Engineered Wood

Plywood is made up of glued layers of thin wood sheets arranged with opposing grain directions. This makes the sheets stiff, flat, and dimensionally stable. Within this broad category, there are near infinite variations of species, thickness, rating, veneers, etc. to suit a range of different circumstances: interior, exterior, construction, furniture, formwork, etc. Plywood needs at least three plies (and always an odd number). Although specialty plywood can have any number of plies above three, most plywood is categorized as 3-ply, 5-ply or multi-ply. Plywood is also graded into 4 categories: A, B, C and D. The grade refers to the quality and appearance of the plywood’s face and back veneers. A has the highest quality and is the most expensive, and D is the least expensive. 

Birch Plywood is one term for a type of plywood that has lots of thin layers and almost no voids. It is flatter, stronger, and stiffer than most other plywoods, and it is often chosen for applications where the edges will show (rather than get covered with edge banding or other surface treatments). The lack of voids makes it ideal for laser cutting–less risk of catching on fire. It is also well suited for CNC routing, due to its flatness. 

Plywood sheathing or structural plywood is intended for permanent structures. It is strong and inexpensive, but unfinished, and therefore not suitable for places where it will show. It is usually covered by other types of materials. Use plywood sheathing for framing, beams, flooring and bracing panels.

Furniture grade plywood is often faced with thin veneers of more expensive and beautiful species of wood. Common options include walnut, cherry, and oak. They can give the appearance of solid wood panels. 

MDF is composed of wood-mill byproducts, primarily sawdust and wood shavings, which are ground into a fine powder, dried to remove moisture, and then mixed with resins and wax before being pressed into panels. Pros: it is inexpensive, flat and smooth, and paints well. Cons: it is heavy, has poor tensile strength and tends to sag, swells when wet, and typically includes urea-formaldehyde glue. Formaldehyde is a carcinogen and may also cause allergy, eye and lung irritation when cutting and sanding.

Like MDF, hardboard is composed of wood fibers that have been processed and compressed into sheets. It is typically available in ¼” or ⅛” thick sheets, and it has a smooth, shiny side and a textured side. 

Particleboard combines sawmill waste, such as chips and sawdust, with synthetic resins to form panels. It is not as strong as plywood, but its low cost makes it a good choice for sheathing, cabinet construction, flooring, etc. 

Melamine is a type of laminate that can be applied to particleboard, plywood, or MDF. It can be found in a variety of colors, patterns, sizes, and thicknesses. The laminate is durable, scratch-resistant, waterproof, stain-resistant, and easy to clean.

OSB is made from compressed layers of wood strands or flakes bonded with adhesives. These longer shards of wood make OSB stronger than particleboard. It is commonly used for roof sheathing, subflooring, and walls.

Fiber board is a cellulose-based fiber wall board. Similar in composition to paper mache, it is made from recycled paper that is compressed under high temperature and pressure. Homasote contains no adhesives. It is most often used for sound reduction and insulation. 

MDO is waterproof plywood suitable for outdoor use or anywhere that it might be subjected to moisture. The plies are glued together with waterproof resin, and the overlay coating on the faces is made from resin-impregnated fiber. The smooth face is ideal for painting. MDO is often referred to as signboard, since it is commonly used for outdoor signs. 

Fabricated by a process similar to plywood, LVL boards are thick enough to substitute for dimensional lumber like 2x4s. LVL boards are used for I-joists, headers, rim boards, beams and trusses. They’re also found in skateboards and truck bed liners.