House
extensions
in West Hampstead, NW6

Policy 2 of the Fortune Green and West Hampstead plan expects extensions and infill to be in character and proportion with their setting, including the relationship to adjoining houses.

The plan, adopted by Camden in September 2015, applies alongside Camden's own policies.

Residents widely prefer red brick or London stock brick, the plan records, and grey-brick buildings have proved unpopular.

For a rear extension that usually means brick to match the house, or a lighter glazed structure that clearly reads as an addition.

Source: Fortune Green and West Hampstead Neighbourhood Plan (adopted by Camden, September 2015)

Camden's Home Improvements guidance asks a rear extension to stay subordinate to the house in location, form, footprint, scale and detail, and to use sympathetic materials.

Neighbours' daylight is tested at 45 and 25 degrees, or through a BRE study.

Side extensions should generally stay single storey, and a garden of reasonable size should remain.

For a flat roof, Camden prefers a biodiverse green roof over sedum, with a 100mm substrate.

Source: Camden Planning Guidance: Home Improvements (January 2021)

Rear extensions should not spill excessive light onto neighbours, including flats above in a divided house.

Rooflights on a single-storey extension work best set back from the house or in obscured glass.

We show the extension at night on the drawings as well as by day, because a large rooflight over a kitchen can be the brightest thing in the gardens after dark.

Source: Camden Planning Guidance: Home Improvements (January 2021)

On a terrace with a back addition, a side-return extension fills the narrow passage beside it and widens the kitchen. A wraparound goes further, combining the side return with a rear extension across the full width.

The deeper and taller the extension, the more it affects the neighbours' light and the garden, so we draw the smallest version that meets the brief first, and add depth only where the daylight tests allow.

Camden's guidance asks for a preliminary assessment of the house before extending at ground level, looking at the existing rear and any earlier extensions and how visible they are.

Source: Camden Planning Guidance: Home Improvements (January 2021)

Send the address, photographs of the back of the house and the garden from both ends, and any drawings or consents from earlier work. If the neighbours have extended, photographs of their extensions help us show the council how a new one would sit in the row.

Tell us how the extended room will be used: a kitchen and dining space, a family room or a study each need different light, heating and storage, and that changes the shape of the extension.

Mention any trees in or near the garden, any known drains or manholes and whether the property is a flat or a whole house, so the survey can confirm them before design starts.

If you have a budget in mind, share it early: it lets us say at the first visit whether a single-storey rear extension, a side return or a wraparound is the right scale for the money.

A rear extension in a West Hampstead terrace is seen from several gardens at once. We suggest showing the neighbours on both sides the drawings before the application goes in, and we draw the boundary wall, the gutter and any new parapet so that the party wall notices and the planning drawings describe the same thing.

It avoids objections that come from a misunderstanding, and the party wall stage starts from an agreed picture of the work.