Westlake Royal Building Products has introduced a 5/8-inch Lap Siding profile to its TruExterior Siding & Trim line. The new profile features a true 5/8-inch butt edge designed to replicate the thickness and shadow lines of traditional cedar lap siding.

Made from a proprietary poly-ash blend of polymers and fly ash, the siding offers dimensional stability and resistance to warping, cracking and splitting. It does not require sealing of cut ends, can be installed in ground-contact applications and is paintable in a full range of colors, including dark hues.

The product can be cut and fastened using standard woodworking tools and allows fastening close to edges without pre-drilling.

The 5/8-inch Lap Siding profile is a finalist for the 2026 Best of IBS Awards in the Best Outdoor Product and Most Innovative Building Material categories.