Magk-crack yun pag hindi maganda ang semento, or yung mix mismo ng aggregates. Class AA mix dapat or better (ASTM spec) pag slab.

Anyway, make sure na everything goes down the drain immediately and no pooling of water. Also watch out for water track. Saan ba yan pupunta pag nanjan na.

Elastomeric works as a sealant but you can also use bituminous membrane.

Good luck with your foreman. Nakakatakot yang ginawa mo that you hired an amateur for your own house.