Many ask about using Waterlox® products on decks or porches in direct sunlight. Usually, they have used our interior products and loved the results, so they wonder if we have anything for exterior flooring. Or they may have used our Find Your Finishing System Form and discovered our MARINE Product line, only to find this disclaimer: “Our MARINE finishing system is not recommended for use on exterior horizontal walking surfaces, such as decks or any pre-treated lumber.” So does Waterlox® offer a solution for decks? The Waterlox® 100% PURE Tung Oil and Waterlox® MARINE Formula can both be used on decks, but it’s important to know all of the details first.
Key Factors to Consider
When working with an exterior wood surface, there are a few key factors that coatings need to address. These are, in order of importance:
- Water exposure
- Sun exposure
- Humidity
- Wear and tear
The biggest challenge with exterior clear coatings is that they need to be regularly reapplied to maintain protection, thereby having a trade-off between lifespan of the coating and difficulty of the maintenance.
Using Waterlox® 100% PURE Tung Oil
Tung oil has been used as a wood coating for centuries and is described as first being used to protect Chinese sailing vessels. So, it will work well on most exterior projects, including decks.
Waterlox® 100% PURE Tung Oil will soak into and saturate the wood to repel water and keep the wood oiled. It will also maintain the warm rich color. Using Pure Tung Oil on any surface will yield an unfinished look — it will not build up to a glossy film coating. Tung oil will naturally resist mold and mildew. However, it does not contain any additional biocides, so they are not 100% eliminated. There is more information in the mold and mildew guide. There are no additional UV absorbers added to the Pure Tung Oil, but if the wood remains saturated it will help to prevent fading or graying. Tung oil will slowly wear away over time with use and exposure. The signal for reoiling will be discoloration and/or when water no longer beads up on the surface.
For detailed instructions see our Pure Tung Oil on Decks guide.
Using Waterlox® MARINE Products
There are three things to keep in mind when using the MARINE finishes on decks:
- Lifespan
- Maintenance
- Hardness
Waterlox® MARINE finishes are designed to be film-forming coatings that can withstand regular UV exposure. When MARINE finishes are first applied, they provide excellent protection. However, regular maintenance is required. The lifespan of the finish is dependent on the amount and intensity of sun exposure. Coatings on well shaded decks may last for many years before recoating becomes necessary, but a fully-exposed wood decks may require recoating as often as every 6 months. Our MARINE finishes tend to dull as they reach the end of their lifespan, so they will not completely fail if maintained in time. It is a simple, clean and re-coat process when the film has faded.
However, if left unattended, the film can eventually flake, chip or peel as the UV further degrades and shrinks the film past its recoat cycle time. This leads to a larger maintenance project. The surface needs to be clean and the environment and weather need to be right to minimize dust, airborne debris and rain. Sanding or multiple applications may be needed.
In terms of hardness, the flexibility of the finish reduces its scratch resistance. The level of durability of the MARINE system is not at the same level as your typical floor finish.
In summary: The MARINE finishes are not designed for heavy use and may scratch easier than desired. Recoating can be frequent, so large projects in full sun are not ideal. Recoating requires some prep work and may require spot touch ups and a full reapplication.
