01/15/2026
At last night’s meetup with , the debate over fully sealed “barrier” window taping vs. leaving the bottom of the RO open for water drainage was alive and well!
I think it boils down to two questions:
1. Do we trust the v***r open tape’s ability to allow sufficient drying potential to manage some amount of water intrusion, if it ever happens?
2. Do we trust the installer doing the taping?
On most of our projects over the past 5 years, we have gone with the full perimeter tape and choose to trust the material and our installation capabilities. While I haven’t tested every project, I have done the ASTM-E1105 water pe*******on test on two projects with passing results.
Video 1 shows the test underway from the interior, where the window is put under depressurization at 10psf for (4) 5 minute cycles at pressure with 1 minute rest in between cycles while a big spray rig soaks the exterior of the window and wall around it. This essentially mimics a hurricane force storm focused on the window without any exterior trim or siding installed. We experienced zero water intrusion.
Video 2 shows the test running on the outside of another window where we did get water intrusion during the test. Someone forgot to tape over four screw holes (they are pretty obvious) where 2x4’s had been installed over the openings to prevent window damage in transport. We taped those and retested on a different day with zero water intrusion.
Video 3 is just for fun as I was riding up the lift to inspect an upper-story window.
It’s very true - if you don’t test you don’t know. But having seen this installation process perform well, I don’t have reservations about continuing to make it our default.
Panelization & Window install:
Architecture:
Testing:
