Leaving foundation open time?

[Bob a job]

Hi All,

I am doing a self build extension however I have got to the point I need to dig the foundation, as this is a ring beam on already set piles it may take me a week or 2 to get to the point concrete.

Foundation will be 1 metre x 500 due to needing heave protection with a 450 ring beam. Ground is soft clay.

If I shutter the foundation with 11mm osb will this be safe for say 3 weeks if delays occur? There is a single storey building 3.5 metres away.

Thanks in advance!

 

[r896neo]

It will only have practical implications, most notably that it will collapse here and there and need cleaned up and dug back out before filling. at 1m deep its not going to be anything large falling in but shuttering will stop most of it. weather will have a big effect on the amount and severity.

Also obviously it will fill with water which may need bailing or pumping out so leave a small bucket sized sump in the lowest corner to aid this process.

 

[noseall]

Our take on it is get the trenches filled as quickly as possible. Just dig them out closer to the time that you will be ready to fill them.

 

[bernardgreen]

Our take on it is get the trenches filled as quickly as possible.

Mine as well. Dug a 4ft by 8ft by 4 foot deep hole ( foundation for a chimney stack ) and left it with shuttering for a week and found it half full of mud when we came to fill it.