Building Inspector says soil too soft?

[Tigger71]

Currently started an extension where we replace old kitchen and conservatory with a kitchen/diner. footprint is no bigger than old conservatory and the plan was to use existing foundations for conservatory and build up on.

Building Inspector came on site today and he wasnt happy. He thinks our soil is too soft ?

What likely options are our builder to come back with? Anyone had similar problems and what did you do?

Current foundations go 1metre down and on paper they would have been enough if it wasnt this issue with the soil.

[meboo]

Yes - I had a similar issue with a building I inspector but it was about the depth of existing foundations not the soil. I can’t remember the exact solution (because I didn’t really care, I just wanted it sorted), but there was one and it cost us about another £1k

I think the options include digging out old foundations and redigging.

[Mr Tom Morrow]

I would have thought the Builder would recommend a wide strip foundation with rebar. That spreads the load bearing capability over a wider area then a traditional strip.

More than double the cost, the rebar is cheap it's the concrete that costs plus extra excavation.

[Tigger71]

Thanks! That gives us some idea

[UncleLatch]

Probably something like this...

[tspill]

It really depends on all sorts of things. depending on the problem, they can widen the strips. Or go deeper. Or reinforced raft. Or piles if it is really bad.

We were lucky with our soil a few weeks back when we dug ours. But our builder was telling us about other places where they had go down the options mentioned above. Mainly digging down to get whet they needed.

Most costings assume a 1m deep strip foundation unless they do a ground test and know what problems they will face. We had a £3K contingency in our costing to cover issues discovered in the ground.

[Tigger71]

Thank you for sharing your experiences. We’ll see what the builder says today.

[Tigger71]

They are going to underpin the existing foundations it seems like which is cheaper than to have to completely replace everything. We had to get our structural engineer back on site and she had to do new drawings which we have now sent to the building inspector and I suppose it is now a matter to try to chase them down to see if this is acceptable.

Fingers crossed !

[tspill]

Originally Posted by Tigger71

They are going to underpin the existing foundations it seems like which is cheaper than to have to completely replace everything. We had to get our structural engineer back on site and she had to do new drawings which we have now sent to the building inspector and I suppose it is now a matter to try to chase them down to see if this is acceptable.

Fingers crossed !

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If the SE says it is OK, then it is OK. Building Inspectors generally just want professional cover which you now have.

[Tigger71]

Building inspector says it looks good on paper but she wants to inspect the base once they have dug out. My builder hd to release his men to other jobs so they will not be able to start again until Weds next week.