Among the many types of plywood, CDX plywood is one of the most popular in commercial building projects.
CDX Plywood is among the most budget friendly plywood.
What is CDX Plywood?
CDX plywood is a type of softwood plywood that is commonly used in construction and woodworking. The term “CDX” stands for “C-D Exposure,” where “C” represents the grade of the front face veneer and “D” represents the grade of the back face veneer.
The “CDX” grading is composed of two parts: “C” and “D.” These letters represent the quality of the wood veneers on the front and back faces of the plywood, respectively.
- C Grade Front Face: The “C” grade refers to the front face of the plywood, which is the side that will be visible after installation. This veneer is typically of higher quality, with fewer knots, blemishes, or imperfections. It may have a smoother and more aesthetically pleasing appearance.
- D Grade Back Face: The “D” grade refers to the back face of the plywood, which is the side that will not be visible once the plywood is installed. This veneer may have more knots, grain irregularities, and other imperfections compared to the front face.
The term “Exposure” in CDX plywood indicates that this type of plywood is suitable for exterior applications where the wood will be exposed to various weather conditions.
In other words, CDX plywood is designed to withstand the elements, such as rain, snow, sunlight, and temperature fluctuations, without significantly deteriorating.
How is CDX Plywood made?
CDX plywood is made through a manufacturing process that involves layering thin sheets of wood veneer and bonding them together with adhesive.
Here’s a step-by-step overview of how CDX plywood is typically produced:
- Log Selection and Debarking: The process begins with the selection of logs, which are often softwood species like pine or fir. The logs are debarked to remove the outer layer of bark and prepare them for processing.
- Peeling: The debarked logs are then rotated against a cutting blade called a veneer lathe. This lathe peels off thin layers or “plies” of wood from the log. These wood veneer sheets are typically very thin, often around 1/8 to 1/4 of an inch (3 to 6 mm) in thickness.
- Drying: The freshly cut veneer sheets are dried to reduce their moisture content. Proper drying is crucial to prevent warping, cracking, or other issues that might arise from uneven moisture levels.
- Grading: The dried veneer sheets are sorted and graded based on their quality and appearance. The highest quality sheets with fewer knots, defects, and blemishes are often designated for the front face (C grade), while sheets with more imperfections are used for the back face (D grade).
- Layering and Gluing: The graded veneer sheets are then layered one on top of the other, with the grain direction of each layer perpendicular to the adjacent ones. This cross-grain construction provides strength and stability to the plywood. The layers are bonded together using a strong adhesive, typically a type of phenol-formaldehyde resin.
- Pressing and Curing: The layered veneers, along with the adhesive, are subjected to high pressure and heat in a hydraulic press. This process ensures a strong bond between the layers and cures the adhesive, creating a solid composite panel.
- Sizing and Trimming: The pressed panel is trimmed to the desired dimensions, resulting in a sheet of CDX plywood. The sheet is typically 4 feet by 8 feet in size, although other dimensions may also be available.
- Finishing: CDX plywood is usually not subjected to extensive finishing processes since it is often used for structural and exterior applications. However, the edges of the plywood may be sanded or squared off to improve uniformity and ease of installation.
- Quality Control and Packaging: The finished CDX plywood sheets are inspected for quality, including checking the bond strength, veneer alignment, and overall appearance. Sheets that meet the desired standards are packaged and prepared for distribution to construction sites, retailers, or other end users.
What is CDX Plywood used for
The cross-grain construction in CDX plywood adds strength and stability to the plywood, making it suitable for a variety of structural and non-structural applications.
For this reason, CDX plywood is commonly used for a variety of construction and woodworking applications, primarily in situations where its strength, durability, and resistance to the elements are important.
Here are some common uses for CDX plywood:
Roof Sheathing:
CDX plywood is often used as roof sheathing, providing a stable and solid base for roofing materials such as shingles. It helps distribute the load of the roofing materials and provides structural support to the roof.
