This type of injection (sometimes referred to as urethane injection) is arguably the most common type of injection used for repairing basement leaks and water stops, due to its versatility. It is used exclusively for preventing leaks in poured concrete foundation walls and structures. 

You should note in some instances epoxy crack injection is a better choice to repair foundation cracks; mainly structural foundation cracks. Click on this hyperlink for a comparison of epoxy and polyurethane injection methods for sealing cracks.

 

How polyurethane injection works

 

Polyurethane injection typically involves a high pressure (usually 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 hole 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 or externally) that are leaking; Note: an epoxy injection is not appropriate for use in improving 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

• Honeycombing

• Pool bottoms (when access is possible)

• Seams created by a cold pour

• Overhead concrete structures

• Gaps in the window frame and the top of the concrete wall cut-out

 

The attributes of polyurethane (PU) resin

 

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 basement leak in a poured concrete structure, under all conditions. This versatility is attributable to the characteristics of our polyurethane resins which are:

 

• Our activated polyurethane typically expands to 2.5 times its volume; this is very desirable when filling large cavities or when the size of a hole 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 coping 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 which makes them suitable for use with potable water systems such as cisterns

• Polyurethane sets rapidly in the presence of hydrogen. Since hydrogen molecules are a component of water (H2O), the presence of water during an injection increases the reactivity of the polyurethane which makes polyurethane the ideal product to use when active basement leaks or significant hydrostatic pressure

• The polyurethane resins that we use will not freeze and always remain flexible (not an attribute of all polyurethanes); this is desirable when the concrete surrounding it expands and contracts due to thermal cycling

• Polyurethane sets very quickly which is essential in stopping leaks where significant hydrostatic pressure is present

• Polyurethane injections are conducted using hydraulic hoses which are crucial when accessibility to the repair area is limited