John recently had some second-story stucco replaced and reused his existing windows based on his contractor’s advice. Now, he’s questioning whether the flashing details were done correctly and whether they should be redone.
Question from John: Recently had some stucco replaced on the second story of my home. I took the contractor's advice and reused the existing windows. I have a question regarding the flashing details. They removed the windows, cleaned out the rough opening, and cleaned the nailing fins. They then flashed the rough opening but did not wrap the peel and stick into the sill. The windows were then caulked and put back in.
Tyvek stucco wrap was then lapped around the windows, and they used regular Tyvek seam tape to seal the paper to the nailing fins and frame. Two layers of Grade D paper were then lapped on top of that. Is that correct? Worried we need to do this over again.
Answer: The prep work of cleaning up the rough window openings and window flanges sounds correct, but the flashing details could have been improved. Here’s how I like to install windows to ensure proper waterproofing and to ensure that everything is counterflashed properly:
Tyvek the Wall First: The entire wall should be wrapped with a weather-resistant barrier like Tyvek before installing any flashing.
Install Peel-and-Stick Flashing: First, apply peel-and-stick flashing to the bottom of the window opening. This does not have to be wrapped up into the sill but can be if the installer chooses to do so. Next, apply it to the sides of the window opening, overlapping the bottom piece.
Apply Caulking Around the Opening: I prefer to caulk around the window opening, except for the bottom edge. On the bottom, I only apply caulking six inches in from the corners and leave the middle portion uncaulked. This allows any trapped water to escape.
Install the Window: Once the window is set in place, fastened, and properly squared, the final piece of peel-and-stick flashing should be installed over the top flange of the window to ensure proper counterflashing.
How Does Your Installation Compare?
Your installation was close, but one thing stood out that I personally don't like myself and that is the flashing was installed first and then tyvek over that. If a wind driven rain is strong and the seam tape that was used fails, water only has to travel the width of the flashing (6") before it makes it underneath the waterproofing layers.
Applying the Tyvek first and then applying the flashing over that elimintaes this problem and you have a continuous water barrier.
Should You Redo It?
If the windows are properly sealed and there’s no sign of water intrusion, you may not need to redo everything. However, if you’re worried about long-term durability, the biggest concern would be the Tyvek and flashing not tied in together. If you ever notice water stains, damp drywall, or leaks around the window in the future, this would likely be the cause.
Would I personally redo it? If no water is getting in and you’re past the stucco application stage, I’d probably leave it unless you’re planning another major renovation. If the walls are still open, redoing the Tyvek and flashing around the window would be the best approach.
Let me know if you need further clarification!
