Repairing Loose Bluestone
What’s the best way to reinstall 2 pieces of 2’x2’x1″ bluestone that have become loose from the 6″ slab below my patio? Once the mortar is removed and the 2 pieces of bluestone washed clean and dried, do I just stick them down with a good concrete epoxy or use a thin coat of portland mixed with a bonder fortifier?
Understand, I want it done right the first time so I’m not doing this every few years.
Replies
What is the thickness of the mortar under the stone? If it's 1/4" or less, use thinset tile adhesive. If it's more than 1/4", use mason's mortar. Both available in sacks.
David
The mortar thickness is 1/2-3/4" (Bluestone is very uneven), but I don't want to add any height to the 2 loose pieces and I don't believe it's necessary to chip out 4sqft of mortar. Will the standard mortar work using a very thin skim coat (1/16") or should I use some sort of straight portland mix to stick them down?
Steve,
"Understand, I want it done right the first time so I'm not doing this every few years."
I have done many repairs like this at area colleges. The correct way is to remove the old mortar bed.
I generally score the old bed with a diamond blade in a grinder and use a hammer and chisel to chip it out. Then I rough up the back of the stone with the grinder. Make sure you wash it all off good.
I set the stones in portland cement. I usually add a bonding agent to the mix and brush a light coat on the back of the stone and pad. Make sure you point all the stones, push the mortar in good, you don't want any voids. Also check all the other joints for loose or cracked mortar, ignoring them now will cause you more loose stones in the future.
Todd