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Cracked uneven flagstone patio repair

freddal's picture

I have a flagstone patio which was constructed on concrete.  There are two problems. First is the mortar between the flagstone is all cracked and breaking up and second some areas of the concrete slab under the flagstone has settled causing an uneven surface.  To fix this I was thinking of  pulling up some of the flagstone in the area that is uneven and putting either sand , dry mortar, dry cement or polymeric sand under the uneven flagstone.  I going to take out all the cracked cement between the flagstone and use poymeric sand between the flagstones. Will this work?  Should I use mortar, cement or polymeric sand to level the flagstone?

Sounds like a mess. What to (post #215634, reply #1 of 1)

Sounds like a mess.

What to use to fill below the flagstones depends on how far the concrete has sunk. If it's only 1/2" then use Thin set to fill the gap and to set your flagstones in. You can apply a coat of thinset to level the base then set the flags ina very heavy bed of more Thinset. Neither sand or dry cement would make an approprite repair. 

Florida Licensed Building Contractor, 50 years experience in commercial remodeling, new homes, home remodeling and repairs and all types building maintenance.