Help needed! - Block paving

[Djcatfood]

Advise needed .. I want to extend my driveway. I dug the footings down 200mm put a textile membrane down and 100mm of grade one and whacked it down. The problem is that it’s on wet clay and it’s spongy. What are my options??

[Djcatfood]

I’m going to dig up a section and see how dry it is? if it’s wet is it advisable to add more mot 1 or something larger ie brick rubble underneath?

Any help would be much appreciated

[Djcatfood]

Anyone?

[Bob_A]

In my experience you will get an answer, they are a very helpful lot on here but they are also busy making a living. Sometimes you get an answer straight away, sometimes you have to wait, just the way it goes

[Tony McC]

I do try to check the Brew Cabin every day, but sometimes it's just not possible for all of the reasons Bob mentions and a whole host more!

Brick rubble will do nothing but make matters worse. You need to get the sub-base to dry out.

A properly constructed sub-base will rid itself of excess water, either by draining to ground (assuming the sub-grade is suitably permeable), or via buried land-drainage which provides an escape route from the sub-base to some suitable outfall point for those times when conditions are bad. Once the paving is in place, far less surface water will find its way into the sub-base, so it becomes much less of a problem.

For now, find the lowest point within the sub-base area and dig a sump, which is essentially a deepr hole where all the excess water will collect. From that you either bale out or pump out the excess and get rid. It usually needs around 24-48 hrs without heavy rain for a sodden sub-base to drain and firm-up sufficiently to allow paving to be installed.

[Djcatfood]

Thankyou so much for the detailed reply and sorry for being impatient I can breath now lol.I had a look underneath the membrane and there is a layer of clay silt underneath. And the mot is sodden wet like you said. A friend offered to bring his mini digger over and scrape the mud out and go to 6 inches of grade one instead of 4.Do you think this is a better option or just leave it to dry out. I was going to chuck some lime in too to speed up the process.

[Tony McC]

The 'scraping out' and adding more Type 1 will certainly improve matters, but adding lime will lead you towards disaster. A sub-base is intende to be flexible: lime will stiffen it and reduce its long-term effectiveness, so don't do it!

[Djcatfood]

Thanks tony your a legend!