Flashing Against Existing Panel Siding

Using a metal j flashing between these types of transitions provides a barrier between siding and transitions that protects against water intrusion.

Flashing against existing panel siding.

It is always recommended to install step flashing behind stucco dryvit wood panel lap siding vinyl siding cedar shingle siding etc. Measure over from the other panel to mark the top and bottom of the vertical cut and snap a line between the marks. In certain instances flashing may need to be installed on the exterior of siding. Hold a panel at the correct height and against a window or other obstruction to mark for the horizontal part s of a cutout.

On a wall to be covered with wood cement board vinyl or metal. Again allow for a 1 4 inch gap. However in most instances step flashing should be installed behind siding. Install the flashing before you finish the top of the brick wall as the flashing must go behind the siding as well as behind and under the top row of bricks that angle outward to cover the top.

Install the kickout flashing underneath the first shingle photo 1. A key part of my approach is using a special piece of flashing at this vulnerable intersection called kickout flashing or kickout diverter. Unless you re careful step flashing can allow water from the roof to slip behind the gutter and get behind the siding and even the housewrap. Since newer installation guidelines do not recommend caulking this joint but instead recommend leaving a small gap and flashing behind the ends of the siding i think it is more prudent to add flashings when it is possible to do so.

Cut 1 4 inch above the flashing or window. But the j cap also creates a consistent line. Begin at either end of the wall and set the level middle section of the z flashing onto the top edge of the siding panel with the wider flange upward and against the wall framing.