Engineered wood and frame-grade panels provide backbone for upholstered furniture
By Marilyn Thompson
January 18, 2017 | 1:54 pm CST

Design flexibility and cost-effectiveness without sacrificing indoor air quality: sustainable North American engineered wood products help make upholstered furniture manufacturing more efficient, economical, and compliant with formaldehyde regulations.

Wood is the product of choice when it comes to manufacturing furniture. Plywood has been used in furniture frames for many years. And as manufacturers continue to streamline and automate their assembly processes, frame-grade plywood and OSB and other engineered wood products are proving a reliable choice for furniture frames—not only for their strength, economy, and workability, but also for attributes like environmental value and indoor air quality. 
North American-produced plywood and OSB provide many advantages for manufacturers looking to select sustainable materials to use in their furniture. Many consumers are increasingly conscious of environmental impacts and are seeking out products that are sustainably produced. And with new governmental regulations for indoor air quality going into effect, it’s especially important to understand how furniture frame components can affect the air in the home. 

Frame-grade panels deliver quality, high yield, and low cost

North American wood structural panels and engineered wood products are sourced from sustainably managed North American forests that are growing more wood every day, supporting the manufacturers’ sustainability message. Not all imported wood products can make this claim. APA-trademarked frame-grade panels meeting U.S. Product Standards PS-1 and PS-2 have such low formaldehyde emission levels that they easily meet or are exempt from the world’s leading formaldehyde emission standards and regulations. 
On December 12, 2016, the EPA released their final rules for “The Formaldehyde Emission Standards for Composite Wood Products Act of 2010.” The final rule includes formaldehyde emission standards applicable to hardwood plywood, medium-density fiberboard, and particleboard, and finished goods containing these products that are sold, supplied, offered for sale, or manufactured in the U.S. With respect to the structural panels manufactured by APA members, the “formaldehyde act” is consistent with the Airborne Toxic Control Measure (ATCM) for composite wood issued by the California Air Resources Board because structural engineered wood products are exempted. 
The engineering and technology that goes into today’s engineered wood products mean that manufacturers can make more efficient use of the resource and gain more strength and value from less fiber. 
Manufacturers who make the switch from hardwood lumber to frame-grade wood structural panels for their upholstered furniture frames achieve higher material yields and reduced assembly costs. APA wood structural panels dramatically improve material yields and productivity when compared with solid wood stock. Manufacturers report that they have gone from a 30-40 percent yield with hardwood frame-grade lumber to a 90 percent yield with plywood.
Wood structural panels deliver quality furniture that will stand up to the rigors of years of use. Plywood and OSB panels eliminate the need for drying yards and dry kilns for frame stock, eliminate cutting and product waste due to defects, and eliminate planing to ensure a smooth surface. Most important, using large dimension plywood and OSB panels can optimize cutting schedules, particularly where Computer Numeric Control (CNC) routers are used. Furniture-grade panels are easily machined with CNC equipment, enhancing component accuracy and improving frame quality while speeding production and lowering manufacturing costs. CNC-machined panels expand design capabilities well beyond those of conventional, stick-built frames. Frame-grade panels are engineered for their intended end use, allowing the manufacturer to take advantage of their strength and fastener-holding capabilities. They can be cut into small parts without seriously degrading their structural performance. 
Panels are uniform and dimensionally stable, which makes them ideal for notched joints commonly used in furniture manufacturing. The manufacturer can eliminate problems with warping and crooked or bowed parts and depend on a consistent, dry moisture content. Consistency of wood structural panel components helps to reduce waste, provide more uniform quality, and thus increase customer satisfaction. 
As more furniture fabricators turned to wood structural panels in the past decade, wood panel manufacturers responded with the development of their own proprietary panels specifically manufactured for frame stock. Today, several factors contribute to the successful use of frame-grade panels in a wide range of upholstered furniture designs. These include: 
  • Frame-grade plywood and OSB panels are readily available and cost-competitive when compared with hardwood lumber. This gives the manufacturer more cost control with the finished product. 
  • Frame-grade panel properties, such as strength, fastener-holding capacity, consistency, dimensional stability, and workability, lend themselves well to the demands of quality furniture production. 
  • Panel size improves manufacturing efficiencies and allows state-of-the-art manufacturing technology, such as CNC panel saws and routers, to be used. 
  • High-yield production minimizes material waste, reduces cost, and benefits the environment. 

Selecting panels that meet the demands of upholstered furniture

Because the final dimensions of furniture parts and the anticipated loads are so different from those of construction, it’s important to use frame-grade panels that are designed for furniture manufacture. 
Typical plywood and OSB panels are designed for construction applications where uniform load conditions are the norm. In these applications, panels are usually used full size or cut into pieces no smaller than 24 inches wide. 
Furniture frame applications, however, require panels to be cut into parts, sometimes smaller than 6 inches wide. These narrow widths, coupled with loads imposed on frames in use, require the use of frame-grade plywood or OSB to avoid overstress due to concentrated loads being applied on very small areas. With furniture-grade panels, the manufacturer can realize a sturdier frame and significantly increase yield.

Key panel characteristics for good frame performance

In order to have good frame performance, manufacturers need to consider three key characteristics when selecting plywood and OSB panels: proper panel grade, ply/layup considerations, and thickness. 
  • Proper panel grade: Use a plywood or OSB panel grade that’s designed for the particular demands of furniture frames.
  • Ply/layup considerations: Special frame-grade panels allow the user to specify the number of plies and their arrangement within the panel. However, the composition of the panel should still match the requirements panels need to meet for structural integrity, strength or stiffness, ability to drill holes into the panel edge, and fastener-holding capability. Some companies find that parallel laminated center plies help improve the holding strength of edge fasteners and make drilling easier. 
  • Thickness: Individual frame parts must be thick enough to resist imposed loads. The frame design itself and connection details can significantly affect the required thickness of individual parts. Thicknesses typically range from 23/32 inch to 7/8 inch, but panels can be manufactured in custom layups and thicknesses up to 1-1/8 inch. 
Many manufacturers use different thicknesses in different parts of the frame. Other manufacturers prefer to use one thickness, such as 7/8 inch or 1 inch, throughout the frame. While this increases material costs, it also reduces inventory management costs and enhances frame quality. 
The optimum thickness of a given part also can be significantly affected by the overall frame design. Highly loaded parts, such as front rails, can be braced in a number of ways to reduce the thickness reached. Frame-grade panels can also be engineered to improve strength properties in the desired direction by changing the ply layup and grain orientation of inner plies.

Specifying panels for furniture frames

APA-trademarked frame-grade panels are proprietary products. Each APA member manufacturer determines the specific construction of their frame-grade panels to best meet the needs of their customer and the furniture industry. Unlike “off the shelf” panels, this allows a furniture manufacturer some input into the engineering of panels in order to meet their particular requirements. 
When ordering panels for furniture manufacturing, specify proprietary frame-grade panels manufactured according to the PS 1 or PS 2 Product Standards and the desired panel thickness. The manufacturers and their distributors can then help to determine the best panel to meet specific requirements. They may consider such things as species, veneer grades (for plywood orders), number of plies and ply layup requirements (for plywood orders), and panel density (for OSB orders). For additional information, visit

Have something to say? Share your thoughts with us in the comments below.