What is on my walls?

[MrAbody]

Hi All,

Need some help on figuring out what material is on my walls as I have no clue on cement products. I have 2 garages on a property I bought in 2019. My larger garage is just plain concrete blocks, nice and easy. My smaller one is concrete blocks as well, but at some point someone thought it would be a good idea to coat the inside in a rough and uneven way with some kind of thinset, stucco, mortar, or concrete. It of course is falling apart at the bottom an other sections. Where it falls apart I can only describe it as the thin upper layer breaks away (almost like a thick paint that is flaking off) leaving what seems to be fine sand behind it. I can rub my hand across it and the sand falls off. Sometimes chunks of it break off.

Take a look at the pictures and let me know if you can identify what it is. Of course the big question is how best to patch it. I realize that its probably best just to knock it all off the walls but I can't invest that kind of time into it now and just want to patch as best I can and paint it as the garage is really mostly used for storage.

Thanks for any advice!

 

[STINEY]

Looks like a cement-based moisture sealant product. These were common before the advent of petroleum based sealants.

We coated the outside and inside of our old farmhouse foundation (fieldstone and soft brick combination) with TamoSeal to give it a uniform look and block the insects' pathway. Its not perfect but a drastic improvement on the old surface.

 

[The Cobbler]

it looks like what used to be called, whitewash . it was calcium and chalk based I think. it was a very inexpensive coating. and dried fairly hard