Hoping someone might be able to advise, or at least give an opinion on a party wall matter that seems to be going awry...
We're having a rear and side extension. Build will be within 3m of next door's foundations so party wall agreement was set up and signed. Neighbours were slightly prickly over it, and also objected to our plans but permission was granted nonetheless. So relationship not great.
We are fully detached, they are fully detached. Between our two houses, we each have a garage, both level with the front of the house. They are also both free-standing structures with about 6 inches between them. The edge of their garage is the boundary. Our garage sits 6 inches inside our land. The street is also on a hill and their whole property sits just above ours.
So, in order to build, we took down our garage (very carefully, brick by brick). As it came down, it revealed that their garage wall (which couldn't have been seen due to only 6" gap) was a total mess. The mess is old and decaying, clearly has been like that for a long time. The floor of their garage is about a metre above our ground level, due to the hill. It's clear that whoever built it, did a terrible job (their garage was built after ours). It has no foundation, the floor sits on a rickety pile of paving slabs, and they covered this with vertical paving slabs, stuck in with cement to create the garage wall. One of these slabs had come away over the years and when we took the garage down (which had been holding the loose slab in place) it revealed the pile of slabs and the void under their floor. The floor of their garage was made from an old brick wall, laid on its side. I mean, it's a really shoddy job! Nevertheless, it's survived at least the 15 years we've been here.
So, we're about to dig the foundations for the side extension (which run parallel to the boundary but 1m away from it) when they come tearing out of the house saying we've damaged their wall (?!) and if our digging (which is going to be done slowly by hand, 1m at a time... dig/fill/dig/fill) makes their wall fall down we are liable and they'll take legal action.
Now, I get that we are responsible for ensuring no harm comes to their property, and for making sure it's left as it was when we started, I have no problem with that. But if they had built their garage properly in the first place, none of this would have happened. We could also get another paving slab, cement it into the gap in the wall and presto... it's just how it was!
But they are now demanding we under pin their garage. And what's more, the party wall surveyor is suggesting that this is the best course of action too. We're waiting on precise quotes but it ain't gonna be cheap! Is this reasonable? What is the point of underpinning a piece of crap building?
Our builder is convinced nothing will happen if he cracks on with our build (good bloke, we trust him). So we could just ignore them and hope for the best. But what's the worst case scenario if we do this?
If it weren't for the fact that we need to crack on with our build, I'd call the council and get a dangerous building notice slapped on it but that could take weeks to resolve.
WWYD? Any ideas to throw into the pot would be appreciated!