In this episode, our hosts are joined by Tom Harris, a spray foam insulation expert, who discusses the topic of hot roofs and the proper installation of spray foam insulation. He explains the concept of hot roofs, where the thermal boundary is moved to the roof deck, and the different applications and challenges associated with hot roofs. Tom emphasizes the importance of proper installation and the choice of spray foam type based on climate and region. He also discusses the need for thermal barriers and ignition barriers to protect the foam and comply with building codes. Additionally, Tom addresses concerns about shingle warranties and provides insights into foam recommendations for different climate zones. In this conversation, Tom Harris discusses the limitations and capabilities of different insulation materials, including fiberglass and spray foam. He explains how fiberglass insulation can transport air and degrade thermal efficiency, while spray foam acts as an air barrier and doesn't get wet. Tom also discusses the requirements for ignition barriers and fire barriers. He highlights the importance of properly insulating crawl spaces and attics and the benefits of using spray foam in these areas. Finally, he addresses the potential issues of using closed-cell foam directly on the interior of foundation walls without exterior waterproofing or damp-proofing.

Takeaways

Fiberglass insulation can transport air and degrade thermal efficiency, while spray foam acts as an air barrier and doesn't get wet.
Spray foam outperforms its stated R-value by adding concepts of air barrier and moisture control.
Ignition barriers and fire barriers are important for safety and code compliance.
Proper insulation of crawl spaces and attics is crucial for energy efficiency and comfort.
Closed-cell foam is a good option for insulating foundation walls, but exterior waterproofing or damp-proofing is recommended.

Chapters

00:00 Introduction and Background
03:01 Understanding Hot Roofs
06:04 Proper Installation of Hot Roofs
09:01 Choosing the Right Spray Foam
11:58 Protecting Foam with Thermal Barriers
20:59 Identifying Thermal Barriers and Ignition Barriers
24:57 Foam Recommendations for Different Climate Zones
28:04 Importance of Air Leakage Control
29:01 Limitations and Capabilities of Insulation Materials
32:07 Ignition Barriers and Fire Barriers
40:41 Insulating Crawl Spaces and Attics
45:37 Insulating Foundation Walls