I am extending my detached house – why would the Party Wall etc. Act 1996 affect me?

You may have planning permission and/or Building Regulations approval, and now a Party Wall Surveyor has written to say your excavations near the boundary will be subject to Section 6 of the Act…

Beware of marketing letters from “Party Wall Specialists”!

There are a number of agencies who trawl through planning applications lists and offer their services to neighbours of applicants who appear to intend to build within 6m of the neighbours’ building. They usually just pick likely jobs, and don't usually bother to check so the work might not actually come under the Party Wall Act.

These firms exploit the fact that many building owners are totally unaware of the Party Wall Act, and that many neighbours do not talk to each other, so they use hard sell tactics on your neighbours to get them to sign up. They are nearly always unqualified and unregulated so they are pretty much untouchable by the authorities. See sample below

You are advised to take your own advice, checking to see if the work can be executed outside the Party Wall Act, perhaps with modifications such as designing shallower foundations, and the cost of the redesign is usually cheaper than the party wall surveyor's fees.

What does the Act say if I want to excavate near neighbouring buildings?

You must inform the Adjoining Owner(s) by serving a notice if you plan to either:

1) excavate for and construct foundations for a new building or structure, within 3 metres of any part of a neighbouring owner's building or structure, where any part of that work will go deeper than the neighbour's foundations

This is a typical worst case scenario, and it makes no difference where the actual boundary line is with respect to the two properties. If a neighbour’s building is less than 50 years old it’s a fairly safe bet that their foundations are at least 1m deep, so provided your designer does not anticipate the proposed foundations need to be more than the standard 1m deep, you have no obligation under the PW Act to notify your neighbour

or

2) excavate for and construct foundations for a new building or structure, within 6 metres of any part of a neighbouring owner's building or structure, where any part of that work will meet a line drawn downwards at 45° in the direction of the excavation from the bottom of the neighbour's foundations.

In this second scenario where your excavation is over 3m away, even if the neighbouring property is more than 50 years old which could mean the base of their foundations is only 600mm or less below ground level, and/or if the ground rises, it would be best to draw a cross-section to check that the 45° line does not cross your excavation especially if deep footings are needed in shrinkable soils and near large trees.

Generally in our experience this is very unlikely to be the case.

Other situations could be if a neighbour has a structure on the boundary line or even a drain run adjacent the boundary which could be damaged as a result of works you carry out. You must also inform the Adjoining Owner by serving a notice if you plan to build a wall wholly on your own land but up against the boundary line.

How to submit Notice if the Party Wall Act applies

Notice should be submitted in writing at least one month before commencement, which can take the form of a standard format which we can assist you with, together with a standard acknowledgement which your neighbour can sign. If the Adjoining Owner gives written notice within 14 days consenting to the proposed works, the work (as agreed) may go ahead. If the Adjoining Owner does not respond, or objects to the proposed work, a dispute is regarded as having arisen.

What happens if a dispute arises?

Both parties need to agree to appoint a Party Wall Surveyor to draw up a Party Wall Award that sets out the works and how they are to be carried out, alternatively appoint their own surveyors. More details can be provided on request.

Usually the Building Owner will have to pay all costs associated with drawing up the Award including the adjoining owner’s surveyor’s fees, if the works are solely for the Building Owner’s benefit.The average project typically costs around £2,000 for a Party Wall Agreement depending on the complexity