Projects

Party walls for rear and side-return extensions

Kitchen extensions are the most common party wall job south of the river. Most need a boundary wall notice, an excavation notice, or both.

Section 1 · 1 month
Section 6 · 1 month
Often section 2 too

Side-return extensions

Most Victorian and Edwardian terraces in South London have a narrow passage beside the back addition. Filling it in usually means building a new wall on, or right up to, the boundary with next door's passage or back addition. That is a section 1 notice. The foundations for that wall will almost always be close to next door's and often deeper, which brings in section 6 as well.

Rear extensions

Building out across the back of the house means new footings near the boundary, and usually a section 6 notice. If you are raising or building onto the garden wall between you and next door, or cutting into the shared wall to take a beam where the old back wall is removed, that is section 2 work too.

On the boundary, or just inside it

Astride the line: needs your neighbour's written consent. The cost is then shared according to how each of you uses the wall.
Wholly on your land: you can build up to the line. If the footings need to project under next door's land, the Act allows it at your expense, with compensation for any damage.

Foundations on clay

Building control usually asks for deeper foundations on clay, particularly near trees. That often takes a new extension's footings below next door's older, shallower ones, which is exactly when section 6 applies. We look at the engineer's foundation design, any nearby trees and next door's foundation depth before the award is drawn up.

What we check

Foundation depth and type compared with the neighbour's.
Drains near the boundary, especially shared runs at the back of terraces.
How the new wall meets next door's wall, and the flashings and gutters along the boundary.
Steel beams into the party wall where the original back wall comes out.
Protection of next door's garden, fences and windows during the work.

Questions people ask

Do I need a party wall notice for a single-storey extension?

Often, yes. If the new wall is on or up to the boundary, or the footings go deeper than next door's within 3 metres, notice is needed even for a small single-storey job.

We live in a detached house. Does the Act still apply?

It can. The excavation rules apply to any neighbouring building or structure within 3 or 6 metres, not just to attached houses.

Can my neighbour's surveyor ask for trial holes?

They can ask to know how deep next door's foundations are, and a trial hole is the usual way to find out. It often saves argument later.