Sub base movement - Base movement

[Frazer22]

I am in the middle of prepping a 100mm type 1 sub base for 25m2 patio of Indian sandstone slabs. The ground beneath the sub base is thick, heavy wet clay. One section of about 2m2 moves and squishes upon walking on the compacted type 1 base. Not to a serious degree but there is movement.

Is this a major problem or will the 30mm bedding mix and slabs counter the slight movement of the type 1? Should I raise the height of the sub base further or dig more of the sub grade clay out and replace with more hardcore??

Thanks, fraz

[rxbren]

will cause you issues dig up the type 1 in that section put it to the side and dig down till the spongy bit is gone and fill and compact with stone

[Frazer22]

Thanks for quick reply rxbren