Damage to my house by neighbour's builders

OhDearyMe

Hi,
This is my first post here and I am hoping that someone will be able to help me.....
I live in a terraced house with a downstairs toilet and 'utility room' in what used to be a lean-to a the end of the kitchen, it was previously only accessible from the outside but one of the previous owners changed the access so that the utility room and then the toilet lead on from the end of the kitchen.
A few years ago (maybe four) one of my neighbours decided that they wanted to get their half of the lean-to demolished along with their kitchen and build a new one.
A good idea, one may think, but one day during the build I came home to find that there were cracks in the plasterwork in one of my walls, the one that is a the end of my utility room and which holds the door through which you go to the toilet. The remaining part of that wall which was part of my neighbour's house had been demolished (i imagine in as quick and brusk a manner as possible, going on some of the work that I did see being carried out) whilst I was out and therefore my wall no long had the support that it once did.
I went to explain this to my neighbours and to complain. They told their builder who came round to look and who unsurprisingly, said that it wasn't his fault. The fact that there were no cracks there before they arrived and now there were was of no interest to him. He refused to help me and left.
I was not sure what to do and being a single woman did not feel like I was in a position to argue my case. Not knowing what to do, I left it, hoping that the cracks would not get any worse.
Now a few years later, I find that the cracks have got substantially worse, some of them are now
5mm across.
There are many cracks in the end wall of the utility room (that leads to the toilet) and in the wall in the utility room that is attached to that wall which also looks like it is trying to detach itself from the ceiling (there is a crack over a metre long along the join between that wall and the ceiling). There are also many substantial cracks in the downstairs toilet, in a diagonal pattern and the wood cladding inside the downstairs toilet has gaps of several millimetres where it was once flush with the wall where it has also moved. It is almost as if the end of my house is falling off.
The door that I had sized especially to fit the doorway (which is narrow) no long fits in the hole as the doorway is no longer square.
In addition, in the past six months it seems like the floor in my bathroom above the kitchen has started to slope slightly.

So my question is - can I do anything about this without it costing me money? Especially given the time that has elapsed.
Someone I know through work who is a house builder said that I can claim under my insurance and that my insurance will claim under my neighbour's insurance as you would do if you had had a car accident and claimed on their car insurance. Will this work? Is there a period of time that one has to be able to claim for such occurrences?
What happens if my neighbours refuse to accept that the damage was caused by the builder that they employed?
I don't want to end up with some kind of issue with my insurance company insisting that my house is suffering from subsidence as I know that this increases insurance premiums.
One of my other friends said that his parents had a similar kind of problem and that their insurance company propped up their house.
Obviously trying to go after the builder now would be a compete waste of time, given that he was denying all knowledge at the time.
As far as I can see, the rear end of my property needs rebuilding, but I don't want to end up with a huge bill that I can't afford for something that is not my doing.
What can I do to find the best and most economical way (for me at least) for this problem to be fixed.
I also imagine that this would prove hugely problematic if I wanted to sell the property or rent it out and so I really need to get this fixed somehow.
I haven't yet called my insurance company but wanted to know what my position is before doing so, in case they try to get out of something that they should really take care of.
Apologies for the long post.
Any help would be gratefully received as it is getting to the point where I really need to get this fixed as I am worried what might happen.
Thank you in advance for any assistance you may be able to provide
Kind regards

sandsni

Do you have proof that the cracks weren't there before the neighbours' lean-to was demolished? Without it I think you'll have problems proving the builders were responsible, particularly after 4 years.


Hopefully someone else will be along soon who will be able to give you some more positive advice.

eddddy

If it were me, I would get a building surveyor or structural engineer to look at it. Unfortunately, this will cost a few hundred pounds.

They should be able to tell you what has caused it (e.g. whether it was the neighbour's building work, or something else) and what needs to be done to repair it.

You could then decide where to go from there. For example,...

If the report says it is due to negligence by the neighbour (or his builder), you may not be covered by insurance, so you may have to claim from your neighbour.

If the report says it is subsidence, you may want to claim from your insurer.

If the report says it is because of faulty workmanship when the house was built (which I think is unlikely), you probably don't have grounds to claim from anyone, and will have to cover the cost yourself.