Staining and sealing outdoor wood is an important process to help protect and preserve your wood projects. Properly preparing and treating the wood will allow it to better withstand exposure to sun, rain, snow, and other elements. Here is a comprehensive guide on how to stain and seal wood for outdoor use.
Introduction
Outdoor wood projects such as decks, fences, pergolas, and furniture need special protection to prevent cracking, splintering, warping, and other damage from moisture and UV rays. Using quality wood stains and sealers is key to maintaining the beauty and integrity of your wood.
When wood is left unfinished outdoors, its color will fade to a weathered gray over time. Regular staining gives wood a protected, vibrant, and consistent color. Clear wood sealers provide a defensive barrier against moisture damage.
By properly staining and sealing, you can keep your outdoor wood looking great for years while also extending its lifespan. This guide will walk you through the complete process.
Benefits of Staining and Sealing Outdoor Wood
Staining and sealing outdoor wood provides the following advantages:
- Enhanced Appearance – Stain adds rich, translucent color that brings out the natural beauty in wood grain. Clear sealers enhance the stain while allowing the texture to show through.
- UV Protection – Sealers contain UV inhibitors that reduce damage from sun exposure, slowing down discoloration and wood fibers from breaking down.
- Water Resistance – Sealers guard against moisture penetration, which can cause swelling, cracking, and rotting of wood.
- Resists Mold and Mildew – Stained and sealed wood is less prone to attracting and retaining mold spores.
- Easier Maintenance – Routine cleaning and reapplication of stain/sealer is easier than more intensive repairs if wood is left unprotected.
- Longer Lifespan – The right combination of stain and sealer can double or triple the usable life of outdoor wood projects.
How to Prepare Wood for Staining and Sealing
Proper preparation is the first critical step to ensure the finish adheres well and lasts. Here is how to get wood ready for staining and sealing:
Clean the Surface
Use a brush and concentrated wood cleaner to remove dirt, mold, mildew stains, and other debris. Rinse thoroughly. Allow the wood to completely dry for at least 24 hours.
Sand the Wood
Lightly sand to smooth any rough areas and remove splinters/fibers raised from weathering. Use 80-120 grit sandpaper and go with the direction of the wood grain.
Repair Damage
Inspect for any cracks, holes, rotted areas, or other flaws. Make repairs using wood filler, caulk, or epoxy before staining.
Remove Existing Finish
If re-staining wood that already has old stain or sealer, you’ll need to completely strip it first. Use a chemical stripper or power washer, then sand once stripped.
Pro tip: Wear proper eye and skin protection when preparing wood.
How to Choose a Stain and Sealer
With preparation complete, it’s time to select quality products that suit your project:
Types of Stain
- Oil-based – Offers deeper color penetration into wood grain. Longer-lasting and provides good UV resistance.
- Water-based – Lower odor, easier cleanup, and faster drying than oil. Not as durable.
- Gel stains – Thicker consistency stays only on the surface to highlight grain. Good for uneven surfaces.
- Opaque stains – Contain more pigment to totally obscure wood grain with an opaque tint.
- Transparent stains – Allow more of the natural wood grain to show through. Recommended for outdoor use.
Types of Clear Sealers
- Oil-based varnish – Most protective finish against moisture and sun damage. Requires mineral spirits for cleanup.
- Spar varnish – Formulated for outdoor use. Provides excellent protection from elements.
- Polyurethane – Durable synthetic resin seals against moisture. Oil-based versions offer better longevity than water-based.
- Water sealers – Penetrating water-repellent finishes that are lower odor and easy cleanup with water. Not as long-lasting as other sealers.
- Epoxy resin – Extremely durable two-part finish provides moisture barrier and UV resistance. Used on countertops or high-wear areas.
Tips for Product Selection
- Check product labels to confirm suitability for outdoor use. Look for “exterior,” “outdoor,” or “weather/water resistant.”
- Select oil-based options for longer performance exposed to sun and rain.
- Match oil-based stains with oil-based sealers for best adhesion. Do the same for water-based products.
- Consider eco-friendly milk paints, citrus solvents, or food grade oils as natural stain options.
