Block paving on absolutely soaking clay

[Barry]

We are currently laying a small area (30 or so metres) of block paving in front of a shop.

Having dug out to 250mm, it had been our intention to follow our normal procedure of putting down a thin hardcore bed, 125mm of scalpings, 60mm of sand and then 60mm blocks. All, of course, compacted with the heaviest roller we have.

But, what with the weather of the last few weeks, the soil - a heavy clay - is absolutely saturated. The drive will be used for parking light vehicles (probably cars only).

Should we leave everything to dry out before putting down the sub-base, or am I worrying too much ? Does anybody have any other comments ?

Thanks,

Barry.

[84-1093879891]

Hi Barry,

sounds like a job that could use either a short length of land drain beneath the sub base or a drainage composite. I'd definitely consider using a geo-membrane, something like Terram 1000, as that will keep the sub-base separate from all that clay.

Skim off any sloppy clay/mud on the surface, get the geo-membrane down and the sub-base in as fast as poss before the rain returns. Once it's in and compacted, it will help prevent the sub-grade degrading any further and you should have no further trouble - touch chipboard! :)

Why 60mm of sand? Is that before you compact and screed it?

[Barry]

Thanks for your help - it's very much appreciated.

I've ordered a roll of Terram 1000 from Sheffield Insulations down in Tonbridge (they do a "mini-roll" of 4.5m x 11m, which is fine for this job) and will throw it down as soon as I can.

Yes - that is the depth of my sand bed before compaction and screeding.

Thanks again,

Barry.