How to build a masonry foundation or retaining wall?

Building foundation and retaining walls in masonry must follow the Quebec Construction Code:

Concrete block foundations:

• Standard concrete blocks (CMU) are 200 × 200 × 400 mm, with a minimum strength of 15 MPa
• Foundation walls must be vertically reinforced (steel rods #4 or #5 every 1.2 meters max) and horizontally (mesh in mortar joints every 400 mm max)
• Cavity filling (grouting): cells containing steel rods must be filled with fast-setting concrete (grout)
• Exterior waterproofing (bituminous membrane or waterproof coating) is mandatory, along with a French drain at the wall base

Retaining walls:

• Maximum height without an engineer: 1.2 meters (beyond that, an engineer's calculation is required)
• The wall must be inclined toward the slope (batter) by at least 1%
• Weep holes are required every 1.2 meters at the wall base
• A perforated drain pipe at the base, behind the wall, evacuates accumulated water

Recommended mortar: Type S for foundations (high strength, good adhesion).