Tips for Fastening PVC Trim
Be sure to plan for expansion, use the correct adhesives, and use long-lasting fasteners if you want your PVC trim job to look good for years to come.
Synopsis: Although PVC trim can look like wood, it doesn’t behave like wood, so it requires some unique installation methods. For example, PVC expands as it gets warm, so long runs require a gap at butt ends. Use a scarf joint to join PVC trim boards; use PVC cement for any joint that does not require an expansion gap. Find out more in this video.
Video Transcript: Although PVC trim can look like wood, it doesn’t behave like wood, and requires some unique installation methods. PVC expands as it gets warm, so long runs require a gap at butt ends.
Clear the product shown here requires a 1/8th inch gap per 18 feet when installed at 70 degrees. In hot weather, make the gap a little smaller. In cold weather, make it a little larger. Fill gaps using manufacturer recommended sealant. Just like with wood use a scarf joint to join PVC trim boards.
A scarf is made from two opposing miters that are glued together with manufacturer recommended cement. PVC cement is used on any joint that doesn’t require an expansion gap.
For fastening use stainless steel trim nails so the nails will last as long as the trim. Nail within two inches from the edge of the boards and at least every 18 inches along the length.
You can also use a screw and plug system. This one from Fasten Master has plugs made to match clear products.
Sand smooth with 150 or 220 grit sandpaper to smooth any sharp or rough edges.