How to Install NAPCO Vinyl Siding

Snap a horizontal chalk line, inset by 1-1/2 inches from the base of the backer-board sheathing, between each corner of the house. Align the top edge of the starter strip with the chalk line, and leave a gap from the wall corner to accommodate the corner-post measurement, plus 1/4 inch for expansion. Fasten the starter strip using corrosion resistant nails at 8-inch intervals, leaving a 1/4-inch expansion gap between each strip.

Install inside and outside corner posts, leaving a 1/4-inch expansion gap from the top of the wall or from expected fascia fittings. Align the bottom edge of each post 1/4 inch lower than the base of the starter strip. Fasten each post at 8-to-12-inch intervals, as recommended by Napco.

Push the bottom edge of the vinyl siding plank into the lip of the starter strip, leaving a 1/4-inch gap from the corner post. Fasten the siding to the sheathing through the fastening slots along the top edge. Install subsequent planks into the starter strip, using a 1-inch overlap at the back of the panel between planks.

Continue to install rows of planks, working up the walls and applying an overlap between courses, according to the measurement that your specific Napco siding instructions indicate. Stagger the plank end joints from course to course to minimize vulnerable points in the installation.