Northcote Residence
Below-Ground Waterproofing

Northcote Residence

LOCATION

Northcote, Auckland

SERVICE

Exterior Below-Ground Waterproofing

The Challenge

Persistent below-ground moisture was entering the Northcote home from outside the foundation. Previous attempts to manage the problem with internal patch coatings had proven ineffective, since the water source lay outside the wall and internal treatments could not intercept it before it reached the structure. An exterior solution was needed to address the moisture at the point it was entering rather than after it had already passed through.

Our Approach

BlastOff hand excavated to the foundation to expose the affected walls, then primed the surface before torch-applying a waterproof membrane from footing level upward. A protective layer was installed over the membrane to prevent damage during backfilling, and NOVAFLO drainage coil was connected to the stormwater system to remove groundwater from around the foundation. The excavation was then backfilled with clean scoria to keep the area free-draining and reduce ongoing pressure against the new membrane.

The Outcome

Water pressure was removed from the foundation walls of the Northcote residence, leaving the lower rooms dry. The homeowner received a waterproofing system addressing the source of the moisture from outside the building, replacing the internal patch coatings that had previously failed to keep the property dry.

Intercepting Water Before It Ever Reaches a Northcote Home's Foundation

Internal patch coatings can only do so much when the moisture problem originates outside the building, and that was exactly the situation facing a homeowner in Northcote, where persistent below-ground dampness kept returning no matter how the interior was treated. With the water source sitting outside the foundation wall, no amount of internal patching was ever going to intercept it before it reached the structure.

BlastOff hand excavated to the foundation to expose the affected area, primed the surface, then torch-applied a waterproof membrane running from footing level upward to give full coverage of the wall. A protective layer went over the membrane to guard it during backfilling, NOVAFLO drainage coil was connected to the stormwater system to draw groundwater away from the foundation, and the excavation was backfilled with clean scoria so the area stays free-draining going forward. Together, the membrane and drainage do two different jobs: one blocks water directly, the other relieves the pressure that would otherwise keep pushing against it. That combination is often what separates a lasting fix from a repeat callout.

Homeowners dealing with damp lower rooms, salt staining on foundation walls or coatings that keep failing despite repeated touch-ups should treat those signs as evidence the moisture is coming from outside, not from within the room itself. A proper scoping visit should look at the ground conditions around the foundation, the practicality of excavation, and whether drainage needs to be part of the solution. It is worth remembering that internal treatments, however well applied, cannot change what is happening on the other side of the wall, so a history of repeated internal repairs without lasting results is often the clearest indicator that the real fix needs to start outside.

This project shows why exterior below-ground waterproofing so often outperforms internal repairs for problems like this, since it deals with water before it ever gets near the living space.