Subsidence, loft conversion, and insurance

[primefactor]

We're looking to buy a flat and the building survey showed some evidence of recent subsidence, so the surveyor did not recommend going through with a loft conversion (or possible dormer extension) we had planned if we purchased it. He said he couldn't guarantee it wouldn't make the problem worse.

So the question is, if we did a small loft conversion (leaving out the en-suite and dormer extension) and did everything we could to reinforce/distribute the weight, but it still worsened the subsidence, will insurance refuse to cover a claim? Anyone have any experience? We're going to hire a structural engineer for a second opinion, but we think no one will offer any guarantees either way--seems like a "try it and find out" sort of nightmare.

If the subsidence is recent, what measures are currently in place to monitor it? I believe that monitoring can take a year or so to ascertain the severity of the subsidence and then there would be recommendations on how to remedy it, i.e. underpinning? I think I would want assurances that the "recent subsidence" was being dealt with by the current owners before I purchased and went ahead with a small loft conversion. Properties with subsidence can be expensive to insure so I would want this looked into too.

I would walk away. Sound like a lot of unknowns that could potentially be very expensive and problematic

The current owner is not aware of the subsidence--apparently the signs are very minor, to the point where the mortgage valuation did not even notice them. Maybe our surveyor was being over-cautious? Is it worth paying for a second opinion or getting a structural engineer out?

Lucky escape imho. I wouldn't touch it with barge pole.

If the subsidence isn't already dealt with I would avoid purchasing - you will have difficulty getting any insurance and mortgaging may be problematic as well. Any movement would need to be properly assessed before being dealt with.

The vendor needs to be made aware of this potential massive problem. They will have difficulty selling their house until it is all sorted and dealt with which could take a couple of years.

Walk away. Do not get a structural engineer in - this is the vendor's problem not yours.