Exposed foundations how best to leave?

[Jilly]

My main stable building has 600mm foundations and the hayshed extension has 6m piles (yes, you read that right!). We are on clay. 

 

I want to enlarge the hayshed (but can't apply until we are a dwelling) so have put enough piles in to allow for this. 

 

The architect and builder both suggested a block and beam floor which could take any kind of wall construction. 

 

Will it be ok to leave this exposed for a considerable time? What do I need to be aware of? I've lost faith in the builder and want to change (its a long story). On clay there needs to be a 225mm void. which will fill with water in the winter. How can the be managed? 

[Declan52]

Won't do any harm whatsoever. You might get a bit of mould if puddles form but a quick brush and some bleach and it will be fine.

If you grout the blocks there won't be lots of water get through.

 

[Russell griffiths]

Yes it could sit there for years. 

[Gus Potter]

6 hours ago, Jilly said:

My main stable building has 600mm foundations and the hayshed extension has 6m piles (yes, you read that right!). We are on clay. 

 

I want to enlarge the hayshed (but can't apply until we are a dwelling) so have put enough piles in to allow for this. 

 

The architect and builder both suggested a block and beam floor which could take any kind of wall construction. 

 

Will it be ok to leave this exposed for a considerable time? What do I need to be aware of? I've lost faith in the builder and want to change (its a long story). On clay there needs to be a 225mm void. which will fill with water in the winter. How can the be managed? 

I would hang fire with the beam and block. Leave the piles and ring beam as they are. If you install the beam and block and leave it for a few years then if something starts happening in the void under (water ingress, mould etc) then you'll have to fix it.. that won't be easy and not good for moral. Also, it does limit your options. Practically you may want to run services in the solum space.. planning that far ahead?

 

Maybe get some free draining goetextile membrane (B&Q?) and lay it over what you have. Then infill back up to ground level. Pick an inert infill material that is easy to dig out and recycle... hence the geotextile membrane. This could be a layer of recycled aggregate. Or you could just dump some broken brick, another layer of textile then some decorative aggregate, some plant pots etc so you can use the space while you wait. It may be that you have a gravel drive.. use the same aggregate so you can "top up the drive" once the work is complete.

 

The key really is to provide a layer of material to protect the underbuilding and solum from frost. Gardeners turn over the soil before the winter to let the frost get in and break it up. Same will happen to the soil under the solum if you don't protect it from frost. The concequence will often be that you end up having to dig the material that has softend.