Installation Instructions

CertainTeed Vinyl Siding Installation Guide

Trimming Bay Window Corners

There are several ways to trim the odd angles of bay windows.

Here are two of them:

1. Install bay window cornerpost.

2. Install J-channel with a quarter-round insert.

Before you begin, make sure the corner is properly ﬂashed.

Install bay window cornerpost

• Cut bay window cornerpost to the proper length.

• For angles less than 45°, push down on the face of the corner

until the nail ﬂanges seat ﬂat against the wall surfaces.

• Hang the cornerpost by nailing loosely into the topmost nail slot.

• Make sure the cornerpost is straight and true.

• Position all remaining nails in the center of nail slots a maximum

of every 8" to 10". Leave 1/8" to 1/16" between the nail head

and the cornerpost to allow the cornerpost to move during

normal expansion and contraction.

• Fit the siding into the cornerpost.

Install J-Channel with quarter-round insert

• Cut two pieces of J-channel and one piece of quarter-round

insert to length.

• Pop rivet the J-channels to each side of the quarter-round insert

in at least three places.

• Nail the assembly to the corner, remembering to hang the

assembly from the topmost full nail slot.

• Position all remaining nails in the center of nail slots a maximum

of every 8" to 10". Leave 1/8" to 1/16" between the nail head

and the J-channel for normal expansion and contraction.

• Fit the siding into the J-channels.

See page 109 for installing bay window corners with

Cedar Impressions Siding.

for angles

less than 45°

for angles 45°

and larger

push down

until nail

flanges

seat flat

pop rivets

remove

half of the

longer leg