Square Stock

Shop our S4S (Surfaced Four Sides) square stock in primed finger jointed pine & MDF — a versatile, straight-edged board used for window furring, jamb extensions, casing, and baseboard applications. Clean, stable, and paint-ready right out of the box.

  • Surfaced four sides for a smooth, consistent finish on all edges
  • Ideal for window furring and jamb extensions
  • Doubles as casing or baseboard trim when needed
  • Primed finger jointed pine — dimensionally stable and ready to paint

17 products