Versatile and essential for countless interior finishing projects, our selection of flat stock offers clean lines and endless possibilities. Also known as S4S (surfaced four sides) lumber, flat stock is ideal for creating custom trim, casings, baseboards, window and door accents, shelving, or modern minimalist moulding. We carry a wide selection of sizes, profiles, and species—including MDF, pine, fir, hemlock, and more—so you can find the perfect material to suit your style and project needs. Whether you're building new or updating an existing space, flat stock provides a simple, refined look that works beautifully in both traditional and contemporary designs. As a proudly Canadian company with locally owned stores, Windsor Plywood offers hard-to-source materials, quality craftsmanship, and expert advice. Visit your local store to browse our full selection of flat stock and find exactly what you need to bring your vision to life.
Windsor Plywood carries pine lumber in construction, select, and finish grades including SPF framing lumber, clear pine boards, finger-jointed pine trim, and knotty pine panelling. Pine is one of the most widely available and versatile species, used for framing, interior trim, furniture, shelving, and decorative panelling.
Clear pine is graded to minimize or exclude knots, producing a consistent, smooth surface suitable for painted or stained trim, furniture, and millwork where a clean appearance is required. Knotty pine grades allow knots as a design feature, producing the rustic, characterful appearance popular in cabin interiors, panelling, and country-style furniture.
Pine is commonly used for painted furniture, particularly in DIY and production furniture applications. It machines easily, is widely available, and is cost-effective. The main considerations are its softness relative to hardwoods (it dents more easily) and its tendency to blotch when stained without conditioner. A shellac-based primer seals the resinous wood and provides a better base for paint than standard water-based primer alone.
Yes. Pine contains resin, particularly around knots, that bleeds through paint and stain without sealing. Apply a shellac-based primer or knot sealer over all knots before finish painting. For stained pine, apply a pre-stain conditioner to reduce blotchy stain absorption. Failing to seal pine knots results in yellow-brown staining appearing through the finish over time.
Finger-jointed pine is made by machining short pine pieces with interlocking finger joints and gluing them end-to-end into longer boards. The joints are nearly invisible under paint. Finger-jointed pine is an economical and stable alternative to clear pine for painted trim applications. It is not suitable for stained applications where the joints become visible. Windsor Plywood carries finger-jointed pine trim profiles in common baseboard and casing sizes.