Grout for exterior tiles
Bill , (WKearney99) is absolutely correct. For some reason many people think that installing tiles is going to make the installation waterproof since tile are used in wet areas. NO! Neither tile or grout is going to stop water from going into the substrate and below.
You need to remove everything until you get to the framing and start there.
Tile 4 You LLC Troy, MI
KERDI Shower Specialist ... DITRA Installs ... Product-Method suitability consultation. I have NEVER made a mistake, I thought I did once...........but I was wrong! - PRODUCTS ADVERTISED WITHIN MY POST ARE NOT ENDORSED BY ME!