Plywood is a versatile material that can be used for a variety of projects, ranging from construction to home improvement to making woodworking jigs. It is strong, durable, and easy to use making it one of the popular choices for both DIYers and professionals. Unfortunately, plywood is not waterproof, and when it comes into contact with moisture, it can quickly deteriorate and even become unusable. This is why it is crucial to take the time to properly waterproof plywood, especially if used outdoors.
Waterproofing plywood offers numerous benefits, including extending its lifespan, preventing warping, and rotting, and protecting against mold and mildew growth.
There are several methods for waterproofing plywood, including varnish, epoxy, waterproof paint, and PVA glue each with its own advantages and disadvantages. By understanding the various options available and choosing the best method for your specific project, you can ensure that your plywood remains protected and in top condition for years to come.
Throughout this article, I will cover each method in detail, outlining the pros and cons and providing step-by-step instructions on how to waterproof plywood. Plus, I will share some useful tips to ensure your project is a success.
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Table of Contents
- General Questions
- Is plywood waterproof?
- What are the benefits of waterproofing plywood?
- How long does waterproofed plywood last?
- Waterproofing plywood edges?
- Types of waterproof plywood
- How to Waterproof Plywood (Different Methods)
- Conclusion
Is plywood waterproof?
Although plywood is a versatile material for a wide range of projects, it is essential to know that it is not fully waterproof. Plywood is susceptible to water damage when it is exposed to moisture.
To understand why plywood is not waterproof, it’s essential to know what it’s made of and how it’s constructed. Plywood is made from layers of wood veneers that are glued together in a cross-grain pattern, which adds to its strength and stability. However, this construction also means that the wood is susceptible to water damage because the glue used in its construction can break down over time.
Compared to solid wood, plywood is partially water-resistant, but it’s not entirely immune to water. When exposed to moisture, plywood can swell, warp, or delaminate, which can compromise its structural integrity.
However, there are some types of plywood that are specially designed to be more water-resistant, such as CDX plywood and ABX plywood. These types of plywood are excellent choices for outdoor use or any application where water resistance is necessary.
What are the benefits of waterproofing plywood?
When it comes to plywood, there’s no denying its versatility and strength. However, without proper protection, it can quickly succumb to the damaging effects of moisture. That’s where waterproofing comes in, offering a range of benefits that can help you get the most out of your plywood. Here are a few ways in which waterproofing can make a real difference:
- Keep Rot at Bay: Nobody wants to see their plywood succumb to rot and decay. By waterproofing your plywood, you can create a barrier that keeps moisture out and preserves the wood for years to come.
- Combat Warping: When wood gets wet, it can expand and contract, leading to unsightly warping and distortion. With waterproofing, you can keep your plywood flat and stable, even in the face of moisture.
- Prevent Splitting: Nothing ruins a project faster than a split piece of plywood. Fortunately, waterproofing can help reduce the risk of splitting and cracking, ensuring that your DIY creations stay intact.
- Extend Your Investment: By waterproofing your plywood, you’re making an investment in its future. With proper maintenance, waterproofed plywood can last far longer than untreated wood, saving you time and money in the long run.
How long does waterproofed plywood last?
When it comes to waterproofing plywood, many people wonder how long their efforts will last. The answer, unfortunately, is that it depends on the method you use.
Below, you will find a table that outlines various methods of waterproofing plywood, along with their expected lifespan in terms of protecting against moisture damage.
Waterproofing Method | Estimated Lifespan |
Plastic Sheeting | 1-2 years |
Waterproof Paint | 2-5 years |
Liquid Latex | 5-10 years |
PVA Glue | 5-10 years |
Varnish (Polyurethane) | 10-15 years |
Epoxy Sealant | 15-20 years (or more) |
NOTE: The estimated lifespans are based on average use and conditions and can vary depending on factors such as climate and exposure to water.
Waterproofing plywood edges?
If you are working with plywood, you may be wondering if it’s necessary to waterproof the edges. The answer is yes – the edges are often the most vulnerable part of the plywood when it comes to water damage. Sealing the edges can help to prevent moisture from penetrating the plywood and causing it to warp or rot.
