Good News, Bad News

[timo]

The Good - No frost heave this winter. The dome is still strong and perfectly together. No major cracks and its ready to be fired.

The Bad - My entire stucco job on the outside block walls totally came off due to moisture. Take a look:

I chipped the perlcrete back to the dome to reveal the hearth slab and chipped off the remaining stucco on the walls. I am thinking the horizontal surface caught the water and funneled it down the perlcrete layer, then went between the stucco.

I am thinking of building up the flat areas and sloping away from the hearth perlcrete based.

Looking for any insight into sealing the block walls. What can I put on these walls so I know it won't come off?

Timo

[kebwi]

What kind of stucco did you use?

[timo]

It was mixed at home. Looking back I probably didn't put enough sand in the mix. I used the 1/2 portland 1/2 lime masonry mortar and sand. I used acrylic additive and reinforced mortar for the dome and it weathered pretty well. Would it help to put something onto the block for the mortar to stick to something?

[michelevit]

i'd take an angle grinder with a diamond blade and cut some horizontal grooves into the slab.
The grooves will give something the stucco to bite into.