Architectural Record BE - Building Enclosure

Continuous Insulation: Spray Polyurethane Foam vs. Rigid Foam Board

Medium density spray polyurethane spray foam insulation (SPF) as an alternative to traditional rigid foam board

Webinar On-Demand
Sponsored by ICYNENE, Inc.
Continuing Education

Learning Objectives - After this course, you should be able to:

  1. Identify the characteristics of high performance continuously insulated exterior wall assemblies.
  2. Compare the characteristics of rigid board insulation with those of medium density spray foam insulation for use in exterior wall assemblies.
  3. Investigate the use of spray foam insulation to achieve multiple performance traits in one product including thermal, air, and water resistance.
  4. Assess the ability of spray foam insulation to be installed with fewer steps and at a lesser cost than assemblies using rigid foam insulation.



The design of exterior wall assemblies has become increasingly focused on performance for greater energy efficiency and resistance to air and water penetration.

The 2015 International Energy Conservation Code and ASHRAE 90.1 now requires insulation that is continuous in wall assemblies, (i.e. not interrupted by studs, framing, etc.) in all eight climate zones within the United States. This push for continuous insulation in exterior wall assemblies is also reflected in green building standards and the desires of building owners to reduce energy costs.

The response by many architects has often been to use rigid foam board insulation located over the exterior structural face and behind exterior claddings.

While this may be a more traditional choice, it is not the only one.

In recent years, significant technology advancements and assembly fire testing results have made spray foam insulation a viable choice for exterior continuous insulation. In fact, closer review suggests that using field applied medium density spray foam insulation may be a better choice for many situations. This has been found to be true when looked at in terms of design flexibility, performance, construction efficiency, and cost.

Photo courtesy of ICYNENE, Inc.


The evolution of insulation starts here. Icynene’s spray foam insulation products are specially formulated to meet the needs of builders, architects and homeowners.