10/21/2026
More renovations, more window installs — and the callbacks we hear about most trace back to the rough opening, not the window.
A certified U-value only holds if the installation does not undercut it. The sequence we walk contractors through:
1. Measure the rough opening at three heights before ordering and build the order around the smallest dimension, not the nominal wall opening.
2. Inspect the sill before flashing. It should be sound, level and draining outward.
3. Flash in sequence: sill pan first, jamb tape lapping over the sill, head flashing lapping over the jambs. 3M 8067 flashing tape applies down to −17.8 °C, so a January opening is not an excuse.
4. Test the air seal before drywall goes up. Finding a gap at final inspection is the expensive version.
We supply the materials; the sequence decides whether the spec holds. Tape and windows: link below.
https://vybuild.ca/product/3m-all-weather-flashing-tape-8067-4-x-75-ft-slit-liner/?utm_source=facebook&utm_medium=social&utm_campaign=organic_2026-10&utm_content=1ad3e288