Plywood: Properties, Characteristics, Types & Uses

A question I often get asked about plywood is how plywood gets manufactured. Plywood, of course, is not a solid thick sheet of wood derived from a single tree trunk but an engineered wood. It is the oldest type of engineered wood and consists of thin layers of materials or wood veneer plies glued together. Each ply gets placed over the other with wood grain rotated perpendicular to each other.  

As one of the engineered woods, plywood differs from Medium-density fireboard, Particle board, and Oriented strand board (OSB). It is a wood product derived not from a single tree but different trees. Moreover, its plies get bonded together using phenolic resin. To manufacture a sheet of plywood, manufacturers bind together at least three wood panels.

What is Plywood?

Plywood is a composite material of wood fiber sheets bonded together by resin. The grain alternation in plywood gets referred to as cross-graining, which offers several advantages. First, it lessens the wood’s tendency to split when you nail its edges. Moreover, it lessens shrinkage and expansion of the plywood for enhanced dimensional stability. It also improves the consistency of the plywood panel. 

Plywood manufacturers also follow an odd-number-of-plies scheme to enhance balance and reduce warping. For this reason, plywood offers remarkable stiffness relative to the surface ply’s grain direction. You will find some thinner plywood sheets with plies arranged at 90° angles to each ply, while you will also find high-quality plywood sheets designed with plies arranged in gradation of 45° angles relative to each other. This arrangement offers more enhanced strength at different points or axis.

Different Types of Plywood

If you are desirous of using plywood in your woodworking projects, it will be best to know the following different types of plywood so that you can select the plywood type best suited for your upcoming projects:

1) External Plywood and Internal Plywood

By its name, you will intuitively know that external plywood type is used for exterior surfaces, especially when you need an aesthetic or decorative finish. This plywood type is not designed to bear stress or loads. For example, it gets used for wall cladding and exterior wall surfaces.

On the other hand, internal plywood is designed for permanent structures that require high strength. You can use this plywood for ceilings, furniture, and wall paneling.

2) Structural Plywood

Structural plywood gets used for building permanent structures that require high strength. This plywood type is perfect for beams, flooring, bracing panels, and formworks. This plywood gets usually manufactured from hardwood or softwood.

3) Marine Plywood

Another type of plywood is marine plywood. This plywood gets specially treated with preservatives, varnish, or paint, and it gets designed to resist moisture and water damage. You can use this plywood for applications requiring resistance to fungal attacks and water damage like shipbuilding. Besides, this plywood doesn’t delaminate. 

The Different Grades of Plywood

Plywood sheets get graded according to discolorations, strength, resistance to moisture, surface defects, type of wood, surface veneer’s quality, and adhesive strength. These ratings will help you figure out the applications of the plywood. These grades come in letters like A, B, C, D, and N. 

D-grade plywood exhibits surface defects like knotting and graining. N-grade, on the other hand, has a few flaws. You will also find Interior C-D, which means its face is graded C, while its back is graded D. This grade indicates that this plywood is suitable for interior applications. 

Plywood Characteristics and Properties

Aside from understanding the different grades of plywood, it will be best likewise to be cognizant of the following characteristics and properties of plywood if you intend to use it:

High Strength

Compared to solid wood, plywood features almost the same structural strength as the solid wood from which it got derived. Depending on its laminated design, it additionally gains other properties. Remember that the veneer’s grains are at ninety degrees relative to the following ply. This makes the plywood sheet highly split-resistant, especially when you nail it at its edges. 

This arrangement renders the plywood sheet a consistent and uniform strength. Moreover, plywood sheets exhibit a higher strength-weight ratio when compared to sawn lumber. Thus, it is perfect for webbed beams. It gets also recommended for shear walls and flooring. 

High Panel Shears

Plywood’s layers or plies also exhibit an odd number scheme for enhanced bending strength. Thus, some high-quality plywood sheets have varying veneer grain arrangements instead of the usual 90-degree arrangement. 

Typical angle arrangements consist of 45-degree and 30-degree setups. These variations in angle provide enhanced strength. Thus, with these ply arrangements, plywood can be used for securing panels and other applications.

Excellent Flexibility

Plywood also allows for ease of shaping. Manufacturers can vary its thickness from three-eighths to three-quarters of an inch or several inches thick. Besides, manufacturers can quickly bond additional veneer layers to increase the thickness and strength of plywood sheets. Thus, plywood is indeed a very flexible material for many woodworking applications and projects.

Highly Resistant to Impact

Plywood exhibits incredible tensile strength because its panels are cross-laminated. This way, the stress or force gets distributed over the whole surface of the plywood. This, in turn, lessens the tensile stress on plywood. 

So, even if you load plywood with enough stress, it doesn’t break even if the load is twice its expected load. This property comes in handy even during high winds and high seismic activities. 

Quite Resistant to Moisture

We could not say that not all plywood sheets are resistant to moisture. But if you’re using marine plywood, you can expect it to be highly resistant to moisture and water. Nevertheless, the level of moisture resistance of plywood depends on the glues used to bind the plies, the type of paint, and the varnish you use to finish it. Here is the guide on painting plywood wall.

