Does the 3 metre Rule for Excavations Mean Anywhere Within a 3 metre Radius?

by: The Party Wall Surveyor


Some building works are about to start on a domestic property. The property is semi-detached with a pair of garages attaching the property on the detached side (now making this a linked house).
All the houses are built on the same line, so none of the properties extend beyond the other, unless they have done an extension..In this case, there are no extensions.

The first part of the work is to change the roof trusses to our garage (remembering that these garages are attached). The neighbour has a flat roof and we have a pitched roof.
The second part of the work is to build an extension 600mm our side of the boundary, which is technically 600mm away from the neighbours garage and then build out by 4m.

My questions are these..

  1. I am pretty confident that the alterations to the garage roof will require party wall notice..Is this correct..
  2. Although the extension will be over 3m away from the neighbour’s house, it will only be 600mm away from the neighbour’s garage and so I believe the 3m rule still applies (as this is the nearest structure)..Do you think this is correct also?


The work to the roof of the garage would be notifiable under section 2(2)(n) as you will be exposing a part wall to the elements (albeit temporarily) which was hitherto enclosed. I have to say that if you are doing a like for like replacement of the garage roof most owners probably wouldn’t serve notice (because they wouldn’t know it comes within the scope of the Act) but it is technically required.

You are correct about garages being classed as structures so if you are excavating below the depth of the foundations to the garage notice will be required under section 6(1).


Thank you for your response. I assume that the 3m rule for excavations means anywhere within in a 3m radius whether you build in front, behind or at any angle from the corner of this garage?


That is correct