Roof sheathing is a crucial component of a roofing system. It consists of panels or sheets of material that are attached to the roof framing (rafters or trusses) to create a strong and stable base for the roof covering materials, such as shingles, tiles, or metal roofing.
Roof sheathing serves as a secure surface for attaching the roof covering materials, such as shingles or tiles.
Proper attachment is essential to ensure that the roof covering remains in place and provides effective weather protection.
Read our guide on why CDX plywood makes a good roof sheathing material.
Wall Sheathing:
CDX plywood is used as wall sheathing in both residential and commercial construction.
It serves as a structural element that adds rigidity to the building’s framework, helping to withstand wind loads and providing a base for siding materials.
Subflooring:
CDX plywood is commonly used as a subflooring material over floor joists.
It creates a flat and even surface for the finish flooring materials, such as hardwood, laminate, or tile, while also providing structural support.
Exterior Siding:
While not the most common choice for exterior siding, CDX plywood can be used as a base layer for certain types of siding materials. It provides a stable surface for attaching siding panels or boards.
The plywood’s dimensional stability and uniformity helps in ensuring that the siding materials are securely anchored and aligned.
By acting as a backing material, CDX plywood can add rigidity and structural support to the siding system. This helps prevent warping, buckling, or other forms of distortion that might occur if the siding were directly attached to the wall framing.
Temporary Structures:
CDX plywood is sometimes used in temporary structures, such as construction site fencing, hoarding, or barricades.
Its durability and weather resistance make it suitable for these short-term applications.
If you desire to install a temporary boundary for instance, CDX plywood is perfect. You can also use it for structures like hoarding or screens that can shield construction activity from the public.
Concrete Formwork:
CDX plywood can be used to create formwork for casting concrete structures, such as foundations, columns, and beams. It provides a smooth and even surface for the concrete to set against and helps shape the final structure.
Outdoor Furniture and Playsets:
Due to its weather resistance, CDX plywood can be used to build outdoor furniture, playsets, and other outdoor structures that need to withstand exposure to the elements.
Packaging and Crating:
CDX plywood is sometimes used in packaging and crating applications where a sturdy and reliable material is needed to protect and transport goods.
Workbenches and Workshop Surfaces:
In woodworking shops and garages, CDX plywood can be used to build workbenches, shelving, and other functional surfaces.
Temporary Repairs:
CDX plywood can be used for temporary repairs or patches on exterior surfaces, such as covering holes or damaged areas in a pinch.
CDX Plywood size and thickness
CDX plywood is available in a range of sizes and thicknesses to accommodate different project requirements.
The standard sizes and thicknesses of CDX plywood are as follows:
Standard Sizes:
- 4 feet by 8 feet: This is the most common size for CDX plywood sheets, making it easy to handle, transport, and install.
- It’s suitable for a wide range of construction projects and can be cut down to smaller sizes if needed.
Thicknesses:
- 3/8 inch (9.525 mm): CDX plywood at this thickness is often used for wall and roof sheathing, as well as for subflooring in areas where floor height is a concern.
- 1/2 inch (12.7 mm): This thickness is commonly used for roof decking, wall sheathing, and subflooring. It provides a good balance between strength and weight.
- CDX Plywood 5/8 inch (15.875 mm): CDX plywood of this thickness is suitable for heavy-duty flooring, including in areas with high foot traffic or heavy loads.
- CDX Plywood 3/4 inch (19.05 mm): The thickest CDX plywood option, this is used for heavy-duty applications such as flooring, support beams, and other structural elements.
variations may exist based on manufacturer and region.
When selecting CDX plywood for your project, consider the specific load-bearing requirements, intended use, and environmental conditions to ensure you choose the appropriate size and thickness.
CDX Plywood prices
The price of CDX plywood can vary widely based on factors such as location, supplier, current market conditions, and specific brand. Additionally, the size and thickness of the CDX plywood sheets will also influence the cost.
