estimate typically follows within seven days.

Mayfair’s Georgian townhouses are now mostly apartments, often stacked above shops.

A whole house is rare. So a roof project normally belongs to the top flat, or to a mews.

Planning comes from Westminster, beside the Mayfair Neighbourhood Plan of December 2019. Grosvenor’s licence often follows.

Policy 44 asks work on a listed building to keep its special interest. Roof timbers can be part of it.

Our Mayfair apartment refurbishment showed how many consents one building can hold.

What Westminster allows on a Mayfair roof.

Council
City of Westminster, whose City Plan dates from January 2026.
Neighbourhood plan
The Mayfair Neighbourhood Plan was made in December 2019.
Listed buildings
Policy 44. Work to a listed building must keep its special interest and period detail.
The estate
Grosvenor owns much of Mayfair. Its licence often sits beside council consent.
Apartments
Flats have no householder permitted development rights. Any roof change needs planning.

Source: Westminster’s City Plan 2026, Policies 43 and 44, and the Mayfair Neighbourhood Plan. Read on 3 October 2026. Policies change, so we read them again for your address.

Our work in Mayfair.

Pale kitchen with a sliding ladder and an open larder.

Mayfair·Apartment

Mayfair apartment

A Mayfair apartment we refurbished, in W1.

See the project

Completed work, photographs

What a loft conversion costs in Mayfair.

£140k to £220kA mansard loft. A project total, from our 2026 cost guide.

Access over a shopfront can shape the programme and the cost.

The guide figure is a project total.

Fees, party wall costs, contingency and VAT sit outside it.

Open the calculatorThe 2026 cost guideCan I build it here?

Can a Mayfair penthouse extend into the roof above?

Sometimes, with the freeholder’s licence and Westminster’s consent.

Flats have no permitted development rights, so planning is always needed.

A listed building adds listed consent.

Is a Mayfair mews house easier to extend upwards?

It can be, where the mews roofline is already varied.

An untouched row is judged as a whole and often refused.

What does the Mayfair Neighbourhood Plan mean for roof work?

It sits beside Westminster’s City Plan in every decision.

We read both against the building before drawing.

Does a listed Mayfair building limit what happens in the roof?

Yes. Policy 44 protects special interest and period detail.

Original roof timbers and top floor rooms may be part of that.

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