Installation Instructions

CertainTeed Vinyl Siding Installation Guide
46
rain tab
1"
1"
rain
tab
1"
rain
tab
1"
1"
1"
rain
tab
1" or
dimension
of J-channel
face)
Installing Window and Door Trim
Install J-channel along the top and sides of door casings and
around windows.
NOTE: When installing J-channel around replacement
windows that do not have nail flanges, add flashing for
greater protection against water infiltration. For an example
of completed flashing, see the previous page.
There are two methods of joining J-channels at corners. The
easiest method is to square cut the corners. For a more finished
appearance, you can miter the corners. To prevent gaps, do not
butt ends. Instead, lap them as shown.
To square cut corners
Install J-channels at the sides of the windows. Notch them
as shown.
NOTE: For best results, use aviation snips when cutting
J-channel.
Cut the top and bottom J-channels so the ends extend beyond
the casing to the width of side J-channels.
Place the top J-channel along the casing shoulder and nail it to
the wall.
Make two cuts in the bottom of the upper channel and bend it
down to overlap the side J-channel. Repeat for the other side.
This forms a water drain and allows the J-channel to receive
siding panel.
Nail the bottom J-channel in place. Cut the channel as previously
described. Fold the rain tabs into the receiving pockets for a
tighter miter joint.
To miter cut corners
For best results, make sure you cut all J-channels to the proper
length, leaving the proper allowance for the width of the face of
the J-channel.
Square cut the bottom J-channel so that its ends extend beyond
the window casing to the width of the face of the side J-channels.
Notch the ends for clearance. Position and nail the J-channel.
Measure the side J-channels, adding the width of both the top
and bottom J-channels. Miter cut (45° angle) the lower ends
of both side J-channels. Notch the channel to form a rain tab,
position it and nail.
Mark the top J-channel so its ends extend beyond the casing to
the width of the side J-channels. Miter cut (45° angle) the ends.
Cut and bend rain tabs. Position and nail.
NOTE: You can create blind miters on a J-channel using a
J-channel cutter.