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Groundwork & Foundations

Is is feasible to underpin a single storey single brick extension?

The surveyor has recommeneded exposing the foundations and taking any remidial work required. Eg having an extra internal skin, repointing areas which have cracks etc to stop further movement. He has not mentioned underpinning. Would underpinning the extension prevent further subsidence?
Than you

7 Answers from MyBuilder Groundworkers

Best Answer

Hi,there is a new way of underpining on the market, its done by a few companys by borring a few 20mm holes in the soil down to a depth under you excisiting footing,they then pump expanding foam down a 10mm pipe at high pressure,the foam hardens like concrete in a few days curing your problem,no digging,fraction of cost,do homework on internet for company.

2011-05-24T21:20:01+01:00

Answered 24th May 2011

yes by underpining the property would stop further movement paovideing it done propley and get a structial engineer involved

2011-05-24T18:00:02+01:00

Answered 24th May 2011

He should have mentioned underpinning how ever if he is well experienced I'm sure there may be a reason he hasn't. There would be no point in re pointing as it would probably re occur with out underpinning first. I would recommend exposing the foundations as mentioned then asking a surveyor / building inspector to make an assessment on the existing footings.

If underpinning is done correctly I am sure this would solve your problem and then re pointing would bring the finish of the brick work back to a good standard, however with out seeing the structure for myself it would be hard for me to say for definate.

Hope it helps,

Kind regards

Richard Charidge

2011-05-24T20:25:02+01:00

Answered 24th May 2011

to be perfectly honest with you it would be more feasible to knock down and rebuild ,underpinning is expensive ,and with only a 4 inch structure its not to regs anyway throwing good money after bad in my oppinion ,rip out and dig new to regs and rebuild with cavity wall lot better in the long run
regards mitch
substructure

2011-05-24T20:25:02+01:00

Answered 24th May 2011

Yes and also to mention that the existing foundation would probably only accomodate a single leaf of brickwork and would have to be made wider for the cavity formation, this is in addition to the underpinning.

2011-05-24T20:25:02+01:00

Answered 24th May 2011

Yes absolutely. If done properly! It is the best and only option for subsidence. He should have mentioned underpinning. Adding another skin will only add more weight making it even worse!

2011-05-24T18:00:02+01:00

Answered 24th May 2011

Repointing the wall wont stop further subsidence, you really need a structural engineer to advise you on the under pinning, not a surveyor.
If you are adding another wall, then yes its likely it would need to be underpinned.
As this is structural works, building control will be involved.

2011-05-24T20:25:02+01:00

Answered 24th May 2011

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