Subsidence - clay soil

[Regina1]

Hello,

We have bought a house in 2020 which has an extension from 2008. After noticing more and more cracks in the extension, we engaged our insurance. They have gone to monitor cracks and foundation. They have also conducted a drains survey (fine) and a soil survey (one area definitely far wetter than rest of samples). No tree issues. As I am impatient and worrying after such long wait I am wondering whether underpinning can help a clay soil issue of 'water pockets'? I now worry that nothing can be done. Can someone take my worry away?

 

[George_engineer]

You need to monitor the crack movement for at least 6 months, ideally 12 months.

Underpinning is not usually a good solution if it can be avoided.

 

[Ivor Windybottom]

Has anyone actually looked at the foundations? You need to dig down the side of it, see how deep and wide it is, what it's sitting on and what it's made of, whether it's cracked etc.

Do you have the drawings from when it was built? These may be available from your council's planning website. Don't rely on them though, physically check to see what was built.

 

[SpecialK]

Was the extension signed off by building control?

 

[freddiemercurystwin]

How about some photos?

 

[Ivor Windybottom]

We have bought a house in 2020

As you bought in 2020 you may still have the right to sue the seller if they failed to declare something that was asked by your solicitor.

They should have answered a series of questions, including whether anything built was approved by building control. If they gave a false declaration then you could sue them for the cost of fixing it.

But there are time limits, I don't know if it's 3 or 6 years but if you still have a chance then get your skates on and get on with it. You need to make them aware of the issue before this deadline.

 

[^woody^]

As you bought in 2020 you may still have the right to sue the seller if they failed to declare something that was asked by your solicitor.

They should have answered a series of questions, including whether anything built was approved by building control. If they gave a false declaration then you could sue them for the cost of fixing it.

But there are time limits, I don't know if it's 3 or 6 years but if you still have a chance then get your skates on and get on with it. You need to make them aware of the issue before this deadline.

Lol. There's more chance of me being best man at Freddie's wedding.

 

[Regina1]

You need to monitor the crack movement for at least 6 months, ideally 12 months.

Underpinning is not usually a good solution if it can be avoided.

Thank you for the reply. They are monitoring it and have done lots of investigations. Nothing obvious other than wet soil under foundation in one area of the house.

Why is underpinning not a good idea?

 

[Regina1]

Was the extension signed off by building control?

Yes - foundations are 1.2m. We were convinced that the builders must have been cowboys but every investigation comes back absolutely fine. Drains dude said it looks like they were laid yesterday...

 

[Regina1]

As you bought in 2020 you may still have the right to sue the seller if they failed to declare something that was asked by your solicitor.

They should have answered a series of questions, including whether anything built was approved by building control. If they gave a false declaration then you could sue them for the cost of fixing it.

But there are time limits, I don't know if it's 3 or 6 years but if you still have a chance then get your skates on and get on with it. You need to make them aware of the issue before this deadline.

Thank you but I doubt we'd have any chances there. We, for a long time thought they were settling cracks that appeared in the past 2-3 years - well, builders agreed with us back then. It then became more obvious with doors and windows jamming and funky cracks. We also had a structural survey when we bought the house with no indication of a problem.

 

[Regina1]

Has anyone actually looked at the foundations? You need to dig down the side of it, see how deep and wide it is, what it's sitting on and what it's made of, whether it's cracked etc.

Do you have the drawings from when it was built? These may be available from your council's planning website. Don't rely on them though, physically check to see what was built.

Yes, I should have mentioned that this soil analysis team or whatever they are did in fact check the foundations. 1.2m in the extension. We honestly thought the builders of the extension were cowboys but all investigations come back clear - except the wet soil in one part of the house.

 

[George_engineer]

Thank you for the reply. They are monitoring it and have done lots of investigations. Nothing obvious other than wet soil under foundation in one area of the house.

Why is underpinning not a good idea?

Underpinning is very disruptive to a building and can just move a problem rather than simply solving it.

Unless there is something odd going on with the soil strata (for example, our in Lincolnshire you can get a thin crust of firm soil overlaying soil soils and the 1.2m had penetrated that crust), underpinning is unlikely to help.

Could you post some photographs of the cracking?

 

[SpecialK]

Yes - foundations are 1.2m. We were convinced that the builders must have been cowboys but every investigation comes back absolutely fine. Drains dude said it looks like they were laid yesterday...

In that case we need pictures of the cracks. Are they internal? External? Between new and old? Any idea on the existing house foundations? I assume same as the new extension or less if building control were involved.