How Do You Waterproof a Plastic Storage Box?

Plastic storage boxes are a practical solution for organizing and storing various items, from seasonal clothing and holiday decorations to important documents and tools. While these boxes are generally sturdy and resistant to many elements, they are not always entirely waterproof. To protect your stored items from moisture, rain, or even potential flooding, it’s crucial to waterproof your plastic storage box effectively. Here’s how you can do it.

Understanding the Need for Waterproofing

Even though plastic is inherently water-resistant, the design of many storage boxes may include seams, gaps around lids, or small openings that allow water or moisture to seep in. This is especially true for boxes stored in basements, garages, or outdoor sheds where they may be exposed to damp conditions, rain, or leaks. Waterproofing a plastic storage box not only prevents water damage but also protects against mold, mildew, and the potential degradation of the stored contents.

Steps to Waterproof a Plastic Storage Box

Waterproofing a plastic storage box involves both sealing any potential entry points for water and enhancing the box’s overall resistance to moisture. Here’s a step-by-step guide on how to achieve this:

1. Select a High-Quality Box

The first step in waterproofing is to start with a high-quality plastic storage box. Look for boxes that have a tight-fitting lid with a gasket or rubber seal, which can provide a basic level of water resistance. Boxes made from thicker, more durable plastic are also preferable, as they are less likely to crack or warp over time, which could compromise their waterproofing.

2. Seal the Lid and Seams

If your plastic storage box doesn’t already have a rubber gasket around the lid, you can create a similar effect using weather stripping or silicone sealant. Apply a thin strip of adhesive weather stripping around the edge of the lid where it meets the box. This will create a tight seal when the lid is closed, preventing water from entering through the gaps.

Alternatively, a silicone sealant can be applied along the seams and edges of the box, especially if there are any visible gaps or imperfections. Make sure to use a waterproof, flexible silicone that can withstand temperature fluctuations without cracking. Allow the sealant to cure fully before using the box.

3. Use Waterproofing Sprays

Waterproofing sprays designed for plastic can provide an additional layer of protection. These sprays create a hydrophobic barrier on the surface of the plastic, repelling water and preventing it from sticking to the surface. To apply, clean the surface of the box thoroughly and allow it to dry. Then, evenly spray the waterproofing agent over the entire exterior, paying special attention to the seams and edges. Let the spray dry according to the manufacturer’s instructions before using the box.

4. Line the Inside of the Box

For added protection, consider lining the inside of the box with a waterproof material such as a plastic sheet or tarp. This is particularly useful if you’re storing items that are highly sensitive to moisture. The liner acts as a secondary barrier in case any water does manage to seep through the box. Secure the liner to the sides of the box using waterproof tape, making sure it covers the entire interior.

5. Elevate the Box

If your plastic storage box will be stored in a location prone to water exposure, such as a basement or garage floor, elevating the box can help keep it dry. Place the box on a pallet, bricks, or another type of platform to keep it off the ground. This prevents direct contact with any water that might accumulate on the floor during heavy rains or flooding.

6. Check Regularly

Even after waterproofing, it’s important to regularly check your plastic storage boxes for signs of wear, damage, or leaks. Over time, seals can deteriorate, and boxes can develop cracks. Inspect the box and reapply sealant or waterproofing spray as needed. This routine maintenance will help ensure that your storage box remains waterproof and that your items stay protected.