This Frenchs Forest homeowner was dealing with damage on both sides of the house — and it wasn’t cosmetic. Inside, paint was flaking and the brickwork had turned powdery to the touch. Outside, the render was cracking and pulling away from the wall.

Two different symptoms. Same cause.

When rising damp affects both internal and external surfaces, the moisture has saturated the full width of the wall. The masonry is acting like a sponge — pulling moisture up from the ground on both sides and depositing salts wherever evaporation occurs. Inside, the salts attack the paint and the brick face. Outside, they force render away from the substrate.

Frenchs Forest homes of this era — predominantly 1960s and 1970s double-brick — were built with basic damp-proof courses that were standard for the time but were never designed to last 50 years. The surrounding bushland retains moisture in the soil, and the clay beneath these properties swells and contracts with the seasons, keeping the moisture cycle constant year after year.

The internal damage — powdery brickwork — told the worst part of the story. The salts had penetrated the brick face itself, not just the mortar. That’s beyond a repaint. The bricks were being destroyed from within.

Both internal and external walls were treated. Small holes were drilled at close intervals along the base of each affected wall, and DampBlock™ — a silicone-based cream — was injected into the mortar course. The cream cures to form a continuous waterproof barrier within the wall, cutting off the moisture path from the ground on both sides.

Once the DPC was in place, the damaged surfaces were addressed. Salt-contaminated render and degraded plaster were stripped back. A SaltBlock™ salt-retardant base coat was applied to prevent residual salts from bleeding through, followed by a breathable finish that lets any remaining moisture escape while the barrier takes full effect.

The DampBlock™ injection and SaltBlock™ treatment were completed across both internal and external walls within two days.

The damage that appeared to be two separate problems — flaking paint inside and cracking render outside — turned out to be one. Moisture rising through the full width of the wall, attacking every surface it could reach. With the new DPC in place, the salt cycle was broken on both sides.

No brickwork removed. No excavation. No membrane. Every DampBlock™ treatment is backed by a 20-year warranty. Seeing damp on both sides of your walls? A free assessment maps the moisture and explains what damp proofing can do.