Do we need to serve party wall notice?

[mothergooseinnorthwest]

Hi we are in a semi and plan to do a rear extension. We are leaving a 18mm gap between our new wall and the fence we share with the neighbour we are semi to so that our foundation doesn’t get onto their land.

From what I read online, unless our foundation is going to be deeper than our neighbours, we don’t need to serve party wall notice but our architectural technician who is also a party wall surveyor is strongly suggesting we do it.

My reasoning is our foundation is unlikely to be deeper as our neighbours foundation is for 2 storeys and ours is single. Plus, we should have similar soil being next door to each other?

Anyone else in similar situation who served party wall notice for excavation? Any good reason for that? there is a fee to have him serve it bit I am aware that we can do it ourselves.

Thanks.

When we did our extension we had to dig to find out how deep our neighbour's foundations were and also do a party wall agreement. I think of it's of your extension is within a meter of their property you need to do one.
We paid to have the agreement drawn up and the neighbours opted to appoint their own surveyor (which we had to pay for). This is their right.

The point is you dont know your foundations won't be deeper until your builder starts digging.

Should have added, we completed the notice ourselves and took it round. They were fine, we had kept them upto date with our plans throughout. They signed it and we got on with the work (it didn't apply in the end as the foundations didnt need to be deeper than theirs)

Thank you both.

@africa2go I think I will do what you did. Serve it ourselves as a catch it all, keep the neighbours informed form the very start. We have good neighbours so hopefully they wouldn’t want to appoint a surveyor of their own.