On Thursday, August 9, 2018 at 12:13:24 PM UTC-5, Oren wrote:
On Thu, 9 Aug 2018, Davej wrote:
On Monday, August 6, 2018, Oren wrote:
On Sun, 5 Aug 2018 14:25:21 -0700 (PDT), Davej wrote:

In a 20 year old house how common is it to find windows
were not properly flashed? The Tyvek is simply cut out
around the windows. It isn't even taped to the window
frames.

What you have is an installer problem. Some clowns install
windows by piece work. $15 per window will get you three
fasteners an not much else, as to quality of the install.



I don't think it is practical for me to remove and reinstall each
window, so my plan is to remove the vinyl siding and tape the
vinyl window frame to the Tyvek. If there is noticeable deterioration
of the OSB board I will also cut an exterior inspection hole below
each window.

If you do remove (cut back) siding, I'd suggest self adhesive butyl
rubber. Comes in six inch or larger width. It does need to be
"tucked" under the siding (post install repair). Think about how
water runs down the walls. Do the sides first, bottom over that and
the top is last piece so as to shed water so it runs down the wall.

If you see no interior water damage, there may not need to be an
"inspection hole".

I'd use butyl rubber over tape solutions. Just me. Keep the weather
elements out and reduce drafts. You could pull the window trim and
pack insulation around the RO.

I obtained a roll of "Blueskin" rubber tape and a roll of Tyvek
transparent tape. The vinyl windows were nailed and caulked into
their position in the OSB. The Tyvek is merely cut out around each
window. The easiest approach would be to assume that most of the
leakage is at the top and bottom of the window so remove the vinyl
siding to tape the top and bottom of the Tyvek to the window frames.
A better approach would be to remove all the siding around each
window and tape all around each window. The best approach might
involve removing the windows, but that might damage the windows,
so I'm reluctant to consider it. I might also caulk the vinyl siding
trim to the windows to prevent water from so easily reaching the
tape seal -- even though caulk is normally not applied there.