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Pressure-equalized window installation research update

January 15, 2024  By Jon Eakes

Results are coming in from community college studies initiated by Jon Eakes into window installation methods designed to minimize water ingress around casement frames. Eakes has issued the report below and will appear on a Fenestration Canada webinar Jan. 18 to explain the research progress so far.

This window installation research newsletter started over four years ago and is finally reporting some concrete results after having been put on ice for a pandemic.   Click on this link to get access to the archives of these newsletters dating back to 2019.

Initiation of the project in 2019
After presenting my ideas to several window industry conferences, I succeeded in initiating two research projects on the use of pressure equalized rainscreen principles in the window/wall interface itself, totally independent of the presence or absence of a rainscreen with the wall siding. The first project was with the BETAC labs of Red River College in Winnipeg which included quantifying the question of a thermal penalty for trading off some insulation space in the interface to allow for a pressure equalized drainage path around the window.  The second project was with George Brown College in Toronto specifically on the applicability of pressure equalization in low rise residential window installations.

The original visualization
The original 2019 introduction of the issue of applying rainscreen principles to the window/wall interface can be found here, including an interesting video of a transparent lab maquette.


George Brown College Report
After a shutdown for COVID and thanks to a pretty good staff retention, the final George Brown College report on Pressure Equalization in the residential window/wall interface is now public.  The landing pad for the George Brown College report and other related and upcoming material, including some video clips from GBC, and a link to Joe Lstiburek’s work on pressure equalized residential window profiles, can be found on my website through this link.

Fenestration Canada has asked me to join a webinar to discuss the George Brown College report Wednesday afternoon, January 18, 2024 – so join us live for that discussion.
Everyone is invited to an open Zoom webinar
When: Jan 18, 2024 01:00PM Eastern Time (US and Canada)
Topic: Tech Talk with Jon Eakes on the
George Brown Research Project
Register in advance for this webinar:
After registering, you will receive a confirmation email containing information about joining the webinar.

Red River College BETAC Report
Following the COVID shutdown, BETAC experienced a total turnover of staff from the bottom to the top.  As the lab came out of the pandemic the new staff chose not to include me in the evolution of the project that I had initiated in 2019, although I did learn that the thermal study was concluded in the fall of 2022, other moisture penetration studies were completed in the Spring of 2023 and the data was analyzed in the summer of 2023.  I was told in the fall of 2023 that the thermal study results appeared very encouraging for developing detailed specifications related to the position and size of the pressure equalized drainage paths would be released very soon.  If and when it is made public, I will include it on my site alongside the GBC study report at the link above..

If you would like to find out more about this project, the Executive Director of BETAC, Alireza Kaboorani, invites you to contact him directly: akaboorani@RRC.CA

A quick refresher:
As far back as 2005 the practice of sealing the weather barrier of a house to the frame of the window in an effort to control moisture penetration was questioned enough to justify 7 years of research at the IRC (Institute for Research in Construction) of the NRC (National Research Council of Canada).  The guiding light that came out of that detailed scientific research was: “Don’t try to stop the wind and the rain on the same plane.”  Few people paid any attention.  But the evidence is growing to change things, while residential windows still have water penetration problems.

The NBC now requires providing a drainage path at the window sill.  The CSA A440.4 already supports rainscreen construction and is looking to pushing further in the next revision – which could influence the next code cycle.  Back in 2014, Joe Lstiburek for one has proposed designs for residential window pressure equalized window frame profiles; details on my website. Murry Frank, for one, is already teaching these techniques in Vancouver.

The research I am instigating is designed to quantify all of this with the objective of helping manufacturers, installers and inspector to move from theory to practice with confidence.

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