# Cinder block and joint compound



## mark sr (Jun 13, 2017)

Ideally you would have plastered or stucco'd the block prior to applying any coating. Regular ready mix joint compound [bucket or box] is water soluble so if any moisture came thru the block it would dissolve the j/c making it weak and/or fall off. I suppose you could use a setting compound [Durabond or EasySand] as they aren't water soluble but I don't recall ever having seen anyone use any type of joint compound to smooth out a block wall.


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## ClarenceBauer (Mar 4, 2005)

First you need to address the dry-lock if you rub your hand over it does it leave dust on your hand?
If no chalking than you can use cement plaster over the block.
Before you apply the stucco you should water proof the block walls.
The water proofing material should be compatible with the plaster material used used also it should be breathable.
Make sure the water proofing states that Plaster / Stucco can be applied over it.
Some water proofing materials could be troweled smooth no plastering required.
A good plaster job requires NO sanding also cement plaster is very hard to sand smooth.
Do not use a Gypsum product / Joint Compound if moisture maybe a problem.


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## rkovelman (Oct 8, 2016)

Is cement plaster paintable?


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## mark sr (Jun 13, 2017)

Yes, it does need to cure first. 3-30 days, depending on who you ask.


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