We are renovating a 10 year old house in the Cayman Islands, and a lot of the local customs don’t align with best practices in my experience.

This house is built from concrete filled CMU with the base coat and finish coat portions of an EIFS system applied to the outside. There is no insulation, and no waterproofing was used on the block. I’m told by local contractors that this coating serves as waterproofing, but this contradicts the manufacturer guidance.

A few windows leak, and the house has mold between the drywall and block wall.  We are going to remove this, treat the mold, and reset the windows.

It seems to me that condensation would always be an issue in the wall cavity, with the inside of the housing being air conditioned while the block wall is warmed by the sun.

Adding external foam would increase the cost of this reno quite a bit, but I don’t want to do this work and have the same issues pop up again.