Materials used in furniture for todays markets range from "solid woods" and plywood or veneered woods to engineered wood products. Some are well designed and others are not. There is quite an array of composite products both in the RTA (ready to assemble) and finished furniture markets. They can be broken down into approximately 3 groups: veneer wood, high density laminate (HDL), and paper or low density laminates - all faced onto composite cores, either on one or both sides of the core.

Composites need to be explained first. There are three basic core types that have steadily replaced plywood and solid wood construction - chipboard, MDF and strawboard. Plywood is the original engineered wood panel product, made from glued, cross-lapped veneer peeled from softwood logs.

Chipboard, also called particleboard, is a pressed collection of wood chips, usually bonded with UF (urea-formaldehyde) or other thermoset resin such as MF (melamine-formaldehyde) and PF (phenol-formaldehyde). Of these three resins, UF is most noted for releasing formaldehyde and is also weakened if it gets wet or damp. If this concerns you, remember that the walls and roof of your home are constructed with the same materials.  There is limited use of non-formaldehyde resins, based on urethanes or isocyanurates (usually referred to as MDI), in composites, but they are much more expensive. There are 4 grades of particleboard: M1 (the poorest), MS, M2 and M3, with most RTA products using the two middle grades. In many instances it hard to test for real world differences between the two middle grades and in my opinion they lack in edge strength to hold screws. The coarsest type of "chipboard" is OSB (orientated strand board), commonly sold as replacement for plywood stock at lumberyards.

MDF (medium density fiberboard) is a heavily pressed collection of wood fibers, also bonded with a minimal amount of thermosetting resin. This product is very dense at around 45-to-60 lbs/cubic ft and has a uniform brown color. It can be cleanly cut, edge machined and drilled, unlike most chipboard designs. Common hardboard is the typical ~1/4" brown pressed backing found on bookcases and as perforated panels for suspending metal hangers. Hardboard is a thin, high density cousin of MDF at around 60-to-70 lbs/cubic ft. Because it is thin and stiff, hardboard is easily fractured if bent. A common tradename often associated with hardboard is "Masonite".

Strawboard is a pressed collection, of yes, straw; usually wheat straw, the largest cereal crop residual on the planet. Canadian strawboard tends to be tighter and more uniform than many chipboards. Both chipboard and strawboard is pressed to different densities and use different amounts of thermoset resin. Low density and/or low resin use in such designs make them weaker and more subject to damage. Due to the waxy and hard-to-bond nature of straw sources, the board is often bonded with a better quality resin than typical UF.

More imported products are appearing with other pressed wood or vegetable fiber composite cores. Strawboard uses vegetable fiber, which simply means "non-tree" fibers like flax (raw low-quality linen, the linseed oil crop residual), coir (coconut husk), bagasse (sugar cane stalk residual), kenaf or jute. Hemp can be misleading because there are tropical tree varieties like abaca (which is a leaf fiber from the banana family) as well as the much-discussed and notorious northern bush varieties which are stalk fiber. Maize (corn stalk) fiber remains difficult to process due to fluffy and weak pith fiber.

Wood fiber basically comes in two flavors, softwoods such as pine or fir and hardwoods such as oak and maple. The thousands of species of bamboo are yet another source for pressed products. Bamboo, often the Moso species, has been incorrectly touted as harder than traditional woods. Its known levels of naturally occuring silica are internally bound, not found on the surface where hardness counts. Rice straw has significantly higher levels of natural silica, which does nothing for its "hardness". Wood hardness is dramatically masked or enhanced by any subsequent resin coating used.

The strength and durability of an engineered wood product is based on both it's core and its surfaces. Wood veneer and HDL provide the strongest surfaces and HDL is extremely resistant to impact. HDL is constructed of layers of resin-saturated paper that is pressed into a tough, plastic-like, thin composite. Most commodity kitchen counter tops are covered with HDL, which also has good heat resistance.

Paper and low density laminates provide the least durable surface and contribute nothing to the overall product strength. Low density laminates are a few layers of paper impregnated and/or coated to improve durability.

Paper-faced flooring is a different matter. This paper is coated with an amorphous silica to function as a top wear surface. Depending on the amount of silica and the bonding of the coating or multiple coatings, the surface wears (abrades) better than wood due to its surface hardness. Hardness is not always of value if a surface is gouged or cut. This is reflected in the wide range of warranties provided for these flooring systems (p.s. - always read the fine print and try to find out how many coatings layers are applied, more layers are usually better than less). Typically, an MDF core is used in these constructions. I prefer traditional hardwood flooring, but these engineered wood floor planks are easier to install.

Plastic-wood composites, formed by mixing wood fiber and polyolefins, are extruded products not yet found in furniture but are making inroads in exterior decking, railing and fencing components. These products are undergoing changes in design to balance properties such weatherproofing and non-sag while retaining other "woodlike" properties. There are some extruded interior finishing trimboards made with this technology.

Fiber-cement board is another exterior and wet location product made by mixing wood fiber and cement. With the correct fiber content it handles much like wood. Like plastic-wood, it has not yet found commercial use in furniture applications.

The reason I prefer solid woods and plywood core veneers is for maintenance and lifetime. Once a composite core gets wet, it swells, loses strength and rarely returns to its original shape. If a composite product gets hit hard enough or gouged to show damage through the facing, you have few recourses for repair.Wood can be spot swollen with water and then sanded/stained back to a more reasonable appearance. Unless the composite core is very dense, tight and well bonded with resin, the particulate core eventually loses nail and screw "grip" due to vibrations with time. This can also happen with wood, but to a lesser extent AND wood holes can be reinforced and reglued.

Solid wood (and plywood to a lesser extent) have a major but poorly understood advantage over composites. No composite survives edge impacts very well, though they can be designed to survive (flat) surface impacts. Edge impacts often crumple or shatter a wood composite. This is nearly impossible to repair. Some manufacturers, perhaps realizing this problem, attach solid wood edging which can function as a "bumper".

The poorest overall construction is a paper-surfaced core of low density, large chip, chipboard having a low resin content. This construction will not survive impacts, crumbles and cracks easily and does not survive humid environments. A classic example is to see a shelf or top surface sag or curl badly with age, especially in a basement or other humid location. You cannot repair the surface. You cannot securely nail or screw into it. Special fasteners are needed in constructing furniture.

WHAT TO WATCH OUT FOR.....

Pull out a shelf or look on the reverse (wall side) of the furniture to inspect the construction. If a table is a split top design, open it and look at the mating edges.Can you rub off particles with just thumb pressure? Ignore dust on the edges, because that may be due to cutting the composite when it was fabricated into the finished product. Are particles sizes generally >1/8" and/or are there numerous air gaps in the cross section of the pressed composite? If yes, I would avoid this product.

If the facing on the particleboard shelf looks paperthin I don't recommend this constuction in bathrooms or basements. In a few years, depending on direct moisture or relative humidity, the product will swell, blister or flake and otherwise lose strength. Most thin paper facers have poor abrasion resistance and will scuff with regular use. Occasional furniture using paper facings printed to look like wood will not take well to any impacts or heavy scratches.

The best overall construction is a HDL- or wood veneer-surfaced core of MDF or densely-packed strawboard or very fine chipboard. MDF can be drilled and cleanly cut and is very rigid. It is often used in stair construction because of these properties. This construction can use normal nails or screws, however HDL must be predrilled before nailing. My preferance remains solid wood or plywood, but keep in mind the benefits of a well-designed engineered wood:

1.) more of the tree (or even non-tree) fiber is utilized; solid wood wastes the most when utilizing a tree and veneers less so, but more of a tree can be chipped, processed and not left to waste

2.) MDF and HDL components can often out-perform wood in specific properties such as stiffness or impact strength or dimensional stability.

3.) engineered woods can be constructed to longer and wider dimensions than solid wood, unless you deal with glued constructions