Historically, plywood was one of the earliest engineered-timber products. By bonding together cut pieces of wood, a composite product was achieved that was bigger, stronger, and more rigid than the sum of its components. Cross-laminating sheets of timber veneer results in upgrading the structural advantages of the composite by spreading the with-grain strength of timber in both directions.
Plywood is much older than 1865 when it was first patented. Archaeologists discovered vestiges of laminated wood in Egyptian pharaonic tombs. The Chinese peeled timber and glued it 1000 years ago to make furniture. French, English and Russian artisans had versions of plywood as early as the 17th and 18th centuries. Early modern ply’s were created from very attractive hardwoods and used for doors, cabinets, desk tops, and chests but the softwood ply’s manufactured for construction which we see today are a 20th century product.
Gustav Carlson, of the Portland Manufacturing Company which produced wooden boxes, was invited to enter exhibits for a World’s Fair hosted by the City in 1905. His exhibits were wooden laminates made from Pacific Northwest softwoods. He spread glue with paint brushes and pressed the panels with house-jacks. Several of his panels were displayed under the title, “3-ply veneer work”. Several visitors to the fair took a great interest, placing orders for doors, cabinets and trunks. Within two years Portland Manufacturing had an automatic glue spreader and was operating a sectional hand press to produce 420 panels a day. The infant industry grew into today’s massive production units.
In 1934 the first waterproof adhesives became available which made plywood a viable alternative for automobile running-boards. When the precursor to today’s APA (American Plywood Association), the Douglas Fir Plywood Association was instituted, plywood manufacture became standardised by 1938, enabling quality control across manufacturers. As 1939 hove into view plywood became an essential war material with industry mills manufacturing 1.8 billion sqft annually during WWII. It was used for building barracks, PT boats, reconnaissance gliders, assault boats and more. US production by 1975 surpassed 16 billion sqft.
Marine ply’s are specifically designed for structural strength with greater impact resistance, and absorbs the effects of water movement and pressure. Marine ply’s are manufactured to the highest standards and both ply faces are made from A-grade veneers which are defect-free. An added bonus [In some circumstances] is they are usually free of toxins and preservatives since they rely on the natural durability and resins encapsulated in the product.
Today plywood is ubiquitous and used in all kinds of applications. It can be treated to various degrees (see our previous blog on timber treatments) to allow use in specific situations, or untreated for indoor and outdoor use. Renovation Warehouse can help you determine what ply you need for the job you have in mind.