S4S Finger-Joint

Mid-Columbia's S4S (Surfaced Four Sides) finger-jointed structural lumber has gained wide acceptance in the building and construction industry. Because our structural finger-jointed products are graded using the same rules applied to solid-sawn dimension lumber, the design values for structural glued finger-jointed lumber are the same as those of conventional, solid-sawn lumber. It is accepted for use under all model building codes and is interchangeable with solid-sawn dimension lumber of the same size, grade, and species, and is grade marked accordingly.

Certified Exterior Joints/"HRA" Heat Resistant Adhesive

Finger-jointed products, produced in accordance with WWPA standards and grade stamped "CERT EXT JNTS," are intended for all structural applications.

All materials we produce meet the most rigorous industry standards for fire performance. The "HRA" heat resistant adhesive we use will provide complete trust and confidence that our material will meet fire resistance needs in all markets.

This lumber is assembled with a waterproof, exterior-type adhesive, meeting the requirements of ASTM product standard D2559 and conforming to WWPA's Glued Products Procedures for Mill Certification and Quality Control, C/QC 101. Limitations on knot size and placement near joints are highly restrictive. Testing and quality-control procedures are rigorous.

The exterior-type adhesives for CERT EXT JNTS products are suitable for bonding structural end-jointed and laminated wood products for use in general construction where a high strength, waterproof adhesive bond is required.

WWPA Certified Exterior Joint Publication (PDF 88kb)

Advantages of using Finger-Jointed Lumber

• Stays straighter than solid-sawn dimensional lumber.
  • Less Crook.
  • Less Bow.
  • Less Twist.
• All lumber is surfaced dry.
• Can be used interchangeably with solid-sawn dimensional lumber of similar grade.

Mid-Columbia Lumber Products are engineered finger-jointed lumber made from a variety of dried Douglas Fir, White Fir, Hem/Fir and Spruce/Pine/Fir (SPF).

• Our material is S4S to precision accuracy with better alignment of edges resulting in minimized offsets and superior appearance.
• The material is specifically selected for individual customer’s needs in their particular market and application.
• Finished lengths of up to 40 feet are achieved by finger-jointing shorter pieces together.
• Available in 2x4, 2x6, 2x8, 2x10, and 2x12.
• The process of finger-jointing the lumber to achieve longer lengths delivers superior straightness, stability and consistent performance for demanding applications for industrial framing, including tall walls, trusses, concrete forms, beams, plates, posts, decking etc.
• Our product has all the advantages and attributes of solid wood - strength, nail holding, stiffness and durability.
• All material 20’ - 40’ is double end trimmed for accuracy.
• Precision end trimming available up 20 feet long.
• All material has certified exterior joints, all WWPA grade stamped “CERT EXT JNTS” on each end.

Technical Specifications

• Finger-jointed using 7/8” finger length for maximum gluing surface and strong joints. Phenol resourcinal formaldehyde adhesive for exterior quality joints.
• Finger-jointed using Western Wood Products Association Glued Lumber Products Procedures.
• 101.05 and the American Lumber Standards Glued Lumber Policy.
• Interchangeable with solid lumber of the same species and visual grades (American Forest & Paper Association -2005 National Design Specifications s.4.1.6).
• Design Values (bending, tension, compression, stiffness, nail holding) are the same as for solid lumber of the same species and grade.
• Tension tested for roof loading to 21 times design tension value for grade.
• Dunnage attached. Heavy duty wrap applied. Rail or truck delivery.