SOLID WOOD OR VENEER? PLYWOOD OR MDF? ETC

Many people when choosing wood products ask which is better, solid wood or veneer? Plywood or mdf?
There is no simple answer. It’s a little like the question; which is better, aluminum or steel? It depends on the application.

Here are some definitions:

Solid wood – is just that, a tree cut into boards.

Veneer – in this context is solid wood, cut thin and glued to a substrate. The substrate might be plywood, mdf or particleboard.

Plywood – typically, plywood is made of layers of veneer about 1/8” thick glued together, alternating the grain direction of each layer.

Mdf – this definition is taken from the Industry Canada website.

Medium density fibreboard (MDF) is a non-structural panel made of wood fibres bound together with adhesives under heat and pressure. It can be made from a variety of natural fibres, yet wood is by far the most important because of its relative abundance and year-round availability. Mill residues and chips are the common feed stocks in existing fibreboard plants.
Wood is mechanically refined, and the panels are formed through a dry process. This uses less water than the wet process used for high density fibreboard (hardboard), with obvious environmental advantages, and it allows the production of thicker panels, as the wet process is limited to 12.5–mm (½–inch) thick panels.
MDF has a substantially homogeneous consistency resulting from the uniform distribution of the wood fibres throughout the board. Different characteristics can be produced to meet end use requirements. Smooth and solid edges can be easily machined and finished, and the uniform surface provides an excellent substrate for painting or applying decorative overlays.
This advantage has secured MDF's solid position in the furniture market. It has been successfully used in shelves, flush doors, television cabinets, wrapped moldings, cupboards, drawer fronts, table tops, pool tables, office furniture, plaques and shields, game boards, toys, picture frames, mirror surroundings, pedestals for tables, bedroom furniture and bathroom accessories. Thick MDF is penetrating markets for millwork applications such as door frames, window frames, window sills, stiles, casings and turnings, as a substitute for solid wood.

Here are some considerations, advantages and disadvantages of the different materials:

In the Industry Canada definition of mdf it is described as a non-structural panel. I believe this refers to construction and building applications rather than furniture. Mdf is suitable for all manner of cabinets and furniture but its strength as a beam is much less than solid wood or plywood. For example, a plywood or solid wood shelf supported only on its ends can be longer than one of mdf without sagging. Plywood is probably the most rigid material because the laminations increase its strength. Solid wood is more rigid than mdf but its rigidity will vary depending on the species.
The rigidity of the material will affect the design. In order for an mdf shelf to have the same rigidity of solid wood or plywood it will need to be thicker, if it is the same thickness it will need to be shorter.

One of the most significant differences between mdf, particle board and plywood is resistance to moisture. This can be a consideration when choosing material for applications such as lower kitchen cabinets. Typical melamine (particle board with a micro thin layer of melamine plastic laminated to it) is extremely vulnerable to any exposure to water. A leaking dishwasher will destroy this material in short order, whereas plywood is much less vulnerable.

Another important consideration is stability, expansion and contraction. Solid wood is the least stable option. As the relative humidity drops during the winter when the heat is on, solid wood shrinks. When the humidity rises during the summer, solid wood swells.
If wood products, especially doors are not designed and made to accommodate this reality, warping, cracking and other distortions may occur.
A typical example is a frame and panel door. In this case we have a solid wood frame with a raised solid wood panel. The arrows indicate the direction of the grain.



Solid wood expands and contracts across the grain, in this case perpendicular to the direction of the arrows. A log shrinks mostly in diameter rather than length when it dries.
Because the frame of the door is narrow in width, the expansion and contraction (movement) across the grain will be minimized. The panel, which is wider will move more but because it is “floating” within grooves in the frame, it is free to expand and contract without distortion.
A flat panel door made of solid wood, will expand and contract across the grain, depending on the type of wood and the size of the door the movement may be quite significant. And depending on the orientation of the annual rings in the wood to the surface, the door may also warp.

Another consideration is the cost. This can vary widely between these different materials.
For example, a table top 36” x 96” x ¾” made from a high quality ¾” maple faced plywood with 1/8” thick solid edging might cost about 100.00 for materials and about the same in labour, not including finishing.
The same table top made of solid maple might cost 200.00 for material and anywhere from 650.00 to 1000.00 in labour depending on the rates of the shop producing the work.
There are also aestetic considerations. The veneered table top will have a consistant look with one piece of veneer or matched slices of veneer. The solid wood top will be made of various boards probably coming from different trees.

In summary, it is best to approach the choice of materials with an open mind understanding that no one material, solid wood, veneer, plywood, mdf or particle board is inherently better than another. Each has its individual properties and characteristics.
If you are working with the right designer / maker / supplier or salesperson, they will help you make the right choice for your application.

Francis Lemieux www.francislemieux.com