What house wrap does
House wrap is designed to help shed bulk water that gets behind siding while allowing appropriate drying based on the wall system. It is not a substitute for flashing, and it should not be treated as a cure-all. It is one part of a layered exterior assembly.
Why installation quality matters
Seams should overlap correctly, penetrations should be handled carefully, and window and door openings should be integrated with flashing. The goal is to direct water down and out instead of trapping it inside the wall.
When to update it
Siding replacement is the practical time to inspect and upgrade the weather barrier. Once new siding is installed, correcting hidden wrap or flashing problems becomes much more difficult.
How this affects long-term value
In Seattle, Tacoma, and nearby communities, the weather barrier can be just as important as the finish material. A sharp-looking exterior should also be built to handle wet seasons, wind, and drying cycles.