Before photo of the stairs. De-icing salts and high humidity in the cavity below the stairs had deteriorated the treads from all sides. .A before photo.Stone was sourced from an unused staircase of the same building
Boasting the surface of the tread to provide traction and to mimic the original design.The treads are designed with a 3 degree slope and a raised bed, which prevents water from pooling around the mortar joints.A suspended concrete slab was poured on the existing foundation walls. Brick walls were built on the slab to support the treads at multiple locations. The exposure of the soft sandstone stairs to water saturation and frost made mortar selection a challenge. I chose to use a hot lime mix, which is highly breathable and flexible, and added a pozzolan and linseed oil to decrease water absorption and increase the curing speed.
Fundy Stonecraft 