Outdoor Furniture Finishing: A Comprehensive Guide

Outdoor Furniture Finishing: A Comprehensive Guide

When I was a kid, my dad made a pair of Adirondack chairs that sat out front of the old farmhouse where I grew up. Looking back, they added a charming, rustic touch to the house. They were attractive pieces, but over time, the finish began to peel. As other priorities took over, refinishing the chairs was repeatedly postponed. Years passed, and they slowly turned gray and cracked. Today, those chairs remain—battered, weathered, and colorless—just outside the door.

That memory has stayed with me, and as a furniture maker, I’ve been determined to avoid watching my own outdoor projects succumb to the elements. Fortunately, there are reliable options for outdoor finishing that can protect furniture and preserve its beauty, offering peace of mind and longevity.

What Makes an Outdoor Finish Special?

The primary difference between outdoor and indoor finishes lies in the additives that protect against the unique challenges of the outdoors. Left untreated, wood exposed to the elements turns into a rough, gray mess over time. The primary culprits are:

1. Fungi: Mold and mildew can break down wood over time.
2. Moisture: Rain, humidity, and dew can cause rot and swelling.
3. UV Damage: Prolonged exposure to sunlight degrades the wood’s color and surface integrity.

While these forces can’t be entirely avoided, careful planning and the right finish can significantly mitigate their effects.

Types of Outdoor Finishes

Outdoor finishes typically fall into three categories: paint, film-forming finishes, and penetrating oils. Each offers unique benefits depending on your project’s needs.

1. Paint

Paint remains one of the most practical and protective options. Exterior-grade paints contain UV inhibitors and mildewcides, providing a thick, durable barrier against the elements. They’re also available in virtually any color, offering unlimited design possibilities.

• Application: Most modern exterior paints combine coating and primer for easier application. Simply clean the surface, apply a few coats, and allow them to dry.
• Drawbacks: Paint conceals the natural grain of the wood, which may not suit every aesthetic.

2. Film-Form Finishes

Film-forming finishes, such as spar varnish, exterior polyurethane, and deck sealers, create a transparent or semi-transparent barrier over the wood. These finishes allow the wood’s natural beauty to shine through while offering protection against UV rays and moisture.

• Application: Apply an even coat with a brush, let it dry, and sand lightly between coats. Several coats are usually required for optimal protection.
• Lifespan: These finishes typically last three to five years before requiring reapplication.
• Considerations: Over time, the finish may peel or wear down. Refinishing involves completely sanding off the old finish, which can be labor-intensive.

3. Penetrating Oils

Penetrating oils, such as teak oil or tung oil blends, soak into the wood to provide protection from within. These finishes are mixed with UV inhibitors, water repellents, and mildewcide to prevent graying and rot.

• Application: Brush, roll, or wipe the oil onto a clean, sanded surface, allowing it to soak in before wiping off excess. Two to three coats are usually sufficient.
• Lifespan: Penetrating oils require annual reapplication, but the process is quick and straightforward.
• Advantages: Unlike film-forming finishes, penetrating oils don’t peel, making maintenance easier.

Choosing the Right Materials

Wood Selection

Material choice is crucial for outdoor projects. Some woods naturally resist moisture, rot, and pests, making them ideal for outdoor furniture.

• Domestic options: cedar, redwood, white oak, and cypress.
• Exotic options: Teak and ipe offer unparalleled durability thanks to their dense fibers and natural oils.

While no wood is entirely immune to weathering, these species provide a strong foundation for lasting outdoor pieces.

Adhesives and Hardware

Outdoor furniture requires adhesives and hardware that can withstand the elements.

• Adhesives: Use waterproof options like two-part epoxy, polyurethane glue, or waterproof PVA glue. These adhesives ensure a resilient bond even in wet conditions.
• Hardware: Opt for stainless steel or coated screws and bolts to prevent rust and staining.

Enhancing Durability with Epoxy

Epoxy can extend the life of outdoor finishes, a technique borrowed from shipbuilding.

• Under Finish: Apply an epoxy coating before painting or varnishing to harden the wood fibers and enhance durability.
• End-Grain Protection: Create an epoxy “shoe” around the foot of furniture to seal and protect end grains from moisture wicking.
• Filling Cracks and Knots: Pour epoxy into cracks or imperfections before sanding for a smooth, sealed surface.

While epoxy adds cost, it can be a worthwhile investment for high-exposure projects.

Letting Nature Take Its Course

For those who prefer a weathered look, certain woods age gracefully without any finish. Cedar, redwood, Ipe, and teak develop a natural gray patina over time, creating a rustic aesthetic reminiscent of old barns and farmhouses. While these pieces will eventually wear, their natural charm can be well worth the trade-off.

Final Thoughts

Protecting outdoor furniture requires thoughtful planning and the right materials. Whether you opt for the vibrant protection of paint, the clear sheen of film-forming finishes, or the simplicity of penetrating oils, the goal remains the same: to create pieces that endure the elements with style and grace.

And for those Adirondack chairs of my childhood? Perhaps their weathered look isn’t such a bad thing after all. Their durability serves as a testament to the enduring quality of good craftsmanship, regardless of material changes.