Find Your Store
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.
Frequently Asked Questions
What fir products does Windsor Plywood carry?
Windsor Plywood carries Douglas fir lumber in a range of structural and appearance grades. Douglas fir is the primary construction framing and structural wood throughout western Canada, available in standard dimensional sizes. Clear and select grades are available for interior millwork, flooring, and timber framing applications. Pressure-treated fir for exterior structural use is also stocked.
What makes Douglas fir suitable for structural applications?
Douglas fir has an excellent strength-to-weight ratio, a straight grain that resists splitting, high stiffness, and good fastener holding strength. It is the most widely used structural lumber species in western Canadian construction for framing, beams, posts, and engineered wood products. Its combination of strength, stiffness, and availability makes it the benchmark species for structural wood design tables.
Can Douglas fir be used for interior finished work?
Yes. Clear grade Douglas fir is used for interior flooring, panelling, doors, stair components, and timber-frame exposed structural elements. The prominent straight grain and reddish-brown colour of Douglas fir are design assets in rustic, craftsman, and timber-frame interior aesthetics. It machines and finishes well, though the pronounced grain requires filling for the smoothest painted surfaces.
What finishes work on Douglas fir?
Douglas fir accepts oil-based and water-based stains, though the difference in absorption between earlywood and latewood grain bands can produce variation in stain depth and colour intensity, which is typically considered an attractive characteristic rather than a defect. Penetrating oil finishes complement the natural grain. For painted applications, a quality primer is important to seal the resinous wood and prevent tannin bleed.
What is the difference between construction-grade and clear-grade Douglas fir?
Construction-grade fir is graded for strength with knots, wane, and other characteristics acceptable for structural use. Clear-grade fir is selected for minimal knots and defects, intended for visible applications where appearance matters. Select structural grade balances strength and appearance. Windsor Plywood stocks multiple grades — contact your local branch to confirm the grades available for your specific project.