[NorthJersey]

As I started to strip paint with my pressure washer the other day. I noticed that under the paint, I seem to have two skim coat layers on the block; at least the white stuff in the picture feels abrasive like mortar and it crumbles like a masonry product. Is stripping the paint alone sufficient to achieve an acceptable bond? Should I try to strip away the white stuff before I apply the cultured stone veneer? Should I try to strip away both layers of mortar to expose the concrete block?

 

[bob22]

I would think that anything loose will need to come off; the mortar won't stick for long to a failing substrate.

 

[CplDevilDog]

Not sure how long Surface Bonding Cement has been around but I think this is something people are going to have to start thinking about before stripping mortar and other finishes from block.

I guess a mortar joint between each block would be the quickest way to tell if you are dealing with a traditionally built wall or these new Quikwall drystack versions.

If it is SBC (unlikely but becoming more common) you definitely don't want to remove it, as it is structurally significant.

 

[NorthJersey]

This isn't surface bonded block. That thin layer of white mortar stuff only came off when I used a 3500 PSI 4 GPM pressure washer with the nozzle pressed right up to the surface. I'm thinking all I'll need to do is remove the paint and adhere the veneer directly to the white stuff (no lath).

 

[NorthJersey]

This is from the installation guide from GAF for their CanyonRock manufactured stone veneer: