Spray Foam Insulation vs. Foam Board

June 5, 2019
niki dube

spray foam insulation vs foam board max insulation

When choosing between closed-cell spray foam insulation and rigid foam board for exterior wall assemblies, the importance of considerations such as price, design integration, and performance cannot be overstated. Spray foam insulation gets high marks in each of these categories making it your best choice for every commercial build. Let’s discuss the differences so you can make the right decision for your project:



  • Increased design flexibility due to expansion upon application, allowing it to fit into tight spaces around window, door, and transition flashing systems
  • Lower overall cost due to reduced labor and material needs
  • Fully adheres to and seals construction gaps and penetration holes
  • 30% higher r-value than rigid foam board
  • Provides energy code required air barrier as well as an effective water barrier and moisture vapor retarder
  • Saves nearly 40% of the cost of foam board
  • 50% faster application than foam board


  • Increased opportunities for penetrations due to mechanical fastening
  • Decreased design flexibility due to self-described “rigidity”
  • Provides insulation and air sealing, as long as seams are sealed perfectly
  • Increased cost to install due to time-consuming installations: cutting panels to exacting sizes, ensuring seal and hold, etc.
  • Spray foam insulation often needs to supplement install to fully seal space between panels and/or hold panels in place
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