Advice needed please

[Onetraumaatatimeplease]

Hi all, apologies first of all if this is in the wrong place, but I really really need some advice.
I live in a Victorian terrace with an extension on the back. When I bought the house it was almost derelict and the walls of the extension needed to be rebuilt. However my next door neighbour has built his own extension onto the side of my house. As a result we left that wall alone. But now the render is cracking and the wall needs to be tied properly into the rest of the building. We have just had a quote to fix it for 10k. 10 effing k. If it was just a case of pulling the wall down and rebuilding it would be significantly less. Coincidently ndn put his house on the market just after he found out we were getting quotes. My question is, does anybody know where we stand legally, is he allowed to attach an extension to my house without permission (the house was empty when I bought it)
Thanks for any help

Where would I find out about third party wall agreements, would that be in the deeds? The solicitor never mentioned any problems or possible problems at all I have just had a quick look at the party wall act online. What's stressing me out is the fact that when I told him I was getting quotes for that wall within days the house went up for sale (and it's priced to go quickly) and I'm left wondering why, i may just be being paranoid but he used to be "in the trade".

Eh? There wouldn't necessarily be 'a party wall agreement in place' when you bought the house. If your neighbour was affecting what is classed as a party wall when he built his extension then there should have been a party wall agreement at that point, depending on when historically that was. A PWA entered into before you bought the house should have come to light during the purchase process.

I'd have a look at the council's planning portal and check whether your neighbour's extension complies with the planning permission granted (if applicable) or permitted development rules. You can speak to a planning officer for general advice and guidance.

If your neighbour hasn't followed the rules, he is on a sticky wicket trying to sell with the necessary permissions and agreements in place.

Why on earth did you not act when he started work on his extension? It is possible the cracks to the render on your wall could have been caused by your NDN's building work and he may be liable to put it right.

I would get the local authority Building control Officer out to have a gander at it. Take his advice from there.

The house was empty for 2 years plus when we bought it. We assume that his extension went up then. His is a single floor extension joined on to my 2 floor extension.

This is rather confusing - so you don't actually know when the NDN's extension was built? If it was when your house was empty then your solicitor should have made enquiries and checked whether there was a PWA.

This you need to check.

Thunderbolt is quite right - a prospective purchaser of NDN's house will want to check this out. It is in the neighbour's interest to resolve the situation with you, or he may find himself having to declare a dispute with you.