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.

More About Insulation

• Types and Materials
• Insulation Choices and Strategies for a Zero Energy Home

Interior Insulation

Advantages

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

Disadvantages

• 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

Advantages

• 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.

Disadvantages

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