What kind of thinset mortar to use for installing slate on top of aggregate?
We have a concrete (aggregate) front porch, and I'd like to install slate tiles on top of it. I'd read that you need a special type or mortar(thinset) when adhering stone to a stone substrate. Does anyone know what kind of mortar/thinset I'll need to use for this project?
If you are talking about a concrete with an expossed aggregate surface, any modified thinset will work. It would be better however in my opinion for you to use unmodified thinset but to modify it using your own additive rather than water. For example: Mapei's Kerabond thinset mixed with Mapei's Keralastic additive. There are others.
If your surface is an epoxy-aggregate surface, the old surface should be removed totally.