Hoping for some help. We have granite pavers and would like to set it over H4 sleepers for a shaped flowerbed and paved area 8square meters. We’ve ruled out concrete base for pavers as it’s too expensive ,backyard 30mts from road. What glue can we use to attach H4 to pavers and what flexible mortar can we use to reduce movement from H4 and cracking between tiles? Looked at mortarfil and polymeric sand as options for flexi mortar.