Plywood is a composite material, although we often consider it as a traditional working material. It is composed of individual plies / veneers of wood. It is very strong due to the way the plies are put together. The grain of each ply is positioned at ninety degrees to the pieces of ply above and below it. The plies are glued together with synthetic resin, making a very strong composite material. Furthermore, plywood is usually constructed so that an odd number of plies are used. Plywood is less likely to warp or split, due to this construction.
Manmade boards of this type are supplied in a range of sizes and thicknesses. This is an advantage compared to natural woods, as manmade boards can be manufactured so that they are extremely wide. This makes plywood a popular material in the construction industry.

Softwood ply tends to be used in the construction industry for walls, roofs and floors.
Hardwood ply tends to be used quality laminate flooring, kitchen units and some furniture.
Marine plywood is used in boat hull construction. It is specially treated so that it is water resistant .

Plywood offers several advantages that make it a popular material in various industries. Here are some of its key benefits:

1. Strength and Durability: Plywood is made by gluing layers of wood veneers with their grains at right angles. This cross-grain structure gives it high strength and resistance to warping, cracking, or splitting.

2. Lightweight: Despite its strength, plywood is relatively lightweight, making it easy to handle and work with, especially in construction and furniture-making.

3. Versatility: Plywood comes in a wide range of sizes, thicknesses, and grades, making it suitable for various applications, from roofing and flooring to furniture and even boat building.

4. Cost-Effective: Compared to solid wood, plywood is generally more affordable, while still offering good quality and performance.

5. Wide Availability: It is widely available and can be manufactured in large sizes, unlike natural wood, which is limited by the dimensions of the tree.

6. Resistance to Shrinking and Swelling: Plywood is less prone to dimensional changes due to humidity or temperature variations, making it more stable than solid wood.

7. Sustainability: As it uses thin layers of wood, plywood maximizes the use of timber, making it an efficient and relatively eco-friendly option compared to some materials.

8. Aesthetic Appeal: Plywood has a natural wood finish, making it attractive for decorative purposes when used in furniture or panelling.

Plywood, while versatile and widely used, does have some disadvantages:

1. Cost: Compared to some other engineered wood products, plywood can be relatively expensive, especially high-grade or specialty types like marine plywood.

2. Moisture Sensitivity: Standard plywood can be vulnerable to water damage and may swell or delaminate if exposed to excessive moisture, unless it is a water-resistant variety.

3. Weight: Although lighter than solid wood, plywood can still be relatively heavy, especially in thicker panels, which may make handling and transportation challenging.

4. Splintering: The edges of plywood can splinter during cutting or machining, requiring proper tools and techniques to minimize damage.

5. Surface Appearance: Lower-grade plywood may have visible knots or grain irregularities, which might not be suitable for applications requiring a smooth or decorative finish.

6. Void Issues: In lower-quality plywood, there may be voids or gaps within the internal layers, which can affect its strength and structural integrity.

7. Formaldehyde Emissions: The adhesives used in some types of plywood can release formaldehyde, which may raise concerns about indoor air quality and environmental safety.

8. Limited Durability in Harsh Conditions: Plywood may not perform as well as some alternatives (like solid wood or composite materials) in extremely harsh or demanding environments.

Despite these drawbacks, plywood remains a popular choice due to its balance of strength, versatility, and cost-effectiveness for many applications.

During World War Two, the de Havilland Mosquito was called the "Wooden Wonder," because it was made largely from plywood. The Mosquito had various roles, including as a bomber, fighter and reconnaissance aircraft. Its plywood construction was a key factor in its success.
The fuselage was a monocoque design, constructed from two moulded plywood halves, bonded together. The wings were manufactured with two plywood layers with a central layer of balsa wood, which gave added rigidity and lightness. The tailplane and control surfaces were skilfully made from plywood and added to the aircraft's lightweight and aerodynamic efficiency.

An added advantage was that it did not require important metals like aluminum, which were in short supply.

Plywood is a versatile material and it has a wide variety of practical applications, because of its strength, durability and ability to be manufactured in large sizes.

1. Construction
Walls, floors, and roofs in building construction.
Sub-floors and underlayment for added structural support.
Scaffolding and temporary structures.

2. Furniture
Cabinets, shelves and wardrobes.
Tabletops, chairs and other pieces requiring durability.

3. Interior Design
Decorative wall panels and partitions.
Ceiling treatments for aesthetics and acoustic purposes.

4. Marine Use
Marine plywood is treated so that it is water resistant. It is used in boat hulls and docks.

5. Packaging
Crates and shipping boxes due to its lightweight yet sturdy nature.

6. DIY Projects
Crafts, custom furniture and home improvement tasks.

7. Flooring
As the base for laminate or vinyl flooring.
Hardwood plywood is used in quality laminate flooring designs.

8. Vehicle and Aircraft
Panels for interior finishes in vehicles and aircraft, due to its light weight.

Plywoods unique construction, with alternating grain directions, reduces the risk of warping or splitting, making plywood a reliable material for a wide range of applications.