1. Does PVC trim require a primer?
A primer is only needed if you want the paint manufacturer’s warranty. Excellent adhesion can be achieved by properly cleaning the board before applying a topcoat of paint to PVC trim. (Refer to painting guidelines in the Versatex contractor handbook for more information on painting PVC trim.)
A Note from the Publisher:
WARNING: POTENTIAL CONFLICT OF INTEREST!!
If you are sensitive about articles that seem to favor a particular manufacturer, then DON’T read this one!! It’s written by the President of Versatex! But after years of experience, I’ve found that some manufacturers know more about their products than anyone else; if a carpenter wants to learn the best way to install a product, sometimes the best source of information is the manufacturer. In the future, look for more carefully-screened articles from manufacturers.
2. What type of paint do you recommend for coating PVC trim?
Just about any 100% acrylic latex, or 100% acrylic latex with a urethane additive, can be used to achieve superior coating durability and flexibility. Lacquers are not recommended with PVC trim because lacquers are a more brittle coating, and will not flex with any movement in the PVC trim. Paints like Duration by Sherwin Williams, Manor Hall paints by PPG and Moorelife by Benjamin Moore adhere well to PVC trim.
Paint on PVC trim will last three to five times longer than paints on wood or wood composites due to the absence of moisture in the substrate. Sherwin Williams also offers a field-applied coating under their “Green Seal®” product designation. Kem Aqua® BP Enamel is a water-reduceable polyurethane, acrylic topcoat that offers fast dry times and no critical re-coat times. Due to its excellent adhesion properties, it is an ideal coating for Cellular PVC.
3. Can PVC trim be painted dark colors?
Only light-to-medium colored paints—with a light reflective value of 55 units or greater—should be applied to PVC trim. For example, using paint with an LRV below 55 units will void our product warranty. LRV is measured based on color and its ability to absorb heat. Thus, an LRV of zero (0) is black, and an LRV of one hundred (100) is white. Don’t assume the paint is a light color. We have had cases where contractors believed that the paint they used was a light beige, only to find out it had an LRV in the 20s or 30s. Consult the paint manufacturer for the LRV of your paint before applying it to cellular PVC trim.
4. How long does it take the paint to cure on PVC trim?
That depends on the weather conditions. Warm/dry weather, or warm/humid weather, will allow the paint to cure faster than cool weather. It can take up to 30 days for paint to fully cure on PVC trim, because PVC trim is impervious to moisture. For the paint to cure, the moisture must evaporate through the surface of the coating that has skimmed over from drying.
5. What is the best glue for joining two pieces of PVC trim? What is the best glue for bonding PVC trim to wood? How about metal?
We recommend PVC pipe glue with solvent for bonding the ends of PVC trim boards to themselves (Weld-On 705 by IPS, TrimTight by Trim Glue, Inc. or Christy’s Red Hot). Be sure the PVC pipe glue has sufficient working time to allow you to apply the glue and push the boards together before it cures.
If you are looking for more of a structural bond at shiplap or scarf joints, miter cuts (window surround), or for gluing sheets of PVC trim, we recommend PVC TrimWelder. For bonding to wood, we recommend Liquid Nails Sub-Floor Adhesive or Heavy Duty Construction Adhesive. For PVC trim to metal, PVC TrimWelder Adhesive works best.
There are three types of PVC TrimWelder Adhesives. Slow and Fast Cure for field joints and small glue-ups, and Laminating Grade for sheet glue-ups. Slow Cure should not be used at temperatures below 40°F. Remember to apply any adhesive to only one bonding surface, thus allowing the adhesive to penetrate into the cells on the other trim piece.
6. What is the best fastening system for PVC trim that also hides the fastener head?
The best overall system for securing PVC trim is the Cortex Concealed Fastening System. It combines the advantages of using screws (strong connection) with the PVC trim tapered plug that fits into the hole created by the screw, thus eliminating the need for fillers or sealants to fill the nail holes. When comparing the cost of this fastening system to nails, keep in mind that you won’t have to go back over the trim filling in the nail holes.
7. What are your recommendations for dealing with expansion and contraction?
Use 8d stainless steel annular shank nails, or screws that are designed for wood trim, and are long enough to penetrate the solid substrate a minimum of 1 1/2 in. Simpson Strong-Tie makes an 8d nail with a 7d head in a 12-gauge thickness, available loose or collated, allowing it to be gun-nailed. The nail is called the “Trifecta.” It is half annular (tip) and half ring-shanked, and made from 316 stainless.
Screws are better for limiting the thermal movement of the trim. Allow PVC trim to acclimate to outside temperatures before installing. Bond PVC trim joints to prevent separation. Be sure to allow adequate expansion and contraction space at the end of long runs. If possible, decrease the on-center spacing between fasteners to 12 in. or less, and bond boards to substrate when practical.
Where you have an expansion joint, leave a full 3/16-in. gap when installing on a day where temperatures range from 30°F to 40°F. Leave a gap just large enough to accept a bead of sealant, or no gap at all (adhesive bond), when installing on a day when temperatures range from 80°F to 100°F. Shiplap joints are superior to scarf cut joints, especially on long runs.
If practical, install long runs of trim when the outside temperature and the temperature of the PVC trim board is 55°F to 65°F, in order to minimize thermal movement in the trim.
8. What is the best way to secure PVC trim to masonry?
Trowel the masonry with a sealant or adhesive to provide a level surface to accept the PVC trimboard. Then secure the trim to the masonry with Tapcon masonry fasteners.
9. How do I seal the open cells if I cut the PVC trimboard? Also, how do I clean PVC trimboards?
Handle PVC trim as you would a piece of premium lumber. Be careful not to damage the visible surface of the board. To seal cut edges or clean a cut edge that has gotten dirty, sand them with 320 grit sand paper, and then wipe the edges with Acetone—this will help to re-seal the cells.
To remove dirt and grime from the visible surface or edges of PVC trimboard, use Soft Scrub with Bleach, one of a variety of Clorox products (Clorox Outdoors, etc.), Mr. Clean Magic Erasers® with a little water, or Corte Clean, a composite deck cleaner that has been found to clean cellular PVC trim. As with any new product, try the cleaner in an inconspicuous area before cleaning the trimboards on your project.
10. What are the recommended sealants I should use with PVC trim?
As with adhesives, look for products that contain some type of solvent. NPC Solar Seal #900 Sealant/Adhesive in Trimboard white #111 has been found to be one of the best sealants for sealing and bonding PVC trim to itself, as well as many other substrates. Other recommended sealants include Quad and EP-1000 Enhanced Polyurethane by OSI, and Geocel 2300, or other polyurethane sealants. Do not use silicone sealants, as they are not compatible with cellular PVC trim.