What Kind of Coating Do I Put on My Wood to Keep It Sealed?

Wood Sealant

• Wood sealant is a chemical produced by various manufacturers that can be directly applied to either treated or untreated wood. Sealant is composed of several materials such as vinyl, epoxy and polyurethane. It works by filling in pores within the wood and smoothing out sharp wood grains, thus helping prevent liquid absorbency.

Sealant Application

• Wood sealant can be applied directly to bare wood after it has been sanded. Sand down the wood with 100-grit sandpaper to smooth it out and remove any wood splinters. Sealant may then be applied in thin coats with a paintbrush or as a spray. Enough should be used so that it penetrates the wood, but not so much that it saturates or oversoftens it.

Varnishes

• Varnishes are chemicals that coat wooden surfaces and provide a clear, thin protective barrier. Many varnishes will work to keep out liquid while allowing the natural look of the wood to shine through. Varnishes are composed of different materials that are better for protecting wood from certain environments. Phenolic and alkyd-based varnishes are ideal for exterior use, for example, while polyurethane varnishes are better for indoor usage, as they may crack or yellow with exposure to the intense UV light of the sun. Varnishes are applied after wood sealants and are typically coated using a brush.

Water Repellents

• Water repellents should be the final coat over wood to help seal out water. These repellents act as a clear coating over the varnish layer and often contain a mildewicide to kill any mildew that may attempt to build up over time. Water repellents are often applied with brushes and should be reapplied every few months to maintain their effectiveness.