Bonding a new color coat.

I am getting prepared to stucco my 1969 block ranch home in the Phoenix area. My husband wants a Santa Barbara finish. I’m starting to meet with different contractors. I have two small questions:.

1. Why do all the web sites say you shouldn’t fog coat a Santa Barbara finish?

2. Does a bonding agent need to be applied before the color coat on a new stucco job like ours?

Thx !

The reason you can't really fog coat a Santa Barbara finish is the finish is troweled smooth and the pores aren't open. Fog coat coat needs a rough finish like a float finish for the fog coat to soak into the pores.

Re-coating unpainted stucco.

The original house had never been painted. A few patches from moving windows and doors really required a re-coat. The finish coat was white cement and yellow masonry sand.

Bonding coat with an acrylic bonding admixture.

We found that paint on bonding agents don't work very well for recoating. Here, we are using an acrylic bonding admixture in the mortar. We are putting on a thin basecoat first.

Bonding coat using an acrylic bonding basecoat.

The finish coat is white portland cement, lime and white sand. The basecoat makes all the difference over putting a finish on a paint on bonding agent like weld crete. The basecoat has suction, allowing the mortar to take up, meaning become firm enough to work with. Putting finish mortar on a paint on bonding agent is like putting mortar on an ice cube. It just slides around. Also the finish never sets up all the way and you can write your name in the wall with a pencil. In hot, dry weather the mortar will dry up before it sets, turning the mortar into a crumbly powder.

Dry mix of portland cement, lime and sand

Our basecoat: Portland, lime and sand is dry mixed in a box. The dry mix is shoveled into buckets of flexcon and water and mixed with a drill. This sets fast, so care is used not to mix too much.

Mixing dry mix with flex con.

Flexcon is mixed half and half with water. Another benefit of flexcon is you can out it on thin and it won't dry out. Flex retains liquid in the mix.

Bonding mortar to old slick bricks.

Here we are using our flexcon bonding mix on these old slick bricks. The stucco didn't bond well to these bricks on this 1920 foundation and was easily scraped off. It won't come off easy this time.