How vulnerable is CMU to water damage or breakdown?

[pa5tabear]

I'm working on a project where we are replacing a pumping system. The walls of the room are made of painted concrete masonry unit. The paint has not protected well against water, however, and water leaks through to the other side of the wall. It has been like this for years.

Luckily my organization now has money to fix things. Should we completely replace the wall? Will CMU degrade from moisture?

We are wondering if just repainting/resealing it would be sufficient. All it supports is the ceiling above it.

 

[Ron]

You should have a local structural or structural materials engineer look at the wall. I've seen a range from complete deterioration with actual masonry loss to the more common heavy efflorescence of the mortar joints. In most instances, the mortar joints are more affected and those can be re-pointed. You can tell a lot by using a screwdriver to scrape or gouge into the masonry. If the screwdriver will gouge the masonry easily, that's not good. For new or good strength masonry, a screwdriver should not be able to gouge material, just make deep scratches. For the mortar joints use lighter pressure or just use your fingernail to check. Usually bad mortar can be gouged by fingernail scratching.