Polyurethane Injection

Polyurethane injection involves the very high pressure (1500-3200 psi) injection of polyurethane through injection packers hammered into drilled holes in the poured concrete structure.

Typical applications for polyurethane injection are as follows:

• Actively leaking cracks;
• Cracks where the walls are damp or wet;
• Previously repaired cracks that are leaking;
• Cracks >1/8 inch in width;
• Cracks that appear to be full of mud or minerals;
• Cracks caused by corroding reinforcing bars;
• Leaking tie-rod holes;
• Leaking snap rods;
• Leaking I-beam pockets;
• Leaking underground structures;
• Holes in a wall where electrical conduits or gas lines enter;
• Expansion joints;
• Honeycombing;
• Pool bottoms where access is available;
• Seams created by a cold pour;
• Over head concrete structures; and
• Gaps beneath the window frame and the top of the concrete wall cut-out.

From reviewing the typical applications above, it is clear that polyurethane injection is an extremely versatile waterproofing method that can be used to deal with any leak in a poured concrete structure, under all conditions. This versatility is attributable to the characteristics of our polyurethane resins which are:

• Activated polyurethane expands to 5 times it's volume; this is very desirable when filling large cavities or when the size of a cavity is unknown (as in the case of honeycombing);
• The expansive force of polyurethane is significant; consequently, it will fill any and all gaps that it encounters - this is particularly useful when dealing with very porous concrete or when dealing with honeycombing. It will also expand wherever it can; following the path of least resistance, it will fill any and all voids encountered;
• Our polyurethane resins are non-toxic. This makes them suitable for use with potable water systems such as cisterns;
• Polyurethane sets rapidly in the presence of hydrogen. Since hydrogen molecules are present in water (H ₂ O) the presence of water actually increases the reactivity of the polyurethane. This makes it ideal for use when significant leaks, and significant hydrostatic pressure, are encountered;
• Polyurethane resin will not freeze and always remains flexible; this is desirable when the concrete surrounding it expands and contracts due to thermal cycling;
• Polyurethane sets very quickly. This is useful when stopping leaks where significant hydrostatic pressure is involved;
• Polyurethane injections are done using hydraulic hoses which can be used quite easily, even when accessibility to the repair area is limited; and
• We use polyurethane resins of varying viscosities; this gives us the ability to deal with any situation, from hairline cracks to large voids.

Note: Several technical factors need to be taken into account to determine whether a leak should be injected using epoxy or polyurethane. Trust our trained technicians to determine which injection type is most suited to your circumstances.