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Foundations not deep enough to build 2nd storey on top.

I am buying a 3 bed semi. I have now been told that the foundations are not deep enough for a second storey to be built on top of what used to be the garage (now converted to a study room) is it possible to underpin the second storey as opposed to demolishing the whole thing and starting again? Thanks in advance!

3 Answers from MyBuilder Extension Builders

Best Answer

Hi. To be honest, underpinning is expensive & messy. Also, if the existing room is a garage, it might only be a single brick wall rather than a cavity wall, in which case you would need to form a cavity wall somehow to the first floor, and there's nothing to build off of even if the foundations were suitable. In my experience, by the time you have attempted to upgrade the existing structure, it is usually best to demolish & start again, it will be cheaper & easier. Hope this helps, Simon.


Answered 11th Feb 2019

You would be able to use a steel frame to support the upper floor and have less disruption to lower floors, its still messy.


Answered 11th Feb 2019

Is there access to the foundation to underpin? if the access is good and the building inspector is just looking for the standard meter underpin then you are looking at £1,000 pound an underpin, if it not great then you could say up to £1,600 per pin.
Get quotes for both it could well be that underpinning works out to be cheaper than starting again.


Answered 12th Feb 2019

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