Polyurethane Injection Leak Repair

By now, many homeowners are aware that polyurethane injection is an economical and highly effective repair method used to fix foundation cracks and leaks in basements. On this page we cover what matters most to homeowners.

The usefulness of polyurethane injection

This type of injection (sometimes referred to as urethane injection) is arguably the most common type of injection used for repairing basement leaks and waterstopping generally, due to its versatility. It is used exclusively for stopping leaks in poured concrete foundation walls and structures. When waterstopping is required in subway tunnels and mineshafts, the cracks and rock fissures are injected with polyurethane (also referred to as grout) - so you know this crack repair method works under real-life conditions.

It should be noted that in some instances epoxy crack injection is a better choice to repair foundation cracks; particularly structural foundation cracks. Click on this hyperlink for a comparision of epoxy and polyurethane injection methods for sealing cracks.

How polyurethane injection works

Polyurethane injection typically involves a high pressure (typically 1500-3200 psi) injection of activated polyurethane resin through injection packers hammered into drilled holes into poured concrete basement foundation walls. Like epoxy, the injected resin travels through the entire thickness of the foundation wall (typically 8") and expands and solidifies within the cavity thereby eliminating the cavity and preventing water from leaking into your basement.

Types of leaks fixed by the injection of polyurethane

Actively leaking cracks;

Cracks in wet or damp basement walls;

Previously repaired cracks (internally and/or externally) that are leaking; Note:an epoxy injection is not appropriate for use in repairing a failed crack injection;

Cracks full of mud or mineral deposits;

Cracks caused by corroding reinforcing bars (typically in reinforced concrete slabs);

Leaking forming tie-rod holes;

Leaking forming snap rods;

Leaking I-beam pockets;

Leaking underground structures in general (such as parking garage cracks and seams);

Underground pipe penetrations in a wall to accommodate electrical conduits, gas lines, air conditioning lines and pipes;

Expansion joints;


Pool bottoms (when access is possible);

Seams created by a cold pour;

Overhead concrete structures;

Gaps beneath the window frame and the top of the concrete wall cut-out.