Underpinning - typical cost?

[Kal Ico]

Can anyone tell me roughly how much underpinning can cost please? It is a bog-standard brick 1930's house, 3-bed detached. The previous owners told me that it had been 'monitored' but nothing was found. A couple of the walls are a little out of true, but not massively so. Plus there are no significant signs of cracking (though it looks to have been pointed in the last 10 years). The area has other houses with significantly more obvious signs of subsidence (clay soil).

The valuation report said that there appeared to be signs of historical movement, but nothing on-going, which would be consistent with the off-level floors (very slight, but just noticeable).

I'm getting the property cheap, so can allow for any future cost of under-pinning if not too prohibitive. Alternatively, I could give up and walk away from the deal. TIA.

[SH]

If the current owner has reported the subsidence to his buildings insurance, you can apparently get the get the current insurer to insure you.

I would imagine the premium will be high as if you go elsewhere for buildings insurance.

If you do make a claim for underpinning without taking out a policy wiothe current owner's insurance company, the new insurer won't want to know as it happened pre-inception of the policy and the previous insurer won't be interested as you are NOT their customer.

You mention you had just a valuation? I'd be thinking about having the full survey done.

[Theo]

I'd have thought the surveyor would be able to provide a ballpark price for underpinning, given the situation they find. 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:

Theo

[Jeff Layman]

It's not so much the premium which is loaded for an underpinned property, it's the excess. The bungalow I live in was underpinned in

95/96. The buildings premium I pay is actually less than I paid for our previous house. However, any repairs for subsidence/heave is subject to a £2500 excess.

Note also that it can be difficult to find a new insurer who will quote for an underpinned property. When we moved in over eight years ago the previous owner notified her insurance company that the property was being sold, and we would be taking over the policy. After hearing nothing from that insurance company (who had assured the previous owner we could take over the policy), they changed their minds and said that although the property hadn't changed, the owner had, and they weren't going to continue with the insurance! It took some searching on the internet and phoning around to finally get someone who could give us a quote. For a week we had no insurance on the building, which was quite a worry.

[Jeff Layman]

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.

[Andy Burns]

Back in the 70's we lived upstairs while underpinning was done by pumping concrete under the floors (part estate was built on land that hadn't been drained/filled properly).

[Jeff Layman]

Living upstairs in a bungalow isn't really an option! :-)

From the full info we have on the underpinning and what the previous owner told us, the work took the best part of 6 months to complete. All load-bearing walls - external and internal - were underpinned. That required removing floorboards, and sorting out pipes and drainage. Redecorating was also required where necessary. Not only were the footings reinforced/replaced, but as part of the stabilisation process all around the outside walls are concrete rafts, 2 - 3 metres long, 80 cm wide, and about 12 cm thick. The previous owner said that in total (including living in temporary accommodation) the cost was £60K!

When we had the survey done, the surveyor said that if one property in the road was not going to move it was this one.

One other point of interest is that when we had a conservatory built (60 cm brick walls with cavity), both the architect and structural engineer recommended footings which matched those used for the underpinning. This added a considerable expense (the footings are almost 2m deep!), but they said that this would mean that if there was any movement, the conservatory would move with the bungalow, and wouldn't come away from its walls. With the extreme droughts we seem to be getting now, and with a neighbour's house showing signs of subsidence, I'm satisfied we made the right decision.

[The Natural Philosopher]

I cant remember if its £1000/meter or £3000/metre. I think back in the day when my niece bought a doctors surgery that's what she paid. £1000, but wages have gone up.

Its a quite precisely calculated cost. I'd say if you can afford £3k/metre, buy the place.

A short chat with a structural engineering firm should net you a more up to date figure, and I would absolutely have them involved in the job, because the sort of paperwork they produce will be loved by estate agents and insurance companies both.

[The Natural Philosopher]

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

[Brian Gaff (Sofa]

Yes in this road we are on the top of a hill and pretty immune but elsewhere on the sloping ground there have been problems with this, since its clay and used to have quarries nearby which wer filled in. The whole problem was made worse by an obviously concave load bearing garden wall of stout construction was breached and the soil dug out to make a hard standing for the owners car. I noticed within 6 months cracking on the steps down to the hard standing and I do honestly wonder if anyone actually thinks before they do thing s these days. Brian

[RJH]

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.

[George Miles]

Some floors in my house are very slopey, some walls had a lot more foundations than others, but I guess most of the sinking happened in the first few decades, doesnt appear to be moving any more, so I'm leaving it as a 'feature'

[g]

[alan_m]

You, or future owners, may have problems getting a mortgage so you may also have to factor the cost of selling cheap at a later date, especially if neighbouring properties are showing obvious signs of subsidence.

[Andrew]

I'd guess this mucked up his tv aerial alignment too -