Bonding stucco to concrete using Acrylic admixturess.

I am designing walls around a tennis court. We may use CMU or cast concrete. What do I need to know about bonding stucco to cast concrete ?

One method of bonding mortar to concrete is a bonding coat made of acrylic and portland cement painted on with a stiff brush or broom, followed by a finish coat. This is frequently done for plastering swimming pools.

Here is my method:

Mix cement mortar with clean sand, not too coarse, with a 50-50 mixture of Flex-con and water.

A good mix for this a mix that is a little rich (less sand, more cement),

1 bag portland

1/4 bag lime

15 -18 shovels of sand.

Trowel mortar on 1/4-1/2" thick on clean concrete.

If the concrete is straight this coat can be evened out with a trowel, and roughed up by rubbing with a rubber float when it starts to set. It also can be roughed up with a brush, but care should be used not to use a brush that is too wet. A wet brush tends to leave the surface powdery when it dries.

The most important thing is to leave the surface rough with open pores to provide a good bond for the finish coat. This is similar to the method that is widely used for plastering swimming pools, but I like my way better.

Stucco over flagstones using an acrylic bonding admizture.

Here, acrylic bonding admixture is used in the scratch coat over these flagstones. Does it work ? I guarantee it.