Want to know more about Insulation and Green Building Practices

Green from the Ground Up - Upcoming Training

Intensive 2-Day Classroom Program
In this two-day course, David Johnston teaches participants how to approach a home from the green building mindset.

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More About Insulation

What are the advantage and disadvantage of interior and exterior insulation. Review the list below to learn more and decide which strategy is right for your project.

Interior Insulation


  • It is simpler to install on existing foundation walls.
  • Material costs may be low since you can use almost an insulation material.


  • Many types of insulation require separation from habitable  spaces by a fire-resistant material, since they are often extremely flammable and will release toxic gases if ignited.
  • It reduces usable interior space when retrofitted.
  • It fails to protect the waterproofing membrane.
  • It may become saturated by moisture.

Exterior Insulation


  • It minimizes heat loss through the foundation.
  • It protects waterproofing membrane.
  • It can serve as a capillary break to block moisture infiltration.
  • It prevents freeze-thaw cycle damage to foundation.
  • it reduces interior moisture.
  • It does not reduce usable interior space when retrofitted.


  • Installation is more difficult than interior insulation in retrofits.
  • Material cost is higher.
  • Some exterior insulation materials are susceptible to insect infestation.