On Fri, 14 Jan 2005 23:01:04 +0000, The Natural Philosopher
wrote:

Been looking at a poetntial buy for a friend, and it looks like part of
it - a rather shoddy 70's extension - has a bit of a subsidence problem.
Possibly due to a couple of trees nearby - one a willow.

IF - and pending investigation - it needs underpinning, has anyone any
ball park estimates for costs?

Walking away from the buy is not in the frame really - its more about
price adjustment to reflect the condition.


Relevant information is :-

- access for machinery is no problem
- it's on clay soil, and wettish clay (quite low lying)
- about 20 meters of wall might need treatment.
- my guess is there are minimal foundations - one or two feet at the
very most.

My wet finger guesstimate was a grand a meter absolute tops, thinking
that it could hardly take more than a week for a bloke with a shovel and
a cement mixer to dig out a bit and fill it with concrete. At 10 quid a
day max.

It could be possible to take up the internal floors as well if this is
desirable, but that would be far more of a job.

I am after any information anyone has on techniques that are employed to
do this job, and any real world data that is better than my wet finger
guesstimates.

In fact any information on mild subsidence and its remedy would be welcome.

In my experience underpinning is about having enough balls to dig the
dirt out in the first place, it is a DIY job - but it gave me some
sleeples nights.

I would get a strutrial engineer in, to design the underpinning, and
even dig an exploritry hole at the house before you purchase. This way
you know the costs. If you tell the engineer you want to DIY the job,
he should be able to design a DIYable answer.

Rick