The BS of BS--the bullshit of building science--is Steve's way of characterizing sound building science gone haywire in totally screwy application. Examples include paralyzing worry over vapor diffusion as a way that buildings get wet, insane levels of exterior insulation in below-grade walls, using only financial payback when comparing double- and triple-pane windows (ignoring thermal comfort and durability). Add in over-insulation of window frames, bans on spray foam, and you have the UBIP combined blood pressure skyrocketing.

Pete's Resources:

1. BuildingScience Info-311: Vapor Open Assemblies - https://buildingscience.com/documents/information-sheets/vapor-open-assemblies

2. Hammer & Hand: Installing European Passive House Windows Exterior Over Insulation - https://hammerandhand.com/videos/installing-european-passive-house-windows-exterior-insullation-video-006/

3. BuildingGreen's Special Report on Insulation: "The BuildingGreen Guide to Thermal Insulation - https://www.buildinggreen.com/continuing-education/buildinggreen-guide-thermal-insulation