Prep and handling
Before installation, store PVC trim boards flat and covered in a dry, shaded area. Avoid prolonged exposure to the sun before the product is installed, and always keep boards clean. Dirt and grime can affect paint adhesion and sealant performance later on.
PVC trim should only be installed over solid, flat substrates. Uneven or flexible backing can lead to movement and poor performance.
Cutting and milling
PVC cuts and mills like wood, but with a few best practices.
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Use standard woodworking tools equipped with carbide-tipped blades
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Avoid fine-tooth blades designed for metal
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Support boards during cuts to prevent chatter and splintering, and lightly sand cut ends if needed
If you're routing or shaping the trim, standard woodworking equipment will do the job. After milling or cutting, wipe the surface with acetone to remove dust and open the pores for better bonding or painting.
Fastening guidelines
PVC trim should be fastened using stainless steel screws or hot-dipped galvanized nails. Avoid using brads, wire nails, or staples (they don’t offer enough holding power).
Here’s what to keep in mind:
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Fasteners should penetrate at least 1.5 inches into framing
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Use two fasteners per framing member
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For boards wider than 12 inches, fasten every 8 inches across the width
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Pre-drill only when necessary (e.g., in cold weather or near board ends)
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Nail guns should be set to 70–100 psi
If you want a concealed finish, plug systems like Cortex or Starborn are great options and designed specifically for PVC.
Adhesives and bonding joints
Cellular PVC can be glued or bonded using an approved adhesive such as TrimGrip™ Adhesive . For the strongest joints, apply adhesive to both surfaces and fasten or clamp them within five to ten minutes of application.
Scarf joints are preferred over butt joints, especially for long runs. When using butt joints, apply adhesive to the back, double fasten on each side, and back the joint for additional stability.
Sealing and finishing
To seal joints or fill gaps, use a high-quality sealant: polyurethane, urethane, polymer blends, or acrylic caulks all work well. Avoid silicone, which may not adhere properly.
Nail holes can be filled with color-matched fillers or plug systems. Larger gaps can be filled, sanded smooth, and then painted or top-coated.
Always clean the surface before painting or sealing for the best results.
Expansion and contraction
Yes, PVC trim does expand and contract with temperature. This is one of the most important installation considerations.
To account for movement:
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Leave a 1/16 to 1/8 inch gap per 18 feet of material
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Fully fasten boards along their length to reduce shifting
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Leave room at ends for movement, especially in corners and long runs
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Bond joints when possible to reduce separation
If you're painting PVC a dark color, use a solar reflective paint to minimize heat absorption and reduce movement. We go into more detail on this in our blog: Can you paint PVC trim?
Painting PVC trim
Painting isn’t required for performance, but it can help seal cut edges and improve appearance, and we always recommend it. It’s especially helpful in keeping milled edges cleaner over time.
Here’s what to know:
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Use 100% acrylic latex paint
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For darker colors (LRV of 56 or less), use solar-reflective paint to prevent heat-related warping
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Let paint cure for up to 30 days before pressure washing or sealing
If you’re painting after installation, wait until the trim is fully fastened to avoid touch-ups around nail holes or cut ends.
Learn more about painting PVC trim.
Cleaning and maintenance
PVC trim is easy to maintain. For general cleaning, use mild soap and water with a soft cloth or sponge. For more stubborn stains, Soft Scrub with Bleach or Clorox Outdoor works well.
Avoid harsh chemicals or abrasive scrubbers unless specified by the manufacturer. Regular rinsing can help keep painted or unfinished trim looking new for years.
Need help choosing the right trim or getting installation advice?
If you’re unsure which trim material is best for your project or have questions about the install process, we’re here to help. Contact us for support, product guidance, or help sourcing the right profile for your next build.