Vinyl vs Polyurethane Foam: Does it Really Matter?

There was a time, long ago, when craftsmen would spend their entire working days creating beautiful designs with amazing architectural details all by hand. Each piece would be an original work of art. With today’s technology, we can still have a taste of the old, but at a much more affordable price thanks to products like Fypon and Spectis that cast polyurethane foam in molds creating the look of an antique piece and Durabrac Architectural Components who cut simple designs that look like wood brackets and corbels in PVC/Vinyl.

Whether made from polyurethane foam or PVC/Vinyl, these products allow designers to bring back the look of the past. What began in themed communities can now be found in nearly every town.  So, it bears asking… which one is better? How do you choose which material is best for you?

As the force behind Durabrac Architectural Components, it’s no surprise I’m partial to the virtues of PVC/Vinyl as a building material. But, I’m also a realistic and objective designer who knows that every material has its purpose. To compare PVC/Vinyl to cast polyurethane, you first have to identify its intended use.

It’s my opinion that polyurethane foam is best used for detailed ornamentation such as thick decorative appliques over doors and windows, or ornate corbels. (See picture of a Spectis corbel below.) Because of a much lower surface density, polyurethane components are quite a bit softer than wood, stone, or vinyl and can be easily damaged from bumps and abrasions.  For this reason, it should be installed out of the reach of people and away from any possibility of accidental impact damage.

Ornate corbel  by Spectis made of Polyurethane foam.

Unpainted polyurethane foam does not stand up to the sun and weather very well either.  For that reason, all polyurethane components are shipped factory primed and have to be painted and should be installed in areas where they are protected from the weather and elements. Rain, hail, and birds can cause significant damage.

Hands down, PVC/Vinyl is a better choice for thin components like gable and porch brackets, running trim and spandrel. (See Durabrac spandrel picture below.) Its tough exterior is resistant to impact damage, is UV protected and its natural white color doesn’t have to be painted. Should you accidentally chip the surface of components made from PVC/Vinyl or need to make simple modifications like notching to fit around existing trim, unlike polyurethane, the core is just as UV resistant as the face and is the same white color inside as the exterior. Also, most PVC/Vinyl components are not made in a mold so they are available in just about any size.

Durabrac Spandrel made from 100% Vinyl.

Polyurethane components are cast solid in a mold, which limits the availability in sizes. In addition, the larger and wider a polyurethane component gets, the more material required to create it. This extra material adds up to a large expense. PVC/Vinyl is a better choice for large and over-sized arches, braces and brackets, especially those used in commercial settings. These large, vinyl components are manufactured hollow. The hollow construction allows for a more efficient use of material, keeping the expense lower and waste at a minimum.  (Not to mention, being hollow creates a lighter product that is easier to install. An added bonus!)

Durabrac 0530 Large Arch Bracket

Durabrac Corbel. Notice the hollow construction of both the Corbel and Large Arch Bracket above.

Unlike wood or vinyl, the density of polyurethane foam varies according to specific formulas that control the expansion of the liquid polyurethane in the mold. Density is measured in pounds. It can vary from one-pound density up to a rock hard 60 lbs. density. The density figure comes from how much one cubic foot of cured foam weighs. My familiarity with polyurethane foam comes from my years in the sign industry.  We used high-density polyurethane foam in the past to create carvings and intricate detailing.  We used 15 lb. to 18 lb. density foam. Most cast polyurethane components, I believe, are around a 10 lb. density.

Sign for Bark Avenue. Dog’s head and fine details of its face are carved into Polyurethane foam.

We don’t work with polyurethane foam any more.  It has been over ten years since we switched. We do most of our carving with computer software now—letting the machines carve the fine details in tough PVC/Vinyl. We found the high-density foam to be too brittle for our specific products at Durabrac. It’s like an architect once said to us, “I just can’t put something on my building that I can shove a cheap ballpoint pen through.” You can try, but you’re not going to get a ballpoint pen through a Durabrac component.