Clay soil patio cracks (Ed.)

[darth]

Hi all,

I have a slight issue with a patio that I layed a few years ago and was after some advice hopefully someone can help?

Just a bit of context, I layed a Indian sandstone patio in my garden in the summer of 2022 in a new property I purchased. This is the first patio I have laid on an area with clay under soil and I now have a crack running along a few of the slab joints and possible clay heave (sorry if the term is wrong!)where the corner looks to have lifted around 1/4inch.

As far as I am aware I followed the correct steps in regards to ground work (8inch mot etc), the ground where I live is very dry at times. Today I have big areas in the garden with large voids in the grass (2 inch+ gaps). Literally none of the front gardens where I live that have block paving is flat as well, therefore I would assume this is a common pain in the backside for groundwork with homes being on clay?

In regards to fixing the issue, patio looks absolutely fine, we'll apart from the hairline crack that runs around the area that has moved, but what would the advice be to fix the issue? I appreciate some may say rip it up and do it again properly but I am pretty certain in three years time I would have the same issue.


Just a final note I against my better judgement I didnt use sand and cement to point, I was recommended brush in resin, which I hate and wish I never used. Although from ehat I understand its come on a lot in the last few years.


Any help would be much appreciated.


NJ

 

[yorksbuilder]

What is between the 8 inch 'MOT' and the indian sandstone? did you lay each slab onto a full bed of mortar?

 

[darth]

Hi yes, sorry should have been more clear. Laid on full bed of cement (all slabs also primed).

 

[yorksbuilder]

Clay shrinks a lot in dry weather conditions and this can cause all sorts of problems, manifesting itself as cracks in house walls etc. Probably what's happening with your patio

Water around the edges well and even over the top to hydrate the clay a bit and stop it shrinking

 

[darth]

Thanks for the reply. I will give that a try thanks. As for repairs is there anything that can be done bar just repointing?

 

[yorksbuilder]

If it's bad, ie a trip hazard, you'll need to take things up, remove some base and re-lay. If not, you can just repoint for now

 

[noseall]

I now have a crack running along a few of the slab joints and possible clay heave

Have you removed any shrubs or trees recently, near to the patio?

 

[darth]

No removal of shrubs or trees etc. Indo have a laurel bushbthat runs down the garden and is around 2ft from the patio. Maybe this is causing the problem? It looks more like the patio has slightly dropped, not listed though.