You can use moisture-resistant plywood for sheds, cladding, and marine construction. You should also go for cross-laminated plywood to ensure your veneer will not expand or shrink if you use it for floors and walls. 

Relatively Fire Resistant

Plywood has long been known for being a fire hazard. Thus, several plywood manufacturers have been working to produce plywood sheets that are highly resistant to fire. They do this by adding a chemical coating to plywood to increase its fire resistance and by combining fibrous cement and plasterboard to the firewood structure. This way, your use of plywood will comply with your neighborhood’s regulations. 

Insulating Property

Plywood exhibits high insulation properties. It can insulate a place from cold and heat and act as a sound insulator. Thus, it gets typically used for soundproofing and insulating rooms. Using plywood, you can insulate your floors, ceilings, roofs, and walls. 

Resistant to Chemicals

Plywood may be susceptible to the effects of chemicals. Nevertheless, treating it with preservatives can make it impervious to these effects. When adequately treated, plywood can be utilized even for cooling towers and other applications requiring chemical resistance.

Applications and Uses of Plywood

Once you’ve known the succinct properties of plywood, the next thing to figure out is its applications. Below is a rundown of the list of applications and uses of plywood:

General Purposes

Even if you haven’t dabbled yet in woodworking, you might have used plywood in your lifetime. This is because plywood is such a versatile material for many applications. Besides, it is an excellent building material for both indoors and outdoors. 

You can use it to make furniture, cabinets, and tables, expecting the results to be durable. You can also use it for general construction, including marine and framing applications. 

Its remarkable mechanical property makes it an indispensable material for buildings. It gets also utilized as a structural material in façade panels. Moreover, you can carve plywood and bend it into desired shapes. 

Exterior Wall Sheathing

You can use plywood for exterior wall sheathing. In North America, for example, a typical wall construction of a home consists of using a 2′ x 4′ or 2′ x 6′ frame skinned using plywood sheathing (exterior grade). These plywood panels are fastened to studs to prevent horizontal and vertical shifting and to add strength. Moreover, this construction technique protects the structure from high wind and seismic activities like earthquakes. 

Interior Walls

You can also use specific plywood types to frame the interior stud walls or wood paneling. You will not see these plywood panels after the final finish, though you can also use A-grade sheets of plywood that you can paint or stain for an excellent look and finish. 

Flooring and Roofing

You can use plywood sheets for sheathing roofs. They could serve as suitable and durable skin before laying metal, membrane, or tiles. Besides, you can use plywood sheets as subfloors. Some plywood panels, for example, include edges with tongue and groove designs that you can shiplap to distribute the load and stress without shifting or moving. 

Furniture Making

Plywood, of course, is a practical option when it comes to making furniture. It is also a cost-effective option. You can use high-grade plywood if it is required to have a nice-looking one side. Then, you can use other plywood grades for the different components of the furniture. 

Plywood is such a versatile and flexible material. So, you will typically find furniture like wardrobes, dressers, media centers, bookcases, shelves, and console tables made of plywood. 

Cabinet Making

As mentioned above, you can use plywood for making different types of cabinets. You can use it for making kitchen cabinets, bedroom cabinets, etc. You can use high-grade plywood for backs and sides, while you can use lower grade for the interior of the cabinet. 

It will be good to note that plywood is far better than MDF and traditional chipboard. Besides, it is more durable. 

Frequently Asked Questions on Plywood

Now that you know the different plywood applications, you might still have questions about plywood. If you still have questions about plywood, it will be best to be cognizant of the following FAQs about plywood, for they might also be the questions playing on in your mind:

Is Plywood Better Than Other Wood Materials?

Plywood is often the choice product for many projects by woodworkers. Because of its remarkable properties, many love to use plywood for their woodworking projects. Compared to Oriented strand board, however, plywood appears to be lighter and stiffer. Besides, it retains water less than OSB. Nevertheless, both materials are similar to each other in many aspects. 

Compared to MDF, however, plywood is a bit weaker than MDF. MDF would be better if you intend to use it for shelves. Plywood also has visible grain lines, while MDF is made of materials from solid wood. Plywood, however, is more costly than MDF. Furthermore, plywood is easier to cut smoothly than MDF. Besides, MDF produces much dust when cut. 

Is Plywood Not Rot Resistant?

Plywood, in itself, is not rot resistant, although you can buy plywood with high resistance to decay. Nonetheless, you can treat plywood with chemicals to make it more rot-resistant. Moreover, plywood has a certain tolerance for water, primarily if you use marine plywood. Besides, it will shrink back to its original size as it dries. 

Some plywood types are decay-resistant treated. These plywood sheets, of course, will provide long-term resistance to decay and insect attacks. You can also use Chromate Copper Arsenate to improve the resistance of plywood to decay.

Conclusion

Plywood seems to many to be a relatively recent invention of humans. However, its use dates back to ancient times in Ancient Egypt, for Egyptians already made use of plies of wood and bonded them together. However, modern plywood dates back to the 18th century. 

Plywood is one of the best materials you can use for your woodworking projects. It is lightweight compared to other building materials. It has many good properties, making it a go-to material for many woodworking projects. Besides, you got many size and thickness options when you opt for plywood. With proper treatment, you can make plywood last for many years.