The Brew Cabin

Posted: **Wed Aug 09, 2017 6:52 pm**

Hi

Just a quick question, how important is it to have 300mm of compacted subgrade as a capping layer above a soakaway which is to sit under a driveway?

Could I get away with less? Say 150mm capping layer and then a further 150mm as planned across the whole drive. Rather than 300mm then 150mm?

I may have dug the hole out a little shallow...

Posted: **Thu Aug 10, 2017 10:52 am**

Compacted sub-grade??? Do you mean compacted sub-BASE?

It's important to have what is, effectively, a load-spreading 'bridge' over a soakaway so that there is no point load applied to the structure. Whether 300mm is necessary is debatable, but it's a reasonable 'average' figure. You might get away with, say, 150mm, and HD applications could well need 600mm, but I really wouldn't skimp on it unless I absolutely had no other choice.

Posted: **Thu Aug 10, 2017 10:06 pm**

when things have been tight,we have used 393 mesh and 150 of concrete and then 150 of type 1
done this twice and it is still there
LLL

The Brew Cabin

Capping layers above soakaway