Water under block & beam - new build

[newbuildnoob]

Hi all,

We are in the middle of a new build and are facing a problem with water under the block and beam. We get water in there (more when it rains, less when not - it seems to slow down to a near stop after a few days). Soil is London clay, void is mostly below ground level (varies across the building).

The site itself sits low relative to the surrounding land (think of a 10 degree triangular cone with building in middle). We have some concrete and paving planned to be installed around about 2/3 of the perimeter with aqua channel/aco drains, but I don't think that'll take care of it fully.

Is there any sensible way to test/see where the water is coming in from? The only idea I could think of was to maybe lift some of the blocks in the block/beam and dig a small hole between the foundations. We can then see if that fills up first when it rains after pumping it all out?

Any ideas/thoughts appreciated.

Thanks!

 

[theprinceofdarkness]

I have dug deep holes in clay and suddenly come across water flow. Sort of like a little pipe (fissure?) in the clay that drips water at a high rate, cupful in 5 minutes. So leave it flowing overnight and you start to get flooding. A temporary cure is to hammer in a suitable wedge, literally turning of the water.
In your case best thing to do is to dig a groove around your construction and the water drain to a lower point. The other cure would be to tank the building.
Frank

 

[newbuildnoob]

Thanks mate - I was thinking along the lines of a land drain, but even this solution with the geotextile fabric & gravel looks like it would have a limited life. Any ideas how long I should expect it to last assuming access points for pressure washing/rodding? Did think about tanking, but not a realistic option for us I'm afraid.

 

[^woody^]

The idea of a suspended floor is that there can be water below it and it not be a problem.