Ply Gem Trim Moulding 101, What is cellular PVC trim and moulding

What is Cellular PVC Trim & Moulding?

Cooking and home design share more than one attribute, but perhaps the strongest is that, in both, it’s the little things that make the biggest impact. So it goes with the trim and moulding on your home. Often treated as an afterthought, these details of your home do more than connect one surface to another — they also tie your home together aesthetically.

Ply Gem trim molding home

Cellular PVC: A better way to detail your home.

Ply Gem window trimTrim and mouldings are typically made of wood, engineered wood, aluminum, vinyl, fiber cement or, the new favorite, Cellular PVC. Extruded on a manufacturing line using either the Celuka® or Free Foam Extrusion process, Cellular PVC installs like wood using standard tools, but can be cut and formed to fit the contours of your home. Arches, angles and unique window headers are all possible with Cellular PVC. It compliments any siding material, from wood fiber cement and stone to vinyl — some manufacturers offer specific products designed to work with vinyl siding, which eliminates the need to settle for the easily available, but boring and oh-so-basic J-channel trim. Best of all, Cellular PVC is virtually maintenance free.

Ply Gem trim columnHint: Know your options.

The best manufacturers offer Cellular PVC Trim and Moulding in a variety of sizes and styles, so it lends itself to many uses, including fascia, deck edge, decorative trim, around windows and doors, as column covers, as frieze and skirt boards … you get the idea. Consider choosing a brand that offers a wide variety of sizes, thicknesses and finishes — and carries at least a 30-year warranty.

Versatile and designed to last.

Ply Gem window trimUnlike wood and other wicking-prone materials, Cellular PVC trim and moulding can be installed below grade and direct to masonry. The material doesn’t contain moisture and won’t absorb it, so it won’t rot, warp or crack. If you paint it, water does not escape, so paint does not peel in the way that is commonly seen in wood trim as it dries over the years. Your paint will last much longer. Cellular PVC trim and moulding is naturally pest resistant, and thus is free from carcinogenic chemicals often used as pest treatments. The right woodgrain design may also resist dirt over the years, as well.

Easy to install.

Cellular PVC trim and moulding is easy to install on the job site. It nails and glues without splitting, cracking or de-laminating. Caulking and sealing not required after installation. It is prefinished in a natural white color with most manufacturers and, if you choose, it is prepped for painting. And they’ll hold the paint longer than wood or other materials due to the material itself, and the paint-friendly wood grain texture.

Ply Gem Trim moulding detailThe Extrusion Difference

Cellular PVC trim is made from poly vinyl chloride via one of two processes.



  • Individual boards made from individual dies
  • Many boards from a single wide sheet
  • Process similar to window extrusions
  • Process similar to vinyl siding
  • Fewer product options
  • Many product options
  • Edges are sealed; edges are rounded (unlike pine boards)
  • Edges are saw cut or sealed with technol; edges are crisp (like pine boards)

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