Party wall agreements explained

If your extension, loft conversion or basement work affects a shared wall or is close to a neighbour’s boundary, the Party Wall etc. Act 1996 probably applies. It sounds daunting, but handled early it is straightforward and it protects both you and your neighbour.

When you need a party wall agreement

• You are building on or into a shared (party) wall, for example a loft conversion or a rear extension tied into next door.
• You are excavating foundations within three metres of a neighbouring building and deeper than their foundations.
• You are cutting into a party wall to take a beam, or raising or rebuilding it.

How the process works

You serve a party wall notice on the affected neighbours, usually one to two months before work starts. They can consent, or dissent and appoint a surveyor. If they dissent, a party wall surveyor (or one each) prepares a schedule of condition and a party wall award setting out how the work proceeds. Most cases settle amicably.

What it costs and how long it takes

If neighbours consent, the cost is minimal. If a surveyor is needed, budget from a few hundred pounds into the low thousands depending on complexity, usually paid by the party doing the work. Allow one to two months, which is why we start it early in the programme.

As your design and build team we flag party wall requirements at the design stage and coordinate the notices, so it never holds up your start on site.

Frequently asked questions