Types of waterproof plywood
The market offers a diverse range of plywood types, each with specific qualities and applications. When it comes to waterproof plywood, certain types stand out for their superior performance in outdoor settings. To help you choose the best one for your project, check out the table below, which classifies some of the most common types of plywood based on their quality and ideal usage.
| Type of Plywood | Abbreviation | Quality | Usage | Price Range |
| AAX Plywood | AAX | High | Outdoor | High |
| ABX Plywood | ABX | High | Outdoor | High |
| ACX Plywood | ACX | Medium | Outdoor/Indoor | Medium |
| ADX Plywood | ADX | Medium | Outdoor/Indoor | Medium |
| BWP Plywood | BWP | High | Outdoor/Indoor | High |
| MR Grade Plywood | MR | Medium | Indoor | Low |
| BWR Plywood | BWR | Medium | Indoor | Low |
| CDX Plywood | CDX | Low | Indoor | Low |
Plywood types:
- AAX and ABX plywood are high-quality plywood with superior waterproofing properties, making them perfect for outdoor use.
- ACX and ADX plywood is medium-quality plywood suitable for indoor and outdoor use, depending on the project’s requirements.
- BWP plywood is high-quality waterproof plywood specially designed for use in humid and damp environments, such as bathrooms and kitchens.
- MR Grade and BWR plywood are medium-quality plywood that is primarily used for indoor applications, such as furniture making and paneling.
- CDX plywood is low-quality plywood commonly used for interior construction and other non-decorative purposes. It is not recommended for outdoor use or in wet areas.
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How to Waterproof Plywood (Different Methods)
Waterproofing plywood can help prevent damage from moisture, extending its lifespan and preserving its integrity. There are several techniques to choose from, including plastic sheeting, waterproof paint, liquid latex, PVA glue, varnish, and epoxy sealant. Let’s take a closer look at each of these methods.
Method | Quality and Durability | Indoor/Outdoor Use | Price |
Plastic sheeting | Moderate | Outdoor | Low |
Waterproof paint | Moderate to High | Indoor/Outdoor | Moderate to High |
Liquid latex | Moderate | Indoor | Moderate |
PVA Glue | Moderate | Indoor | Low |
Varnish (Polyurethane) | High | Indoor/Outdoor | High |
Epoxy Sealant | High | Indoor/Outdoor | High |
NOTE: the quality and durability, as well as indoor/outdoor use, may vary depending on the specific brand and application method used
Method 1: Plastic Sheeting
Plastic sheeting is a common and affordable method for waterproofing plywood. It involves applying a plastic sheet or film onto the surface of the plywood and sealing it in place. This creates a barrier that prevents moisture from penetrating the surface and reaching the plywood.
PROS:
- Affordable: Plastic sheeting is a cheap and readily available option for waterproofing plywood.
- Easy to apply: It is a simple process that requires minimal equipment and can be done quickly.
- Versatile: The plastic sheeting can be cut to fit any size of plywood, making it a flexible option for different projects.
CONS:
- Limited lifespan: The plastic sheeting can break down over time, especially when exposed to UV rays, causing it to lose its effectiveness.
- Not very durable: It can be easily punctured or torn, which can lead to moisture getting through.
- Aesthetics: Plastic sheeting is not the most visually appealing option, and can be difficult to paint or decorate.
Summary:
Plastic sheeting is an affordable and easy way to waterproof plywood. It provides a strong and durable protective layer that can effectively prevent moisture from penetrating the wood. However, it may not be the most visually appealing option and may not offer the same quality and longevity as other methods
Method 2: Waterproof Paint
Waterproof paint is a coating that can be applied to plywood to prevent water penetration. It works by creating a barrier that repels water and prevents it from seeping into the wood.
PROS:
- Easy to apply: Waterproof paint can be applied with a brush or roller, making it a simple process.
- Durable: Once applied, waterproof paint can provide long-lasting protection against water damage.
- Aesthetically pleasing: Waterproof paint is available in a variety of colors, allowing for customization and an attractive finish.
CONS:
- Limited protection: Waterproof paint is not as effective as other methods in preventing water damage.
- May require multiple coats: Depending on the quality of the paint, multiple coats may be necessary to achieve adequate protection.
- Not suitable for high-traffic areas: Waterproof paint may peel or wear off in areas with high foot traffic or frequent use.
Summary:
Waterproof paint is a relatively inexpensive option for waterproofing plywood, but may not provide the same level of protection as other methods. While it is durable and aesthetically pleasing, it may require multiple coats and is not suitable for high-traffic areas.
Method 3: Liquid Latex
Liquid latex is a water-based coating that creates a protective barrier on the surface of plywood, preventing water from penetrating the material. It works by forming a flexible and elastic film that can withstand expansion and contraction of the plywood due to changes in temperature and humidity.
