Saturated sub-base

[jondaw]

Hi,

Looking for advice. I recently dug out and add sub-base for a circular patio. Then had loads of heavy rain over a couple of weeks. A few dry days followed and I used a plate compactor. Two thirds has packed nicely, but the remainder moves underfoot, presumably due to saturation as water also rose to the surface during compaction.

I’m worried about now laying the sandstone flags in mortar as suspect there could be movement underneath. Any suggestions to get around this so I can lay the flags, or do I simply need to wait for it to dry out (probably next summer)?!

Thanks,
Jon

[dig dug dan]

Did you put a membrane between sub base and sub grade?

[Bob_A]

Like yourself I'm on here to learn but I did notice this the other day. I wonder if it might help?
Digging a sump

[jondaw]

Hi Dan,

Yes, I did.

Bob - thanks for pointing me toward that post - really helpful. Off to dig a hole...

Cheers,
Jon

[Dave_L]

If you've got a spongy sub base, you'll either need to let it dry out and firm up (which it will do) or re-excavate and replace.

Whats a problem today won't be a problem in the future if you do the correct thing now......all depending upon your timescale.