Below-Grade Waterproofing Niagara Falls

Step 1, Harrowgate plans below-grade waterproofing by pour and excavation sequence. We install each concealed section, inspect it before reinforcement or backfill, carry joints and penetrations through designed details, and preserve clear tie-in zones so later walls, slabs, and podium membranes connect without improvisation.

Step 2, Waterproofing coordination drawings. We map all horizontal and vertical membranes, shoring interfaces, mud slabs, footings, pile caps, slab steps, pits, sumps, joints, sleeves, tiebacks, anchors, and upper terminations. Pour breaks and access dictate installation sequence. Drawings identify hold points and leave protected tails for future tie-ins.

Step 3, Blindside and pre-applied work. Against shoring or property-line walls, a stable substrate board is installed over irregular lagging or shotcrete. Pre-applied membrane sheets are lapped, rolled, and detailed around tiebacks and penetrations before reinforcement. Protection from rebar, form ties, welding debris, and foot traffic continues until concrete encloses the membrane.

Step 4, Underslab membrane. Mud slab or compacted substrate is made smooth and dry enough for the selected system. Sheets or fluid material are installed beneath footings, slab, pile caps, and pits, with reinforced corners and watertight penetrations. Reinforcing chairs use approved protection so concentrated loads do not puncture the membrane.

Step 5, Waterstops and construction joints. PVC, rubber, hydrophilic, metal, or injectable waterstop is installed at construction and movement joints under the design. Splices are completed with the approved method, intersections are prefabricated or carefully formed, and profiles are secured against displacement during placing. Joint details connect to the field membrane.

Step 6, Post-applied walls and tie-ins. After forms are stripped, ties, honeycombs, fins, and cracks are repaired. Liquid or sheet membrane is installed from lower protected tails to the designed upper termination. Outside corners, slab edges, sleeves, expansion joints, and changes in substrate receive reinforced detailing before the field layer.

Step 7, Protection, drainage, and inspection. Completed membrane is reviewed before drainage composite, protection board, insulation, or backfill. Flood, spark, vacuum, visual, adhesion, or other integrity testing is used where specified and suitable for the system. Defects are repaired and retested. Backfill and subsequent construction follow a protection plan.

Step 8, Waterproofing records are organized by grid line, elevation, slab zone, and pour. Photos show waterstops, laps, penetrations, tiebacks, injection ports, terminations, and repairs before concealment. Harrowgate maintains a deficiency map through construction and closes each item before cover, because access after concrete or backfill can require major excavation.