How to Apply Wood Stain
Once you have selected products suitable for outdoor staining, follow these steps for application:
1. Stir Stain and Read Directions
Mix oil-based stains well before using. Read the product directions to understand dry times, number of coats needed, cleanup instructions, and other specifics.
2. Wear Protective Gear
Use gloves and eye protection when working with stains. Cover any nearby plants/furniture to avoid overspray. Use drop cloths under the wood.
3. Test Stain on Inconspicuous Area
Apply a bit of stain in a hidden spot to confirm the color and appearance before staining the entire surface.
4. Use a Brush, Pad, or Sprayer
Apply stain smoothly and evenly using the appropriate applicator. Avoid drips or thick buildup in grooves.
5. Wipe and Distribute the Stain
As you apply, wipe gently across the grain with a clean cloth to spread and even out the stain. Remove any excess for a smooth look.
6. Coat End Grain Twice
The end grain of boards absorbs more stain and needs extra attention. Brush stain on ends, let sit 5-10 minutes, then reapply.
7. Allow Proper Dry Time
Let the stain cure fully according to manufacturer directions before adding another coat or sealing.
How to Apply a Clear Wood Sealer
Once the stain has cured following the directions above, use these steps to apply the protective clear topcoat:
1. Lightly Sand Stain
Use 220 grit sandpaper to gently smooth any “grain raise” on the stained wood before sealing it. Dust off completely after sanding.
2. Vacuum and Tack Cloth
Use a vacuum and then a tack cloth to thoroughly remove dust from the surface before sealing.
3. Read Sealer Directions
Follow manufacturer instructions for application, dry time, number of coats, cleanup, and any precautions.
4. Apply Sealer with Brush or Roller
Use a high-quality natural bristle brush, lambswool applicator, or microfiber roller. Apply sealer coats smooth and even to fully coat surfaces.
5. Maintain Wet Edges
As you apply the sealer, maintain a wet edge to prevent lap marks. Blend sections together.
6. Allow Proper Curing Time
Let sealer dry thoroughly between coats according to label directions. Some sealers take 24 hours or longer to cure.
7. Apply Second Coat if Needed
For optimal protection, apply two thin sealer coats instead of one thick coat. Sand very lightly between coats.
8. Allow Final Cure
Give the sealer several days to fully harden before placing furniture on it or using the wood surface.
How to Maintain Outdoor Wood Finishes
To keep your stained and sealed outdoor wood looking beautiful over years, follow these maintenance tips:
- Inspect regularly for any worn, cracked, or peeling areas in the finish. Make touch up repairs quickly to prevent moisture damage.
- Reapply fresh sealer coats every 1-2 years to reinforce protection, or whenever water is no longer beading on the surface.
- Clean finished wood once or twice per year with a deck cleaner or mild soap and water. Avoid abrasive cleaners.
- Lightly sand and re-stain outdoor wood every 2-4 years to keep the vibrant color. Strip and re-finish if stain stops adhering or excessive cracking/peeling occurs.
- During winter months, keep wood surfaces free of standing snow and ice accumulation, which can damage the finish.
- Consider re-staining decorative outdoor wood projects like planters or Adirondack chairs annually for a fresh pop of color.
Tips for Success Staining and Sealing Outdoor Wood
Follow these tips to get the best results from your staining and sealing project:
- Always test products in a small hidden area first to ensure compatibility and appearance.
- Apply products on a dry day with temps between 50-90°F as recommended on labels. Avoid staining in direct sun.
- Use high quality application tools – stained brushes for oil, foam brushes for water-based, and microfiber rollers.
- Thin multiple sheer coats often provide better protection than one thick coat.
- Give adequate dry time between steps for best adhesion. Rushing can ruin the finish.
- Dispose of oil-based products properly. Allow rags to dry before disposal to prevent combustion.
- Work in manageable sections, completing one full step across the entire surface before moving to the next step.
Conclusion
When finished properly using the right products, staining and sealing outdoor wood can protect it from UV rays, excess moisture, mold, and other damage. This allows your wood projects to maintain structural integrity and aesthetic appeal for many years of enjoyment.
Be sure to prepare the wood surface adequately, choose compatible stain and sealer formulations, apply them correctly, and perform routine maintenance. Your resulting stained and sealed outdoor wood will showcase beautiful, enduring color that stands up to the elements.