One of the reasons waxed cotton or canvas is so popular is its water-repelling abilities. On its own, cotton readily absorbs water. This is because the cotton fibers have a lot of space between them, so water moves to fill out these spaces. However, when the cotton is treated with wax such as paraffin-based wax or beeswax, it develops a waterproof nature. It is also weatherproof, meaning the wind won't be able to penetrate either.