We have two levelling options including the HA5 Self Levelling piece and HS2 slope corrector. Both of these can be used when the surface of the installation is slightly unlevel.
HA5 Self Levelling - Will correct differences upto 5%. Simply pop into the base wherever needed and the top plate clips in. Pack of 50 pieces
For our HS2 - Please see here: https://hardystonecompany.co.uk/product/hs2/
Slope corrector to reduce inclination differences from 2% to 10%. Each section has a 2% correction. Maximum five numbers per riser, giving a 10% difference. Simply clips to the base bottom.