On 2 May 2021 at 09:49:50 BST, "The Natural Philosopher"
wrote:

On 02/05/2021 08:44, Jeff Layman wrote:
On 01/05/2021 23:52, Theo wrote:
SH wrote:
You mention you had just a valuation? I'd be thinking about having the
full survey done.

I'd have thought the surveyor would be able to provide a ballpark
price for
underpinning, given the situation they find.Â* That would likely be more
accurate than any random number we might generate.

If there's anything dubious about the structure then a proper survey
would
be worth its weight in gold, I'd have thought.

FYI, for what little they're worth:
https://job-prices.co.uk/underpinning-house/
https://www.myjobquote.co.uk/costs/underpinning-a-house

Although it probably won't affect the OP, another cost which might have
to be added is that of hotel/renting if the house owner has to move out
while the underpinning work is being done.

I doubt that would be necessary

All it is is carefully trench alongside the property a very small
section at a time to prevent collapsing, digging under what foundations
there are - if any - and filling the hole with concrete.

Mostly by hand

That's how a guy explained it to me when I had a quote for a cellar
conversion, and the need for an additional metre under the footings (or
whatever counts for a foundation in my house). He quoted £20,000 for a basic
c.10m x 5m room with tanking.

The key, or his USP as he would have it, is excavating without disturbing the
occupants upstairs. He had a conveyor belt thing and a plan.

--
Cheers, Rob