laitance
/ˈleɪtəns/
noun
- A thin, milky layer of weak cement and fine particles that forms on the surface of fresh concrete as it dries, often making it weaker or preventing a good bond with additional layers.
- The builder explained that laitance can weaken the concrete if it is not cleaned off.
- The contractor had to remove the laitance before applying the new layer of concrete.
- If you don't brush off the laitance, the floor coating may peel away later.