Walls – Anatothe of a concrete wall – what are all these layers called

concreteplasterwalls

So my partner and I are trying to resurface a concrete wall in an old house in Taiwan. Before I get into the nitty gritty of asking how, I just want to clarify my terminology first – I think I've got plaster and some other things confused.

This is what the room looked like after she and I finished scraping off all the loose material we could yesterday afternoon.

I used to think the top layer was plaster, but after watching some videos on YouTube, I'm beginning to think the plaster is the cracked, gray layer underneath, and the concrete is just below that. (I'm also hearing that ‘stucco’ is an alternative term for plaster, and that it's called ‘mud’ when wet?)

Is that right? If so, what is the (formerly white, powdery) layer on top?

Best Answer

Yep, you got the Plaster right, it's that coin-thick smooth white finish coating. But, that gray nook & cranny stuff looks to be a Cinder Cement, this stuff is quite weak compared to concrete.

If you were scraping off big bulges & partially loose exploded chunks of the gray stuff, then it's definitely Cinder Cement. That's exactly how that stuff reacts to moderate water exposure & freezing. It's not Stucco nor old plaster work's Brown or Scratch Coat.

Just fill in the big voids with most any kind of cement & then re-Plaster over minor cracks & holes while skim coating the whole room in Plaster. If this will be painted, then the Plaster can just be a Drywall Joint Compound. This is the cheapest & plenty durable enough.