Cork is not waterproof, but it is water-resistant to some extent. When exposed to prolonged or repeated exposure to moisture, it will start absorbing the moisture.
In other words, cork can resist the penetration of moisture and water to some degree but not entirely.
The higher the water pressure, the faster it will seep through the cork.
What makes cork water resistant?
Cork has a hexagonal-like cellular structure composed of air-filled pockets that make it water-resistant. These pockets also make cork compressible, elastic, and lightweight.
Cork is around 15 percent solid and 85 percent air.
Its water resistance properties vary depending on several factors, such as the thickness and density of the cork layer, the duration of exposure to water, and environmental conditions.
Can you make cork waterproof?
You can seal cork products with a coating of polyurethane acrylate or silicone. This will prevent moisture and water from passing through the cork.
To get the job done, you’ll need sandpaper, a paintbrush, and a waterproof sealant of your choice.
Steps to make cork waterproof
1. Clean the cork surface
You can use a soft brush or sponge to remove any dirt or debris. If you’re having trouble removing dirt, you can use a damp cloth.
Just make sure to let your cork product dry completely before applying the waterproof sealant.
2. Sand the cork surface
This step is optional. Use fine-grit sandpaper to even out the cork surface and allow the sealant to adhere better.
If there are no bumps or other issues on the cork surface, jump to the next step.
3. Apply the waterproof sealant
Use a soft paintbrush and apply a thick, even coat of waterproof sealant. Make sure to cover the entire surface.
Let the sealant dry overnight in a well-ventilated area.
If this is an outdoor cork product, apply an additional coat of sealant and let it dry.
Your cork product should now be fully waterproof. Water will bead up when it comes into direct contact with your cork product.
⇒ Important note:
- Don’t use waterproof sealant in an enclosed space. This can be potentially harmful due to the release of volatile compounds present in the sealant.
What happens when cork gets wet?
When cork is exposed to moisture or water and gets wet, it will expand and lose its shape. If it remains wet for an extended period, it can become saturated, deteriorate, and warp.
Take care of your cork products, keep them dry, and avoid water exposure to prolong their lifespan.
Don’t forget to apply a coating of waterproof sealant if needed.
Will water evaporate through cork?
Water can evaporate through cork over time, especially if the surface is exposed to warm, dry air.
The rate of evaporation is very slow and varies depending on the thickness and density of the cork, the amount of water present, the temperature, and the level of air circulation.
Can cork withstand rain?
Cork can withstand rain to some extent. Exposure to heavy rain can cause cork to absorb water, expand, warp, and deteriorate. To prevent that from happening, make sure your outdoor cork products are sealed and protected.
Apply a waterproof coating to prevent water from penetrating the cork.
If you want your cork products to last longer, keep them out of direct rain whenever possible.
How long does cork last?
The lifespan of cork varies depending on its quality, exposure to the elements, and level of wear and tear.
High-quality cork products can last for decades with proper care and maintenance.
Of course, lower-quality cork products will have a shorter lifespan.
To extend the lifespan of your cork products, follow the manufacturer’s instructions for care and maintenance.
Equally important, avoid exposing cork to harsh chemicals, prolonged exposure to moisture, and environmental factors such as direct sunlight and rain.
Applying a protective sealant will prolong the lifespan of your cork products.
If you’re using cork products in your bathroom or kitchen, seal them to prevent moisture from seeping in and causing damage over time.
Read the manufacturer’s instructions carefully to learn how to properly take care of your cork products and avoid damaging them.
How long does it take for cork to decompose in water?
The rate at which cork decomposes in water varies depending on several factors, such as the thickness and quality of the cork, the temperature of the water, and whether it has been treated with a protective sealant or not.
It will typically take untreated cork between 3 to 5 years to fully decompose in water. Cork products treated with a protective sealant will take longer to decompose.
As you can see, cork will not decompose rapidly in water.
- Cork: Structure, Properties, Applications @ Harvard Arboretum.