Mission Bay Residence
Internal Waterproofing

Not every waterproofing problem can be solved from outside the building, and a Mission Bay residence where moisture was coming through the walls and floor was a clear example. External excavation around the property was not practical, which meant the fix had to be built entirely from within the affected rooms, and that called for a more exacting process than simply coating over the damp patches.

BlastOff prep ground all of the existing coatings from the walls and floor using HEPA filter vacuum extraction to control dust while exposing the bare substrate underneath. Every crack found across the walls and floor was then repaired with cement epoxy before any membrane went on, since a waterproofing system applied over an unrepaired crack is only ever as good as the crack beneath it. Four coats of waterproofing membrane were built up across the walls and floor to create one continuous barrier, with particular care taken at the junctions between the two surfaces, which is typically where an internal system is most likely to be let down.

For homeowners in similarly tight or built-up sites where digging up the exterior simply is not realistic, whether due to neighbouring boundaries, decks or established landscaping, this project shows what a properly built internal system looks like. A good scoping conversation should cover the condition of the substrate once coatings are removed, how many coats the membrane build-up genuinely needs, and how the junctions between walls and floor will be detailed. Dust control is worth raising early too, particularly in occupied homes, since controlled extraction allows proper preparation without leaving the rest of the house full of dust.

Once finished, the treated rooms at this property were left dry, sealed and ready for finishing, the result of internal waterproofing done properly rather than a quick coat applied over the problem.