Can polyurethane act as waterproofing for cracked foundations?

Although polyurethane spray foam is resistant to water, it has not been specifically evaluated for waterproofing foundations. However, research conducted by the Institute for Research in Construction of the National Research Council of Canada (NRC) from 1995 to 1998 have shown that polyurethane spray placed on the outside of a foundation wall is useful in many ways :

  • It helps to prevent water from contacting the concrete wall,
  • waterproofing of the concrete is not required if the foam is covering the wall and the base of the foundation,
  • water is controlled overground, and
  • it can provide a first line of protection through its ability to control water.

These observations were documented in Construction Technology no. 36 – Performance of Thermal Insulation on Exterior Basement Walls (National Council of Canada Research, December 1999) and the NRC research report, Summary Report on the Evaluation of the Performance of an Exterior Basement Insulation System – Polyurethane Spray Foam (November 2000).