WRB, window flashings, and window install
joenorm
| Posted in General Questions on
Hello all,
I’ve got CDX sheathing up and taped with Zip tape for air sealing.
Windows are arriving at the end of the month, and I have yet to install the Tyvek commercial D wrap that I will be using for a WRB.
My question is about what to use for window flashings and what is the best order to window install. I see on the Tyvek website windows can go in before or after the application of the Tyvek. Is one method better that the other?
Also curious about window flashing details, Is it worth exploring fluid applied membrane for this or just sticking with Flexwrap and straight flash?
Thanks
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Replies
Hi Joe.
Fine Homebuilding just covered just about every combination of window/WRB install in a series of really good videos. I think the easiest place to find them all together is on Youtube:
https://www.youtube.com/playlist?list=PLv8J8XldbK3_tpUfAfRWryGPdQdkiIjVQ
Honestly Joe, I don't see a hill of beans worth of difference between the two Tyvek installation methods. Most builders prefer to get the windows in as quickly as possible, so they do it before the house-wrap. Since the advent of flashing tape I prefer to do it after. What neither video shows is a metal head-flashing with end-dams. Something that should be considered a must-have in the PNW where you are.
Thanks, that video series is great.
Malcom, I'm leaning toward Tyvek first as you suggested. I assume the head flashing gets slipped under the Tyvek as the windows go in? Is an "end-dam" folds at the edges to redirect water out instead of to the sides?
Cut the Tyvek at 45 degrees from the top corners of the window and fold back. Install the drip-edge flashing by pressing it down onto a bed of caulking on the window-head, making sure it maintains a slope to the outside. Fasten the flashing and cover the flange with another layer of flashing tape.
A good illustration of end-dams: https://hammerandhand.com/best-practices/manual/1-flashing/1-2-head-flashing/