As you will note in the table below, prices for CDX plywood also depends on the amount of sheets or square meters that you are buying. The higher the number of sheets, the lower the pricing.
After contacting 15 of the top flooring wholesalers in the USA, these were the average prices for the CDX plywood:
| Thickness | 1-200 Sheets | 21-40 Sheets | 41+ Sheets | Wood Type |
| 12mm | $ 17.85 | $16.63 | $16.00 | FIR |
| 18mm | $25.48 | $ 23.72 | $22.84 | FIR |
| 24mm | $5.32 | $ 53.37 | $51.39 | FIR/PINE |
In the event that you may want to bulk import from online wholesalers like Alibaba or Express, these are the prices you will be paying;
| Thickness | 1-200 Sheets | 21-40 Sheets | 41+ Sheets | Wood Type |
| 12mm | $ 11.49 | $9.25 | $6.03 | Fir |
| 18mm | $15.48 | $ 13.72 | $9.84 | Pine |
| 24mm | $22.32 | $ 18.37 | $14.39 | Pine |
What is CDX Treated plywood?
CDX treated plywood refers to plywood that has been treated with chemical preservatives to enhance its resistance against decay, rot, and insect damage. This treatment process helps extend the lifespan of the plywood when used in outdoor or high-moisture environments.
CDX treated plywood maintains the basic construction and grading characteristics of traditional CDX plywood, making it suitable for applications such as exterior sheathing, subflooring, and other outdoor projects where durability and weather resistance are important.
Is CDX Plywood waterproof?
CDX plywood is not inherently waterproof and thus not suitable for wet areas. While it does have some level of water resistance due to the adhesives and natural properties of wood, it is not designed to be completely waterproof. CDX plywood is often used in exterior and structural applications where it might be exposed to moisture, but it should not be relied upon as a primary waterproofing barrier.
To enhance its moisture resistance, CDX plywood can be further treated with water-repellent coatings or sealants. However, for applications that require a high degree of waterproofing, such as in areas prone to heavy rain or continuous water exposure, other types of plywood specifically designed for marine or outdoor use, such as marine-grade plywood or pressure-treated plywood, may be more suitable.
Ultimately, if waterproofing is a critical factor for your project, it’s important to carefully consider the specific plywood grade and treatment options available to meet your needs and to consult with professionals or experts in the field.
How long can CDX Plywood be exposed?
CDX plywood can withstand exposure to the elements for a limited period, but its durability will depend on several factors, including the quality of the plywood, the specific environmental conditions it’s exposed to, and whether any protective measures have been taken.
Here are some general considerations:
Quality of Plywood:
CDX plywood is commonly used for exterior applications, but its longevity can vary based on the quality of the plywood itself.
Higher-grade plywood with better adhesives and more durable veneers may last longer when exposed to the elements.
Moisture Exposure:
CDX plywood is relatively resistant to moisture, but prolonged exposure to high levels of moisture, such as continuous rain or submersion, can lead to swelling, warping, and deterioration over time.
Sunlight and UV Exposure:
Sunlight and ultraviolet (UV) rays can degrade the wood fibers and adhesives in CDX plywood over time. Proper finishing or coating can help protect against UV damage.
Maintenance and Coatings:
Applying water-resistant sealants, paints, or other protective coatings can significantly extend the lifespan of CDX plywood when exposed to the outdoors. Regular maintenance, such as resealing or repainting, may be necessary to prolong its usable life.
Location and Climate:
The climate in your area plays a significant role. CDX plywood exposed to milder, temperate climates may last longer than in harsher environments with extreme temperature variations and severe weather.
In general, CDX plywood is often used for temporary outdoor structures, construction site uses, or short-term applications.
For longer-lasting exterior projects or structures requiring extended exposure, considering marine-grade plywood or pressure-treated plywood might be a better option, as these types of plywood are specifically designed to withstand moisture and environmental stresses over a longer period.
If you’re unsure about the appropriate choice for your project, it’s recommended to consult with professionals or experts in construction and woodworking.
