Another way to easily trim an arch is with flexible polymer molding—it is cheaper than custom wood curves; cuts with standard woodworking tools; is paintable and stainable; and won't rot, warp, or crack. Some products such as Flex Trim (shown) are even tooled to simulate wood's natural grain. Here are TOH general contractor Tom Silva's tips for building with bendable profiles:
? Use only what you need
Yes, it's cheaper than custom wood curves, but flexible moldings still cost more than most straight profiles (about $8.50, compared with $1.15 a linear foot for a simple pine profile). So use it only where you need bending action.
? Measure twice
Companies stock many standard arch sizes, but for a custom job, you'll need to create a template of your arch by tracing its outline onto kraft paper. To match the curve to existing leg casing, send the company a molding sample with the template.
? Fasten tight
Flexible molding can droop over time. So in addition to polyurethane construction adhesive, use plenty of trim screws—at least one every 16 inches.
? Lay it on thick
Since flexible moldings don't absorb stain like wood, you'll need more coats to get a good match. Instead of brushing it on, Tom suggests using a spray-on finish, which helps prevent streaking. Gel stain applied with a rag also works well.