Almost any mildewicide will do the trick. Grout sealants all seem to work but I would go specifically to a tile shop to see what they recommend. I think most sealers will work but application and pr ... read more
+1 to the previous comments. Depends on what the foam manufacturer specifies as well as what the exterior sheathing is going to be. I would also recommend a thicker foam for additional insulation and ... read more