Waterproof Plywood: Myths vs. Facts

Waterproof Plywood: Myths vs. Facts

When it comes to construction and woodworking, plywood is a versatile and widely used material. Its durability and affordability make it a top choice for various applications, from building furniture to constructing houses. 

However, there’s a common misconception about plywood that needs to be clarified: the idea that all plywood is waterproof. 

In this blog post, we’ll delve into the myths and facts surrounding waterproof plywood to help you make informed decisions for your projects.

Myth 1: All Plywood Is Waterproof

One of the most prevalent myths is the belief that all plywood is inherently waterproof. This misunderstanding may lead to costly mistakes, especially in projects where moisture resistance is crucial. 

In reality, plywood comes in various types, and its water resistance depends on the specific type and manufacturing process.

Fact: Plywood is typically categorized into two main types based on its water resistance—interior and exterior. Interior plywood is not designed to withstand exposure to moisture and should only be used in dry, controlled environments such as indoors. 

Exterior plywood, on the other hand, is manufactured with special glues and treatments to make it resistant to moisture and suitable for outdoor use. 

Even within these categories, there are further distinctions in terms of water resistance, so it’s essential to choose the right type of plywood for your specific project.

Understanding the differences between interior and exterior plywood is crucial for preventing structural damage and ensuring the longevity of your projects. When selecting plywood, always check the product specifications and choose the type that matches your project’s environmental conditions.

Myth 2: Waterproof Plywood Can Be Exposed to Water Indefinitely

Another misconception is that waterproof plywood can be submerged or exposed to water indefinitely without any damage. 

While waterproof plywood is designed to resist moisture better than its interior counterpart, it is not entirely impervious to water.

Fact: Waterproof plywood can withstand exposure to moisture, but it is not designed for long-term immersion in water. Prolonged exposure can lead to swelling, warping, and delamination of the layers. 

To ensure its longevity, it’s crucial to protect waterproof plywood from excessive moisture and take preventive measures, such as applying a waterproofing sealant, to enhance its resistance. 

Even in outdoor applications, where waterproof plywood is commonly used, it should be adequately protected from direct contact with water.

Myth 3: All Waterproof Plywood is the Same

Some people assume that all waterproof plywood is identical in terms of quality and performance. This misconception can lead to disappointing results and project failures if subpar materials are used.

Fact: Not all waterproof plywood is created equal. There are significant differences in quality and performance between various brands and grades of waterproof plywood. To ensure the best results for your project, it’s essential to do your research and select a reputable supplier known for providing high-quality waterproof plywood. 

Consider factors such as the plywood’s source material, manufacturing process, and certifications for water resistance. Investing in a superior product may cost a bit more upfront but can save you time and money in the long run by preventing premature deterioration and costly replacements.

Myth 4: Waterproof Plywood Is Maintenance-Free

Another myth is that once you’ve used waterproof plywood, you can forget about maintenance entirely. This belief can lead to long-term problems, especially in outdoor applications.

Fact: While waterproof plywood is more resistant to moisture than interior plywood, it still requires proper maintenance to ensure its durability. Regular inspections and preventive measures are essential, especially for outdoor installations. 

Apply a waterproof sealant or paint to protect the surface from moisture and UV rays, which can cause damage over time. Additionally, ensure that the plywood is adequately ventilated to prevent the buildup of moisture that can lead to mold and rot. 

By taking these maintenance steps, you can extend the lifespan of your waterproof plywood and maintain its structural integrity.

Myth 5: Waterproof Plywood Is Fireproof

Some people mistakenly believe that waterproof plywood is also fireproof. This misconception can have serious safety implications, particularly in construction projects where fire resistance is critical.

Fact: Waterproof plywood is not fireproof. It may have some fire-resistant properties, depending on the specific type and treatment, but it is not a substitute for proper fire-rated materials. 

When fire resistance is a requirement, it’s essential to use materials explicitly designed and tested for that purpose, such as fire-rated drywall or sheathing. Relying on waterproof plywood for fire resistance can put lives and property at risk.

Myth 6: Waterproof Plywood Is Cost-Prohibitive

Another common myth is that waterproof plywood is prohibitively expensive, leading some to opt for cheaper alternatives, even when water resistance is essential.

Fact: While waterproof plywood can be more expensive than interior plywood, it’s essential to consider the long-term costs and benefits. 

Investing in high-quality waterproof plywood can save you money in the long run by preventing the need for costly repairs or replacements due to moisture-related damage. 

Moreover, the added durability and resistance to decay can extend the lifespan of your project, making it a worthwhile investment.

Myth 7: Any Waterproofing Sealant Will Do

Some believe that any waterproofing sealant can be applied to waterproof plywood, assuming they all provide the same level of protection.

Fact: Not all waterproofing sealants are suitable for plywood, and their effectiveness can vary significantly. The choice of sealant should align with the type of plywood you’re using and the intended application. 

Some sealants are specifically designed for exterior plywood, while others are better suited for interior use. Be sure to read the manufacturer’s recommendations and choose a sealant that matches your project’s requirements.

Myth 8: Plywood Edges Don’t Require Sealing

Many people overlook the importance of sealing the edges of plywood when waterproofing it, assuming that treating the surface alone is sufficient.

Fact: Sealing the edges of plywood is just as crucial as treating the surface. Plywood edges are particularly vulnerable to moisture infiltration and can lead to delamination if left unprotected. 

To ensure comprehensive water resistance, apply a sealant to all exposed edges of the plywood, including any cut edges. This extra step can significantly enhance the plywood’s longevity and performance.

Myth 9: All Waterproof Plywood Is Environmentally Unfriendly

Some individuals mistakenly believe that all waterproof plywood is harmful to the environment due to the chemicals and treatments used to enhance its moisture resistance.

Fact: While it’s true that some types of waterproof plywood may involve the use of certain chemicals and treatments, not all are environmentally unfriendly. Many manufacturers are increasingly adopting eco-friendly practices, using sustainably sourced materials, and opting for low-VOC (volatile organic compound) adhesives and treatments. 

When environmental concerns are a priority, you can find waterproof plywood options that align with your sustainability goals. Always check for certifications and inquire about the manufacturing process to ensure you’re making an environmentally responsible choice.

Myth 10: Waterproof Plywood Is Only Suitable for Outdoor Projects

A prevalent misconception is that waterproof plywood should only be used for outdoor applications, leading some to overlook its advantages for indoor projects.

Fact: Waterproof plywood’s resistance to moisture can benefit indoor projects as well. In areas prone to high humidity, such as bathrooms and kitchens, or in places where occasional water exposure is possible, like laundry rooms, using waterproof plywood can help prevent damage and maintain structural integrity. 

It’s a versatile material suitable for both indoor and outdoor projects, depending on the specific type and grade chosen.


In conclusion, understanding the myths and facts surrounding waterproof plywood is essential for anyone working with this versatile building material. By dispelling common misconceptions and adhering to best practices, you can make informed decisions and ensure the success and durability of your projects. 

Remember that not all plywood is created equal, and choosing the right type, quality, and maintenance procedures are key to harnessing the full potential of waterproof plywood in your construction and woodworking endeavors.

If you require different types of plywood, you can explore the market to discover a diverse range of choices. These options encompass fire retardant plywood, zero-emission plywood, marine plywood, calibrated plywood, and more. It’s important to select the most suitable option based on your specific needs and preferences.

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