Stone Foundations

A stone foundation is usually built with an inner and outer stone and mortar wall. The space between the two walls is filled with rubble. Over the decades that the below grade outside wall is exposed the water and dampness the mortar disintegrates to dust.

Waterproofing a stone foundation

It is never a good idea to do an interior membrane on a stone foundation wall or poured wall. The interior membrane will guard the interior living space from the moisture coming through the porous mortar but the dampness trapped in the wall and mortar will freeze and the mortar can weaken and even crumble over time. The best waterproofing solution is the exterior repair requires excavating along the outside of the leaking wall or structure exposing the wall from the top down to the footing.

Repairing from the Outside – Membranes

This type of repair requires excavating along the outside of the leaking wall from the top down to the footing. A modern 4-inch perforated drain pipe (weeping tile) is installed. After the wall has been cleaned, repaired, and repointed around the stone, an asphalt based rubberized coating is applied then an air gap membrane is applied over that to cover the entire wall. The trench is backfilled with drainage stone. This system will prevent water from being in contact with the wall, and will solve the problem permanently.