PROS:
- Easy to apply: Liquid latex can be easily applied with a brush or roller, and it dries quickly.
- Durable: It provides long-lasting protection against water damage and decay.
- Flexible: The coating can stretch and move with the plywood without cracking or peeling.
CONS:
- Limited color options: Liquid latex is typically only available in white or clear, limiting its use for decorative projects.
- Difficult to remove: Once applied, it can be challenging to remove the coating if needed.
- Not ideal for heavy use: Liquid latex is not recommended for surfaces that will experience heavy wear and tear.
Summary:
Liquid latex is a mid-range option in terms of price, but it provides a good balance of durability and flexibility. It may be more expensive than plastic sheeting and PVA glue, but it is typically less expensive than varnish and epoxy sealant.
Method 4: Varnish
Varnish is a popular method for waterproofing plywood that involves applying a protective layer of resin to the surface of the wood. This coating provides a durable barrier against moisture, making it an ideal solution for both indoor and outdoor applications.
PROS:
- Durability: Varnish creates a hard and durable surface that can withstand wear and tear, making it a great option for high-traffic areas.
- Aesthetics: Varnish can enhance the natural beauty of the wood by adding a glossy finish that highlights the wood grain.
- UV Protection: Some types of varnish contain UV-resistant additives that protect the wood from sun damage.
CONS:
- Labor-Intensive: Applying varnish can be time-consuming and requires several coats to achieve optimal waterproofing.
- Hazardous Chemicals: Varnish contains chemicals that can be hazardous to work with, so proper safety precautions must be taken.
- Cost: Varnish can be more expensive than other waterproofing methods, especially if high-quality varnish is used.
Summary:
In terms of price, varnish is generally more expensive than plastic sheeting or PVA glue but may be less expensive than epoxy sealant. However, the durability and aesthetics of varnish may make it a worthwhile investment in certain projects.
Method 5: Epoxy Sealant
Epoxy sealant is a two-part adhesive that creates a strong and durable waterproof seal. It is commonly used to waterproof plywood by coating it with a sealant mixture.
PROS:
- Durable: Epoxy sealant creates a long-lasting waterproof seal that can withstand extreme weather conditions
- Versatile: It can be used on a variety of surfaces, including plywood, metal, and concrete.
- Easy to apply: Epoxy sealant can be applied using a spray or paint form, making it easy to use for both small and large projects.
CONS:
- Costly: Epoxy sealant can be more expensive than other waterproofing methods, especially for large projects.
- Time-consuming: The application process can be time consuming, requiring multiple coats and adequate drying time.
- Toxic fumes: The fumes from the epoxy sealant can be harmful if inhaled, so proper ventilation and protective gear should be used during application.
Summary:
In summary, the strength of epoxy sealant lies in its durability and versatility. However, its high cost and time-consuming application process may not be feasible for some projects. It is important to consider the project’s size and budget when choosing the appropriate waterproofing method.
Method 6: PVA Glue
PVA glue is a water-based adhesive that is often used to waterproof plywood. It penetrates the wood fibers and creates a barrier against moisture. It has several benefits, such as ease of application, transparent drying, and affordability.
PROS:
- Easy Application: PVA glue is simple to apply and can be easily found at hardware or craft stores.
- Transparent Drying: PVA glue dries clear, allowing the natural wood grain to show through.
- Affordable: Compared to other waterproofing methods, PVA glue is an inexpensive option for waterproofing plywood.
CONS:
- Limited durability: PVA glue is not as durable as other waterproofing methods and may need to be reapplied more frequently.
- Not suitable for constant water exposure: While PVA glue can withstand some water exposure, it is not recommended for constant water exposure.
- Not suitable for outdoor use: PVA glue is not the best option for outdoor use as it can break down in harsh weather conditions.
Summary:
PVA glue is an affordable and easy-to-apply option for waterproofing plywood. However, it may not be as durable as other methods and is not recommended for constant water exposure or outdoor use. Compared to other methods, PVA glue is generally less expensive but may need to be reapplied more frequently.
Conclusion
If you’re looking to waterproof plywood, there are several methods available to choose from. You can use plastic sheeting, waterproof paint, liquid latex, varnish, epoxy sealant, or PVA glue.
Each of these methods has its own set of pros and cons, which you will need to weigh up based on your budget and the specific needs of your project.
Keep in mind that some of these methods are better suited for indoor use while others are better suited for outdoor use, so it is important to consider your end goal when choosing a waterproofing method.
