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.
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.
