Does Flashing Go over or Under House Wrap

The house wrap has to be flashed properly to keep the water moving down and out, not down and in. That means you want the upper layers to come down over the top of the lower layers.

Does flashing go over or under Tyvek?

Lap Tyvek® WRB over all flashing (e.g. step flashing, wall to roof intersections and through wall flashings). Weep screeds and expansion joints need to be integrated with flashings and the Tyvek® WRB.

How do you install flashing under existing siding?

Nail the siding, stopping before placing the final nail at the end. Slide half of the piece of pan flashing, oriented vertically, under the end of the siding. Make sure the bottom of the flashing does not emerge at the bottom of the lap siding. Secure the flashing and the siding by fastening them to the structure.