by Timothy Ahrenholz

Published on March 20, 2019.

Think of a wall like a defending army: a smart commander will place each squad where its strengths will be maximized and its weaknesses defended. The task of assembling the components of framing, cladding, insulation, structural sheathing, and various control layers into a durable, cohesive system is a similar balancing act, but there are solutions. I think of it like my mother telling me to clean my room. She would always say “a place for everything, and everything in its place.” 

Start with framing and other structural elements, which are clearly necessary to any structure. In order to maintain their toughness, they must be protected from water, condensation, and temperature cycling.  This would dictate encasing them within a water resistive barrier, air barrier, vapor retarder, and continuous insulation.  These control layers, on the other hand, are susceptible to damage from wind, precipitation, and UV degradation. So they get protection via cladding installed on top of them.  This is the basic reasoning behind what is sometimes called the perfect wall, and which we have highlighted in a series of articles and videos (see list below).

This is certainly not the whole story, as questions such as how much insulation and how permeable a vapor retarder to use will vary based on your project.  To get insight into these intricacies, take advantage of the excellent collection of resources on this site, which address all applications of continuous insulation as well as every aspect of the design, installation, and compliance of building envelopes.

Get off to a head start with this short video, the most recent in a series we have been highlighting:

For additional information, review the following articles, as well as the previous videos in this series:

Perfect Wall Articles

  1. Creating the ‘Perfect Wall’: Simplifying Water Vapor Retarder Requirements to Control Moisture
  2. Perfect Walls are Perfect, and Hybrid Walls Perfectly Good
  3. Wood Framed Wall Insulation Calculator Explained
  4. New Wall Design Calculator for Commercial Energy Code Compliance
  5. Energy Code Math Lesson: Why an R-25 Wall is Not Equal to a R-20+5ci
  6. Continuous Insulation Solves Energy Code Math Problem

Video Series

  1. Fear Building Envelopes No More with This Website & Videos
  2. Video: Thermodynamics Simplified Heat Flows from Warm to Cold
  3. Video: Moisture Flow Drives Water Induced Problems
  4. Video: How the 'Perfect Wall' Solves Environmental Diversity
  5. Video: How Important Is Your WRB?
  6. Video: A Reliably Perfect Wall Anywhere
  7. Video: The Best Wall We Know How to Make 
  8. Video: How to Insulate with Steel Studs
  9. Video: Thermal Bridging and Steel Studs
  10. Video: Better Residential Energy Performance with Continuous Insulation
  11. Video: How to (Not) Ruin a Perfectly Good Wall
  12. Video: Tar Paper and Continuous Insulation? No Problem!
  13. Video: Do CI and WRBs Go Together?
  14. Video: Assess Your 'Perfect Wall' Using Control Layers
Originally published by: SBC Magazine