To install exterior window trim, choose between wood and PVC trim options, and then cut the trim to size, attach around the windows and paint. Wood and PVC trim have slightly different installation instructions, so first determine the type of material for the job and then perform the install. Consult a professional with specific questions.
To install PVC trim on exterior windows:
- Pre-assemble the frame
- Perform finish work
When adding PVC trim to an exterior window, pre-assemble the frame on the ground before installing it around the window to ensure accuracy and tight joints. Wood trim is typically assembled around the windows. To cut the trim pieces, use wood-working tools with carbide-tipped blades and bits. To assemble the joints at the frame, pre-drill pocket holes and then use PVC cement and pocket screws to tighten the joints together.
Install the pre-assembled frames around the windows with stainless steel trim-head screws. Stainless steel screws will not rust, which will protect the trim from discoloration or premature replacement.
The exterior temperature matters when installing PVC trim, so for temperatures above 80 degrees Fahrenheit, create a tight fit around the pieces. For temperatures between 60 and 80 degrees, leave a 1/16-inch gap, and for temperatures below 60 degrees, leave a 1/8-inch gap. Use an acrylic or urethane caulk to fill all of the gaps.
Use an exterior filler to fill all holes and sand it smooth once dried. Use an exterior acrylic paint to paint the PVC trim.