party wall extension issue - any surveyors please?

[tropicalfish]

My mum's next door neighbour wishes to build a ground floor extension using my mums wall as their side wall. Their justification for this is that as my mums extension wall goes over their boundary they are entitled to this. They think it goes over their boundary by 10cm in some places.
My mum had an extension built maybe 20 years ago which 'went over the boundary' which is when this problem occurred.
My mum is concerned about whether this is a good idea with the neighbour putting in electrics and possibly undermining the wall and potential noise issues because the wall will be less thick than if the neighbour added their own wall as the side wall instead of just using hers.
Q - Do you think the neighbour can just use her wall just because it goes over her boundary, even without her consent?
Q - should she appoint a surveyor to resolve this issue?

This problem arose when a new neighbour moved in and wanted to build their ground floor extension.

Many thanks, my mum is really worried about it.

You need to get a Party Wall surveyor involved (at their cost). It's not alright for them to just 'use her wall' - even if it wasn't over the boundary, you need to have a party wall agreement in place if you are doing structural work to a neighbour's wall (imagine working in a terrace/semi for example) so that if any damage occurs to your mother's property, there are procedures/agreements in place to protect her property.

I would appoint a surveyor that they will pay for. I would not sign the party wall agreement as she will be more protected Ida surveyor is appointed. She can ask for payment to use her wall but might not be worth it in terms of neighbourly relations. Any damage to her house would need to be rectified. The fact her wall goes over the boundary is neither here not there as it does make sense to use it.

As a surveyor, if it was my house, given the boundary issue, I would want a party wall surveyor on board before any work started....

Are you semi-detached and is this wall of your mother's extension a continuation of the party wall between both houses? That would establish if it is an extension of a party wall and therefore a party wall itself.

If they build using it they should use a party wall agreement and a party wall surveyor of your choice could represent your interests. They would have to pay for this.

Sorry, should say not a surveyor.

Several issues to consider here:
Is your Mums wall over the freehold boundary and if so by how much.
Can your mum claim the land as her own freehold under land registry rules- which is a possibility.
Detail of neighbours proposals and whether planning consent needed.
Building regulations- is wall suitable for the proposed use, it might not have appropriate foundations.
Party wall agreement, yes this would potentially be required.

I suggest your Mum calls the RICS (royal institute of chartered surveyors) free helpline which gives 30mins free advice. Just on this post info, I'd say that the first thing to resolve is the boundary issue, which may involve your mum instruction her own surveyor, and or solicitor before moving to the party wall building issue, where you may be able to have the neighbour proposing the work cover the fees for the party wall agreement. Hope this helps..

hi,
Thanks for everyones reply.
The wall is alongside the boundary but breaches it by 10cm in some places. Its not a party wall, just the side wall of her own extension. But perhaps I dont understand what a party wall is.

They needed her to sign something before building work. I got the impression that it was because they were building along the boundary (although on their side) I dont know if this constitutes signing a party wall agreement.

I will ask her to call rics.
Thanks
Soofia