DIY Doctor UK DIY Forums

I am planning to spread a thin layer or mortar over a tarmac driveway then cover it with gravel. The mortar is intended to secure the bottom layer of the gravel to the tarmac surface. I was thinking of using Sika Bond SBR+ to improve the adhesion between the mortar and the tarmac. Would this be suitable? If so, what would be the best way to apply it - add it to the the sand & cement during mixing, or paint it onto the driveway before spreading on the mortar?
Many thanks for any advice.

Hi ash,
Your proposed coating tarmac with mortar will not be long lasting. When the surface gets hot the tarmac will soften leaving the mortar without stable support and it will break up.
Regards S