Oftentimes if you re installing in a re roofing situation you re going to be coming up against vinyl siding brick wood.
Flashing against panel siding.
In certain instances flashing may need to be installed on the exterior of siding.
It is used to protect the horizontal joints between sheets of siding from water infiltration.
However in most instances step flashing should be installed behind siding.
In those instances the best thing to do is remove the siding and run the flashing up against the wall and replace the siding so that you have a watertight finish.
Keep water out of your home and running down the roof where it belongs with appropriate use of step flashing.
How to install step flashing under siding.
Even if the roof has been properly flashed against the sidewall this one hasn t water can still run down the side of the house and behind the siding causing rot.
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.
The large leg of the metal goes against the wall leaving the seat and face covering the top edge of the siding.
J flashing on transitions.
The seat dimension 3 8 in corresponds to the siding thickness.
The exterior of a house presents plenty of opportunity for leaks.
The flashing can be used over window trim band boards panel intersections and other vertical surfaces.
One of the most vulnerable areas for siding is transitions.
Use a felt paper spline wrapped around the corner and extending 6 inches beyond the corner board to protect the joints where the siding meets the corner boards see figure 1 5 at left.
Building siding flashing finish details for building corners use overlapping 1x4s or 1x6s at outside corners or use 5 4 stock for a heavier look.
Galvanized steel z flashing is made from 28 gauge galvanized steel.
It is always recommended to install step flashing behind stucco dryvit wood panel lap siding vinyl siding cedar shingle siding etc.
A common problem area is the point where a gutter dies into an adjoining wall as the photo below illustrates.
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.
A key part of my approach is using a special piece of flashing at this.
Installing the z trim.
The solution to rotting sidewalls is a small piece of bent metal called a kickout flashing at roofing suppliers which simply directs all that water away from the wall.
