Buying house deemed as high risk for subsidence

GDB2222

Olistanding said:

It was a beam that was fitted under an internal wall although that wall has since been removed. Presumably it still serves some purpose in strengthening foundations but isn't under any structural wall

If nothing is sitting on it, it can’t strengthen the foundation.

tooldle

Olistanding said:

tooldle said:

Have a chat with the surveyor. London clay is a risk but, so many many houses are built on areas of London clay. Clay expands and contracts with climate conditions. The trees (depending on size) will potentially taking up large volumes of water and this may cause some additional shrinkage. In wet conditions the trees might be seen as a bonus.
It comes down to balance. An underpin 21 years ago with no issues in the intervening period. The alternative to find a property that isn’t built on clay, and that is quite a task if you are in the South.

Thanks for this.

I did have a chat with the surveyor and he was pretty clear in the point that the property was at a greater risk of subsidence than others in the area. His main rational to this seemed to be the presence of trees close to the property that were on public land and the neighbours land, and the fact it had previously suffered from subsidence. However, I can't find much evidence that previous issue with subsidence a long time ago makes it more likely to happen again and many other properties in the area have trees nearby.  Think I night try and get a second opinion. Other reasons he mentioned were the soil type and shallow foundations but that's the same for most houses in the area.

I guess the other thing is whether we think the stigma around it having had subsidence in the past is likely to impact on what we can sell it for regardless of whether its a continuing issue 

Our first house had a full underpin, prior to our purchase. Our house was impacted by a collapsing culvert in the street. Just one example I realise but, on resale it broke the ceiling price for the street. Some people are frightened by the word subsidence. Others aren’t and many will investigate circumstances . I grew up in Portsmouth, the whole island is on London clay and perhaps familiarity helps.
Whatever you decide, good luck OP.

Olistanding

Thanks, when we were initially told it had been underpinned we had thought it was done fully so were reassured but now it appears the partial underpinning conducted no longer serves a purpose