Control layers first
Treat the house as an assembly, not a collection of cavities.
Air, heat, water, and vapor move through the whole enclosure. These guides make those interactions visible.
Air Barrier vs Vapor Retarder: Different Jobs
See how air, vapor, bulk water, and heat control layers differ, overlap, and connect before spray foam is added to an enclosure.
Read the guideSpray Foam, Moisture, Condensation, and Drying Potential
Separate bulk water, air-carried moisture, vapor diffusion, and built-in moisture before deciding whether spray foam belongs in an assembly.
Read the guideA useful next step
Turn the reading into a plan.
Answer seven practical questions and see which conditions to investigate before choosing a material.