Opening jobs continue … appreciate some advjce
Photo shows coping stone above and fibreglass steps below. The mortar in the middle is falling out and I want to repoint it.
What sort of mix should I use?
Seems too light for normal sand/cement , and I wonder if something flexible might suit better due to movement of the GRP.. any pointers?

Photo shows coping stone above and fibreglass steps below. The mortar in the middle is falling out and I want to repoint it.
What sort of mix should I use?
Seems too light for normal sand/cement , and I wonder if something flexible might suit better due to movement of the GRP.. any pointers?
