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When installing vinyl clad Anderson windows over 1/2″ cdx plywood, what is the preferred or correct method for flashing? I’ve seen strips of felt used bottom first, sides second and top last. I’ve also seen Tyvek only wrapped on the entire wall and into the opening. I’ve also seen a combination of the two.
Assuming the wall will be sided at a later date, which method works the best? And when the wall is sided, should you cover the window flashing with felt or Tyvek, or should it be tucked under the flashing?
Lastly should either of these flashings wrap into the window opening? Is this really necessary?
Believe it or not, in this case one side of the house will have vinyl siding (this side is between houses and in shade and not seen) and the other side and front will have clapboards and will show.
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The way I was taught to do it was to wrap the tyvek sides and bottom into the window opening. Slit the top so that the upper fin can slide under the wrap. We then caulk the window fins and slide the works into place and nail it up (emphasis on level square etc.). I additionally tape the outside of the fins to the tyvek and run a piece of flashing above.
I understand that the process also depends on weather conditions in alot of areas. Blowing rain, heavy sun, etc. Up here its just snow and more snow.
*Jeff, We cut the Tyvek in an x pattern over the opening, pulled the pieces into the opening, fastened and trimmed. Then we applied felt as you described, caulked the flanges (urethane caulk)and installed the window. I've seen other installations where the window was mounted directly to the Tyvek (no flaps) and the flanges wer taped all around with Tyvek tape.
*I don't use tyvek, I prefer building paper but either way, slit the top so the top flange goes under the paper, the paper on the sides is also over the flanges, and the flange below is over the paper.Caulk and nail.I've seen the "x" folded into the window opening alot. Don't see how that keeps water from running behind the window. I've also seen narrow strips of felt used as flashing, but if water can get behind the flanges, it can get behind a narrow strip of felt too.