Video: How to (Not) Ruin a Perfectly Good Wall

Originally published by the following source: Applied Building Technology GroupFebruary 26, 2019
by Timothy Ahrenholz

    

In this series of articles (see list below), we’ve been highlighting the benefits that continuous insulation can have in pretty much any wall design. 

Figure 1 - The rigid foam insulated sheathing can be placed exterior of the house wrap, interior of the house wrap, or it can take the place of the house wrap as the wall's drainage plane

But any wall, no matter how well insulated or built, will surely deteriorate if it permits water to intrude. Keeping bulk water out is probably the most important thing that a wall does.  How this is done today is pretty simple: before rain can get to anything it can damage, it hits a continuous drainage plain and runs down until it falls off the drip edge of flashing at the bottom. The details are important here, and to make sure that it works well, all the pieces need to be carefully integrated together. The good news is that integrating continuous insulation and the water resistive barrier is not rocket science. The insulation can simply be installed as found in the Department of Energy graphic Figure 1 at right.

A labor cost effective option with certain products is to use continuous insulation as its own WRB, by taping all seams and overlapping the insulation boards over the flashing (be sure to check that your insulation product is approved for this usage, and follow manufacturer’s instructions).

There are plenty of water control resources available at continuousinsulation.org. A good place to start would be the water resistive barrier topical library. The video below explains the importance of the WRB:

For additional information, please 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. Thermodynamics Simplified Heat Flows from Warm to Cold
  3. 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