The History and Importance of Engineered Wood in Green Building

A level of strength that equals steel or solid timber gives glulam (glue laminated timber) products construction capabilities that environmentally conscious builders and homeowners may choose to consider. The combination of strands of wood, lower grade logs, veneers and other wood elements creates powerful structural members for applications such as headers and studs, joists, girders and columns. The process of bonding multiple laminated layers to develop glulam products produces structural supports of varying depths, lengths and curvature that prevent the unnecessary destruction of natural forests. 

Contributing to the Welfare of the Planet 

Responsible choices of construction materials give builders and homeowners a role in actively participating in protecting the planet. The development of sustainable construction materials such as glulam promotes environmental efficiency while delivering a superior product. Architecture and Design points out that the many layers of laminates eliminate “strength-reducing characteristics” of natural wood to produce materials that have more strength than solid timber. The manufacturing process offers access to creative and innovative building concepts that require “larger and longer members” than traditional “solid sawn timber” can provide. An initial decision to use sustainable building materials creates a positive effect on the environment and the planet.

Creating Versatile Plywood

Plywood is widely regarded as the first ‘engineered wood’, and its layers of veneers created a highly usable product that provides strength and stiffness. The general idea behind larger glulam members and beams is the same as plywood, but creates an engineered product that improves on plywood by bonding larger pieces end-to-end to form a highly durable, face-bonded straight or curved construction material. The Engineered Wood Association (EWA) honors the American Plywood Association, its predecessor, by continuing to use APA as part of its ID. Douglas Fir Plywood developed the technology that made the product an essential construction element for door panels and automobile running boards in the 1920s.

World War II produced a demand for plywood barracks, PT boats, gliders, assault boats, machinery crates, Seabee huts and lifeboats. After the war, a booming economy relied on the industry to produce 4 billion square feet of plywood by 1954. The Douglas Fir Plywood company later became the APA to reflect its acceptance nationally. A similar transition from the production of plywood to glulam products allows APA-Engineered Wood Association to inform builders and homeowners of the comprehensive line of building materials on the market today.

Advancing to Complex Engineered Wood Products

Glue laminating got a start in Europe at the end of the 19th century with a Swiss patent that introduced the concept of glued laminated timber for construction purposes. The development of an entirely water-resistant adhesive that protected glulam from the elements led to a publication of manufacturing standards by the U.S. Department of Commerce. The entrance of glulam into the market signaled the availability of improved product performance and better design values at competitive prices for homes and commercial projects. Homes achieve benefits from simple materials such as headers and beams while architectural feats of domed roofs with spans of 500 feet incorporate remarkable innovations. Classifications by usage categories of premium, architectural, framing and industrial offer choices that match any project. The engineered product makes vaulted designs possible in churches and public buildings as well as homes that feature open spaces. 

Its strength and versatility make it perform well in numerous applications that include garage door headers and purlins as well as floor, ridge and cantilevered beams, decking, bracing and columns. In commercial projects, contractors use glulam for simple flat roofs and complicated expansive arches. Some of glulam's many advantages include the practical purposes that the Balance Small Business recommends for its green qualities of low formaldehyde levels and reduced weight that decreases transportation costs. The natural materials that comprise glulam come from “well-managed forests” that protect the health of the planet.


Builders use I-joists in residential roof and floor construction for their ability to cover long or short spans. Their straight and true characteristics allow builders to achieve a level framing surface and avoid crowning. They perform well in commercial applications where architects specify long spans or heavy loads that get maximum performance from straight or curved beams, radial or Tudor arches and pitched or curved beams. The Construction Specifier points to some features of I-joists that make them suited explicitly for construction projects such as their “greater dimensional consistency” as well as a load-bearing ability that exceeds that of traditional lumber. 

With lengths of more than 50 feet and thicknesses up to 3.5 inches for individual pieces, glulam enables manufacturers to produce thicker beams to span longer distances and support heavier loads by bonding them together. From an environmental standpoint, builders and homeowners can appreciate the benefits of using I-joists that contain “less wood fiber than solid sawn lumber,” according to Construction and Equipment. The difference amounts to 36 percent for 16-inch on center spacing and 46 percent for 19.2 inches on center.

Rim Board

As a construction element that provides an essential function around the perimeter of a residence, rim board makes its presence known only during the building phase. APA describes it as a structural component that fills the space between the top and bottom plates of wall sections in homes that have two floors. For single floor homes, it fills in the space between the sill and bottom plate. It provides the attachment point for floor joists and without it, an open space exists that allows moisture and debris to accumulate within the structure. The strength, precision and reliability of the APA rim board allows it to provide a fit between the floor and the foundation that matches the depth of the companion wood I-joist. It offers an advantage over traditional solid sawn lumber that becomes impractical when it does not match the size of the engineered I-joists.