I own a flat in the UK, in which I live. I own it. It's part of a block of 50 flats.

I have learned recently that there was a subsidence problem. A large tree has been drinking the water from under the building, which has started to move. Some walls show some cracks.

The freeholding company is talking with the insurance, trying to get underpinning work done.

My question is this: how serious can that be? Should I be looking to move flats because of this? Of course, I am not expecting someone to be able to answer definitively without seeing the building, but I am after a general case answer. What's the likely outcome, and what's the worse outcome?

In particular, can I be fairly certain that in the vast majority of cases, some underpinning will fix the problem? Or is it sometimes the case that a building is beyond hope, and therefore my flat could lose all its value?

  • 1
    Flagged as too broad. Best case scenario, nothing happens. Worst case, the building falls down. Only an engineer on site can assess the current state and make recommendations on how to proceed.
    – mmathis
    Aug 22, 2016 at 14:11
  • ...and it would be very hard to sell your flat while it's in a state of "known to have a problem, problem not fixed yet." I do kinda wonder about the tree getting blamed (i.e. is that accurate, or someone's off-the cuff explanation?) but indeed subsidence can range from no problem or a soluble problem on up to "there's a crater where a building used to be."
    – Ecnerwal
    Aug 22, 2016 at 17:09
  • The tree explanation is a serious one, after inspection by professionals. But I do not have color on the severity of the issue. From what you are saying, the worst case scenario is bad... I was hoping to hear that it is very rare for a subsidence problem to be unsolvable, but it sounds like the probability is not that small, from what you are saying.
    – DevShark
    Aug 22, 2016 at 20:12

1 Answer 1


The very likely outcome will be that the structural engineer will go away to do the necessary calculations, specify the requirement for the underpinning to be carried out by a contractor, and the tree will be converted to firewood (tree preservation order permitting).

The underpinning will be carried out and leave the building stronger than it was before. Any additional remedial work (eg to the cracks) will be carried out. Over time (once the repairs have weathered), you probably won't even be able to tell that the work was done.

The problem has been identified before the worst case has happened (crater), so now it can be fixed to mark sure that it doesn't happen.

Without a thorough assessment by a qualified individual (or company), I can't say for absolute certain, but I'd say it is very, very likely that a satisfactory solution to remedy the subsidence will be found.

  • Thanks a lot John for your answer. One of my concerns is how slow our freeholding company will be in asking for the work to be carried out. How long would you say you think is reasonable to wait in this type of cases? Do you think waiting 6 months is reasonable? 1 year? Or too long? (of course you can;t answer in my specific case, but would like your general thoughts). Thanks!
    – DevShark
    Aug 23, 2016 at 8:00
  • 1
    As you suggest, it's hard to say. How big are the cracks? How quickly have they appeared? The urgency of the subsidence will likely depend on how fast it has come on - it can be something that is very gradual over many years. I'd suggest however, that the freeholding company will address it in a sufficiently timely manner, as if they were to drag their feet now that the problem has been identified, they (or they company's liability insurers) would be liable for any further damage caused. In your situation, I'd first be tempted to write to them and ask for their proposed timetable to remediate.
    – John
    Aug 23, 2016 at 14:14

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