Measure the distance between the channels.
How to install vinyl siding soffit and fascia.
This video covers installing the fascia and proper nailing.
Cut the soffit panels to the measured size.
Slide one end into the j channel and nail the far side of the soffit to the wood fascia board using one nail to keep the soffit in place until you install the vinyl fascia.
Determine the preferred method of installing soffit at the fascia board.
Attach an f channel to the bottom outer edge of the fascia board.
Subtract inch 6 4 millimeters to allow for expansion.
Certainteed installation guide for vinyl carpentry soffit fascia.
Use the following instructions for vinyl soffit and fascial installation.
Cut your soffit pieces.
Place the soffit panels in the channel slots so that the panels meet.
If the soffit is to turn a corner cut and install j channel to allow 1 4 6 4mm for expansion at each of the adjoining walls and fascia boards.
Since soffit runs perpendicular to the wall you will be cutting many short pieces depending on the width of your overhang.
When installing j channel at either wall of fascia board nail every 8 to 12 203mm to 305mm.
For open overhangs use f trim which has been nailed to the wall of the house.