Our neighbour is planning a basement next door: our buyers are v anxious...

[Elibean]

...and its slowed down our sale at the crucial moment

Neighbour wants party wall agreement signed, but obviously we've informed our buyer and he's now asking for party wall surveyor (I would too).

Here's my question: we're not joined, there is a garden wall between their side extension and our garden, but our buyer plans to build a side extension at the same time as the basement building is going on - does anyone know if this is likely to cause a problem? Would vibration from their excavation affect foundation building on our side of the fence?

I know those are probably only really answerable by the surveyor, but have no clue about basements (be the first in our road, though many in adjoining roads) or what problems can arise as a result of their creation.

And am getting v v frustrated by the whole thing

And yes, I'm the same person who wants to put in an offer on a sealed bids house - beginning to wonder if its worth it!

basically you have to be sure that the building of a basement doesnt compromise whether or not your house will stand up. if its two metres away then it should be ok. but if new buyer wants to build extension close to where basement i suppose it might not be viable if a basement exisited close by or if it is viable would only be with extra reinforcement. does that make sense. poor you!

How old is your house? It is very likely that the basement will go deeper than your foundations which means there is a potential for problems. A foundation for a new extension might need to be deeper than would normally be required because of the basement. Tbh if it was me I would want to see full structural calculations (rather than the word of a party wall surveyor) to put my mind at ease if I was buying (or staying if you don't sell!)

Its Edwardian. The party wall surveyor (chosen by our buyer, not the neighbour) said on the phone that he didn't think there would be a problem, that the works could run alongside...but he hasn't seen the properties yet, of course.

I think the main concern is soil slippage? There would be a couple of feet between their external wall, and our buyer's new extension external wall, if that makes any sense. But not much more.

Ugh.

GrapefruitMoon, do basements often mean new builds nearby need deeper foundations? Can't quite figure out why that would make a difference (probably being dim here...)...