Extensions in Marylebone.

Marylebone · W1 · Marylebone listed apartmentCompleted work, photograph

Marylebone is apartments first, in Georgian terraces above shops. Extra space usually comes from within, the mews or the roof.

Get a cost estimate Call 020 7731 6841

Finding space inside the walls.

Grade II: Our Marylebone apartment sits in a listed building
Mezzanine: Space found inside tall Georgian rooms
W1U · W1G · NW1: Terraces, mews and estate land

NU Projects is a design and build company in Fulham SW6, founded in 2010. We handle house and kitchen extensions in Marylebone W1, under one contract. A rear kitchen extension typically runs £160k to £250k. A side return extension typically runs £140k to £220k. Call 020 7731 6841, and a budget estimate typically follows within seven days.

We renovated a first floor apartment in a Grade II listed Marylebone building. Its rooms are tall.

Rather than extend outward, we found space inside. A spiral stair now rises to a mezzanine wardrobe.

That is often the honest answer here. Most houses are apartments, with no garden to build into.

Mews houses behind the main streets can sometimes gain more. Much of the land belongs to large estates, whose licence comes first.

Westminster has over 11,000 listed buildings. Inside work to one needs listed consent, like the outside.

What the council allows in Marylebone.

Council: City of Westminster, for planning and listed building consent.
Conservation: Most of Marylebone is conservation area. Westminster has 56 such areas.
Listed interiors: Plasterwork, chimneypieces and shutters are part of the listing.
Butterfly roofs: An unbroken run of them normally rules out a roof extension.
Lower ground: Policy 50 allows one storey below the lowest original floor.

Source: Westminster’s City Plan, January 2026 edition, Policy 50. Read on 16 October 2026. Policies change, so we read them again for your address.