Installation Instructions
CertainTeed Vinyl Siding Installation Guide
90
Turning a corner
To turn a corner, measure from the channel at the wall corner to 
the channel at the corner of the fascia board. Subtract 1/4" for 
expansion. If necessary, install nailing strips to provide backing 
for the lineal. Cut and install soffit double channel lineal or H-bar. 
Miter the corner soffit panels and install as described earlier. 
Completing the installation
To complete the installation, apply utility trim and fasten aluminum 
fascia cap or formed aluminum coil stock with painted trim nails. 
If you must face nail fascia, drill holes for the trim nails to allow for 
expansion and to reduce denting of the aluminum.
Installation over enclosed eaves
If the existing soffit is rotted or damaged, it’s best to remove it 
completely before installing vinyl soffit. Then use the instructions 
for open eaves. 
If you’re installing perforated soffit panels and the existing soffit 
doesn’t have openings for ventilation, cut an adequate number 
of openings. Then complete the installation as described for 
open eaves.
The procedure used to install soffit over an enclosed eave is 
almost identical to that used for an open eave. The major 
difference is the installation of the J-channel. Determine the 
method you’ll use to install soffit at the fascia board (see figures 
5 and 6). When installing J-channel at either the wall or the fascia 
board, nail the J-Channel every 12" to 16".
Turning a corner
If the soffit is to turn a corner, cut and install J-channel so there 
is 1/4" for expansion at each of the adjoining walls and adjoining 
fascia boards. Miter the corner soffit panels and install as 
described earlier.
fascia cap or 
coil stock
soffit J-channel
J-channel
soffit
enclosed 
eave
soffit 
H-bar
fascia
nailing strip
enclosed 
eave
Fig. 5
Fig. 6
miter soffit panels










