Neighbours extension- damaged caused- cellar flooded

[sundowners]

Hi all,
My mother lives in Victorian semi. Her neighbours (she is attached to) have for the past year carried out a major extension, basically gutting the inside of their house which they had tuned into 2 x flats for the past 20 years, adding a kitchen extension and removed the entire front of the house to carry out all the works. My mum lived next to this building site for the past year, meaning her lockdown when she was shielding was next to a massive building site, had scaffolding in her back garden/back garden wall was knocked down as she kindly allowed them to do- (meaning we couldn't visit with kids post lockdown as so unsafe) now its in its final stages there have been lots of issues, a lot to do with an awful landscaping company they hired who did such a poor job with the fencing both my mum and the other neighbours are seriously unhappy.

Anyway...we were just hoping to finally see the end of it all and at least let her get her house and garden back for Autumn/Winter now the builders have packed up.
Over the weekend her cellar flooded. She's lived there 40 years and her cellar has NEVER flooded before or had any damp issues. Next door has applied for a basement extension, got rejected but I know she's made some changes to it as she has now a gym down there.

So its no coincidence that only now, after a year of intense building works on the house next door my mum is attached to- her cellar floods. The neighbours at first organised a company to come out to pump out the water/dry it out. But over weekend its flooded again, and the fans left down there caused the electrics in the whole house to blow and my mum was without electricity for Sunday morning until she could finally switch it back on. She's written to neighbour again and they have just sent an appallingly rude response refusing to accept the flooding is anything to do with their building works, saying they wont be doing anything else and instead attempting to put my mums basement as the cause for their basement also flooding!!

Please anyone with any knowledge help, anyone who knows building regs/ basement flooding issues/has been involved with similar, any advice so appreciated.

Does she have a party wall agreement?

Africa thanks- yes she does would that help with this specifically though?

Next door has applied for a basement extension, got rejected but I know she's made some changes to it as she has now a gym down there.

The builder responsible for digging out the basement has obviously not done a proper job. The neighbour can't wash her hands of it and you may need to go down the legal route.

Check with local council if they had planning permission to dig down. If not that's a breach and they will have to remove it. Doesn't help your poor mum in the short term I'm afraid.

sundowners a party wall agreement means that any damage done is down to her neighbours to put right at their expense.

Thanks sunshinesupermum she hasn't actually done an extension (as far as we know) the existing cellars are already very deep/large. So my mums is sued for storage etc/old furniture but does not have adequate flooring/ heating/ plaster on walls etc down there to make it actually habitable, I'm assuming her neighbour carried out superficial changes to hers so she can home her gym equipment.

I was horrified every time I'd go over/see the house during the extension as this beautiful Victoria 3 storey house was literally propped up buy a few poles/completely gutted- so I dont accept her version that is pure coincidence that for the first time in 40 years my mums cellar happened to have been flooded- after enduing a year of intense budding works from her attached neighbour.

If your mum has a party wall agreement, the surveyor acting for your mum should visit and ascertain whether the flood damage is due to the works. If it is, the neighbour has to pay to put it right.

Does you mum have legal aid through her house insurance? If so, it might be worth giving them a call

Yes As above, get the surveyor round to look

She needs to involve her insurance company.

It’s possible that a spring has just sprung up. This unfortunately happened to a flat I own. We had to install a pump to get rid of the water when it appears. Hopefully this is not the case for you.

Has your Mum contacted the surveyor who did the PWA on her behalf?

sundowners worth checking with building control at your council. Separate dept from planning who would have to sign off on major work. Sounds like neighbour did a short cut after pp was denied. There would have been good reason for the denial which will be available on planning documents at the council.