subsidence

[s.herbet]

Hello. I'm asking this question on behalf of someone else so don't have many details. The property concerned is late Victorian with a large extension that was built between the wars. This extension has been shifting due to subsidence. I've heard that subsidence can settle of its own accord. Can somebody like a structural engineer tell if this is going to happen or will they always recommend underpinning?

Thanks.

 

[skier-hughes]

A good one should be able to identify if the movement is recent, then they may engage in tests to see if it is still current, but this can take some time.

 

[Lime]

There are many ways ground movement can affect a building and a lot depends on the type of ground the building is on.
Sand or clay are two types there are many more.
A ground inspection together with a careful examination of whatever movement show on the two buildings will determine what to do next, if anything.
If the ground movement and settlement of the building is still happening an engineer will not be able to say with any certainty when or if it will stop.
If the movement is old then nothing needs to be done.

 

[Penners]

I think your friend would be well advised to engage the services of a structural engineer. As Lime has said above, there can be many causes of subsidence - if indeed the problem is subsidence. Heave (the opposite of subsidence) can also cause movement in buildings.

Only an expert on the spot can properly investigate the cause of your friend's problem and recommend a solution. The engineer may suggest underpinning, or some other solution - or no solution at all if none is required.

If active subsidence/heave does turn out to be the problem, then I presume your friend has building insurance against this? If so, then there's a good chance that the insurer will pay for remedial work, including the services of the structural engineer (less any excess specified on the policy).

If this is the case, then I suggest your friend should talk to his/her insurer before calling in a structural engineer, just to to get their OK on the expense.

 

[s.herbet]

Thanks for all the replies. I have just found out they did get an engineer in to do a survey and that they did recommend underpinning. (The subsidence is still happening.)

I hope they contacted the insurance company first but I'm not sure since they are worried about costs.

 

[middi]

If the " shift " is at an alarming rate I would leave until it becomes totally detached then sell it. :wink:

 

[Penners]

Middi - you chose the wrong profession. With a mind like that you should have been a City trader!

 

[Pford75]

Also worth considering what changes may have occurred just prior to the movement. It would be fairly unusual to have a structure without movement for 50 years and then have it suddenly shift enourmously.

Have they undertaken any groundworks, alterations within the house, removal of trees, planting of trees?

 

[s.herbet]

Hi - yes, they did quite a lot of alterations inside the house in 2002 but I don't know whether all the movement dates from then - it could have been from before. I'm not sure what they are planning to do now.