How does polyurethane curtain grouting work?

Curtain grouting is a technique used by contractors to combat expansive water intrusion, such as leaks covering a wide area or through porous surfaces, where traditional crack injection may not be feasible. This method involves injecting a polyurethane resin into the soil immediately behind the leaking structure, creating a watertight barrier or “curtain” on the exterior face of the wall. By stopping the water before it even reaches the structure, this process is highly effective for large-scale waterproofing and is especially useful for sealing active leaks in subterranean areas.

Application

• Step 1 – Drill Holes: Injection holes are drilled in a diamond grid pattern to cover the desired area of the structure.

• Step 2 – Injection Start: Grout injection begins at the bottom of the wall to ensure a complete seal from the ground up.

• Step 3 – Lapping Effect: Grout is then injected a little higher, so that any excess grout flows down over the previous injection area, creating a lapping effect like shingles on a roof.

• Step 4 – Complete Injection: Injection continues to the top of the wall until the entire curtain is formed.

Benefits

• Creates an External Waterproofing Barrier: Curtain grouting injects resin into the soil behind the structure, forming a flexible, impermeable “curtain” on the exterior face of the wall that stops water before it reaches the concrete.

• Minimal Interior Disruption: The repair work is performed through small holes drilled from the interior, which avoids expensive, disruptive exterior excavation and damage to landscaping.

• Addresses Large-Scale and Diffuse Leaks: This technique is ideal for widespread water intrusion, such as leaks through honeycomb concrete or porous soil, where simply injecting a single crack is insufficient.