Chipping up the wall is a variation of an old method that seems to work the best for us. Sand blasting is a real chore and not cheap. Usually, sandblasting leaves a dust cloud that looks like a fire in the distance.
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| Here paint is chipped off using a chipping hammer. A good place to buy these is from Harbor Freight. Deep holes don't matter. They have a better key for the mortar. | A race between a hatchet and an electric chipping hammer shows the hatchet is almost as fast. It is good to have a grinder on the job to sharpen the hatchet or bits once in a while. |
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| Ready for mortar. Chips leave areas both rough and porous
for a permanent
bond. |
Flex con is
used for additional adhesion.
We mixed flex con half and half with water and mixed it into the dry mixed mortar. I have to advertise also for Milestone. Milestone "E" chemical is concentrated and will make the equivalent of 3 buckets of flex con, diluted with water. The acrylic not only is adhesive for a good bond, but is resistant to cracks and adds strength. |
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| Here the dry mix is mixed with the wet mix with a drill, but a hoe works, too. | Scratch coat is applied with a lot of pressure to give a good squish
into the holes. Scratch coat is scored and allowed to set 2 days before
the brown coat. How long will this last? I think about
4,000 years. |
We have had a lot of cracks nailing metal lath over the painted block. I think the reason we have excessive cracking with lath is the paint forms a “slip joint”. The stucco expands and contracts one way and the block or brick another way, causing a lot of cracks. Nailing lath on block is also a slow and expensive process. Even with stub nails or pin set pins the lath doesn't seem to be attached as well as putting the mortar right on the block. Nailing brick is unreliable. The nails break
up the brick, leaving the only resort of driving nails into the mortar joints.
Most of the area of the block is chipped up, leaving the pores open on the blocks for a good bond. A few holes don't hurt, mortar squished into these holes form a good key for the slab. We have had very few or no cracks at all using this method.