Footings

This may be the wrong forum site to ask this question but here goes.

We have just started to dig the footings for my new house. In one spot we are having to go down to 2.3m because of a hawthorn hedge !!! (according to our structural engineer) But we have hit what we think (hope ?) is a pocket of waterlogged sandy material. It isn't quite running sand - I have seen that.

Consequently the trench sides are collapsing. Personally I think the best option is to use trench sheeting and shore up the trench while the concrete is poured. We are using clayboard on the house side of the footing and if we used it on the other side as well the sheets would come out O.K. afterwards.

I have no experience of using trench sheets. Is it a job for the experts or can my builders install them ? My own 3CX is on site at all times for retrieval purposes. Could we install them by using the digger to smack them into the bottom of the trench ?

Any info./help would be appreciated.

May be best asking your builder if he's capable or even wants to do it. It isn't a seperate trade installing trench sheets so ask your builder first and then maybe engage a Company experienced in civil engineering projects. Above all consider the safety aspects and if you do it yourself I'd advise getting as much info as you can on this side of it from the web as the Health and Safety officers take no prisoners if anyone is injured.

Thanks for that. Builders have come up with a plan. I'll keep you informed.

O.K. panic over (nearly). The rest of the site was fine and so we dug and poured without too many problems and left the 10 metre troublesome stretch until last.

We divided that into three sections and dug and filled the two end sections with day joins at each end where they will join the middle section. We didn't use any sheeting. just took the hit and fired lots of concrete in. All was inspected by building control AND NHBC.

Tomorrow is crunch day. Dig out the centre section (which was the worst part of the collapse) and put 10 mts in that.

Thanks for all the advice.

I assume you have kept your structural engineer informed of all this..

It was the structural engineer who gave the recommendation as to how we should proceed. We were all surprised that the NHBC decreed that we should solve the problem differently to what the SE had said.