Best Outdoor Wood Finishes Reviewed

Outdoor Wood Finishes: Everything I Learned the Hard Way

Outdoor wood is a whole different beast. I made the mistake early on of treating my first outdoor bench like indoor furniture. Used the same finish I would use on a coffee table. By the following spring, it looked like it had been abandoned for a decade.

Rain, sun, temperature swings, bugs, mold – outdoor wood faces challenges that indoor pieces never see. The finish has to fight all of that, not just protect against the occasional water ring.

The Main Options

Oil-Based Finishes

Penetrating oils like tung and linseed can work outdoors, but they need frequent reapplication. I am talking every few months in harsh climates. They soak in deep which is good, but they do not create a surface barrier against water.

Some outdoor oils have UV blockers added. That helps with sun damage, which is actually a bigger problem than most people realize. UV breaks down lignin in wood, causing that gray weathered look.

I use oil-based products on outdoor furniture that I can easily maintain – Adirondack chairs, small tables, stuff I can refinish in an afternoon. For larger projects, the maintenance burden gets old fast.

Spar Varnish

This is the gold standard for outdoor wood in my opinion. Originally designed for boat masts (the spars), it stays flexible even as wood expands and contracts with humidity changes. Most other finishes crack because they are too rigid.

Multiple coats build up a serious protective layer. It looks great – nice warm amber color and a glossy or satin sheen depending on what you buy. And it lasts years, not months.

The downside is application time. Several coats with drying time between each. And it needs refreshing every year or two even in good conditions. But still better than constant oil maintenance.

Deck Stains

Specifically designed for horizontal outdoor surfaces that get walked on. They come in semi-transparent versions that show grain or solid versions that look more like paint.

I prefer semi-transparent for nice wood and solid for ugly wood I want to hide. Both work well on decks, which are basically the toughest outdoor wood application there is.

Look for products with mildewcide included. Mold and mildew love outdoor wood, especially in humid climates. An ounce of prevention beats scrubbing green gunk every spring.

Epoxy

For maximum protection, nothing beats epoxy. It creates a complete seal – waterproof, incredibly durable, fills gaps and cracks. I use it on outdoor table tops that I want to last forever.

But epoxy has issues. It is finicky to apply. It yellows in direct sunlight unless you use marine-grade stuff with UV protection. And it is expensive compared to other options.

Also it looks very shiny and plastic-y. If you want natural wood aesthetics, epoxy is not it. It is more for pure protection than beauty.

What I Actually Do

For most outdoor furniture, I use marine spar varnish. Three or four coats on all surfaces including undersides. Let each coat cure fully before the next – usually 24 hours minimum.

Prep matters a lot. Sand everything smooth, 120 through 220 grit. Clean off all dust. Apply in moderate temperatures – not too hot, not too cold, not humid. Read the can for specifics.

I refresh the finish every spring before the season starts. Light sand with 320 grit, wipe clean, one or two fresh coats. Takes an afternoon and keeps everything looking good.

UV Protection is Critical

Sunlight destroys wood. Not just the finish, the actual wood fibers. That gray color on old decks and fences? That is UV damage. The wood is literally breaking down.

Any outdoor finish should have UV blockers or stabilizers. Check the label. Products without UV protection will fail faster and the wood underneath will degrade.

This is especially important on horizontal surfaces that get direct sun. Vertical surfaces in shade can get away with less UV protection. But why take chances.

Dealing with Moisture

Water is the other big enemy. It swells wood, promotes rot, encourages mold. Every outdoor finish is trying to keep water out.

Penetrating oils create water resistance in the wood fibers. Film finishes create a barrier on the surface. Both approaches work, but surface finishes generally perform better in my experience.

The tricky part is that wood needs to breathe somewhat. A finish that traps moisture inside can actually cause problems. That is why spar varnish is designed to stay flexible – it allows some moisture movement without cracking.

Maintenance is Not Optional

Outdoor finishes need attention. Even the best ones. If you are not willing to refinish periodically, consider plastic or metal furniture instead.

I inspect my outdoor pieces every spring. Look for cracks in the finish, gray spots, soft areas that might indicate moisture problems. Address issues early before they become big problems.

Store what you can during harsh winters. Or at least cover it. Less weather exposure means less maintenance.

The Realistic Takeaway

There is no magic outdoor finish that lasts forever with zero maintenance. Anyone who tells you otherwise is selling something.

What you can do is pick appropriate products, apply them correctly, and stay on top of maintenance. Do that and outdoor wood projects can last decades. Skip any of those steps and you are buying new furniture sooner than you wanted.