Preparing wood for staining is just as important as staining itself. Good prep work leads to a finish that looks great and lasts longer. When you take time to prepare wood properly, the stain soaks in evenly and provides better protection against the sun, rain and daily wear. Different types of wood and different outdoor conditions may need slightly different approaches. Even old, gray wood can look fresh and new again with the right preparation steps. Follow these essential steps to ensure your exterior wood surfaces are ready for staining.

Before you start prepping, inspect your project for damage and imperfections, especially if you're restoring an older structure. After cleaning the wood, anything you find will need to be addressed.

Rot is soft, discolored or crumbling wood that compromises wooden structures, even after staining. Any badly rotted boards need to be completely replaced to prevent rot from spreading. 

Fill minor imperfections like cracks, splits and holes with a stainable, exterior-grade wood filler designed for outdoor use. Apply the filler with a putty knife, slightly overfilling the damaged area. Once dry, sand the repair flush with the surrounding wood for a smooth, even surface that will accept stain uniformly.

Remember that wood fillers may accept stains differently than the surrounding wood. Test your stain on repaired areas in an inconspicuous spot to ensure the color match is acceptable. Alternatively, you can stain the wood first, then fill any minor imperfections with a color-matched filler for a more seamless appearance.

Some woods, particularly pine and cedar, may have areas where sticky resin or sap has seeped out. Carefully scrape away this excess resin using a plastic scraper to avoid damaging the wood. Then, clean the area thoroughly with rubbing alcohol or methyl hydrate on a clean cloth. This will dissolve the remaining residue that could interfere with stain absorption.

Lastly, check for any loose or protruding nails and fasteners. Reset or replace these as needed and fill any abandoned nail holes with wood filler. Repair larger structural issues like warped boards or loose railings before proceeding with the staining process.

Now that we've covered possible damage you may encounter before staining, let's discuss the process of prepping wood for stain. Wood type is an essential factor when preparing wood for stain, but the condition of the wood is just as critical as it can alter the steps you take before staining.

New wood may appear ready for staining, but preparation is required to ensure even staining and sealing. Start by cleaning thoroughly to remove mill glaze, dirt and natural debris using a quality wood cleaner formulated explicitly for new wood. Rinse thoroughly with clean water and allow it to dry completely, which may take several weeks, depending on the wood type and weather conditions.

Next, sand lightly in the direction of the wood grain using medium-grit sandpaper (120-grit works well). This opens the wood pores for better stain absorption. Remove all sanding dust with a tack cloth or vacuum before proceeding.

Timing is crucial when working with new wood. Staining untreated lumber shortly after installation is best to help prevent wood deterioration, darkening or mildew growth from exposure to the elements. However, beware of staining treated (green) wood too early. Before applying the stain, give the wood time to "leach out" tannins and other treatment substances.

This process typically takes 3-6 months in warm, dry climates and potentially 9-12 months in cooler, wetter regions. While leaching continues for years, it significantly reduces after this initial period, making it safe to apply stain. Consult with Sherwin-Williams experts or your lumber supplier about optimal timing for your specific climate and wood type.

If your wood has a failing finish, you'll need to remove the old finish using a quality stain stripper to break down previous coatings. Follow with a wood cleaner to remove any residue. Lightly sand any stubborn areas with 120-grit sandpaper.

After cleaning, address any damage by replacing severely rotted boards and filling cracks and holes with exterior-grade wood filler. Sand repaired areas smooth once dry. Don't forget to caulk around windows and doors to create a proper seal.

If you're restoring a fence, deck or other wooden outdoor structure, you must address the common signs of aging. If you encounter mold or mildew, treat it first using a solution of one part bleach to three parts water. Apply to affected areas and allow to sit for 10-15 minutes before rinsing thoroughly and allowing to dry completely.

After treating mold or mildew, apply a wood brightener/restorer to lift the grey color and revitalize the wood's appearance.

Wood must be completely dry before you can start staining. Test the wood by sprinkling water on the surface. If it absorbs quickly, the wood is ready. Before committing to a full application, test your stain on an inconspicuous area and allow it to dry to confirm the color meets your expectations.

Once you're happy with your stain color, planning your project around the weather will be important to a successful staining project. Choose a day with moderate temperatures (50-90°F) and no rain in the forecast for at least 24 hours. Protect surrounding areas by spreading drop cloths to shield your foundation, walkways, shrubs, and plants from accidental spills.

Mix the stain thoroughly before and occasionally during application to maintain consistent color. When working on large projects, tackle manageable sections you can complete without interruption. Different wood species absorb stain differently, so adjust your approach accordingly. Make any necessary adjustments to your technique or product selection before proceeding with the project.

Purchasing or renting a pressure washer can significantly accelerate the wood preparation process, especially when restoring weathered or painted wood. For efficient cleaning, select a pressure washer with 1500-2000 PSI for softwoods like cedar or pine, and up to 2500 PSI for harder woods like oak. Always maintain a distance of at least 12 inches from the wood surface and use a fan tip (typically 40-60 degrees) to prevent damaging the wood fibers.

Pressure wash the wood in the direction of the grain in smooth, overlapping strokes to remove dirt, mildew and loose fibers while preserving its integrity. For stubborn areas, you may need to use a wood cleaner and pressure wash the area again. Allow the wood to dry before applying the wood cleaner for best results.

After pressure washing, allow the wood to dry thoroughly—typically 48-72 hours in good weather conditions—before staining. Remember that while pressure washing speeds up cleaning, it also opens the wood grain and may raise some fibers, so light sanding after drying is necessary for a smooth finish.

Minimize the appearance of sand marks by working your way down to fine-grit sandpaper in progressive stages. Start with coarser grits (80-100) only if the wood is rough or has significant imperfections. For most exterior projects, begin with medium grit paper (120-150) to remove minor surface flaws and old finishes while opening the wood grain for better stain penetration. Once the surface is uniform, switch to fine grit sandpaper (180-220) for the final pass, which removes the scratches left by the previous grit and creates a smooth, even surface that will accept stain beautifully.

Always sand in the direction of the wood grain, never against it or in circular motions, as cross-grain sanding creates noticeable scratches that become more visible after staining. Between grit changes, wipe the surface with a tack cloth or vacuum thoroughly to remove dust particles that could interfere with your progress. Consider renting a floor sander for large projects like decks to save time and ensure consistent results. Always wear a protective dust mask and safety glasses to protect yourself from airborne wood particles throughout the sanding process.

Now that you've prepped your exterior project, it's time to get your stain. Calculate how much stain you need with a tape measure and simple math.

1. Measure the length and height of each surface to be stained. For rectangular areas like deck floors or fence sections, multiply the length by the width to find the square footage. For irregular shapes, break them down into rectangles and triangles, calculate each separately and add them together.
2. Divide the square footage by the coverage rate listed on your stain product. Most exterior wood stains cover 150-300 square feet per gallon on the first coat, depending on wood porosity and stain type. Rough or weathered wood absorbs more stain, reducing coverage to the lower end of this range. Smooth or dense woods may achieve the higher end of coverage.
3. Add 20% to the total for waste, spillage and touch-ups. If your total is between gallons, round up to the next fullgallon.

For example, if your deck measures 400 square feet and your chosen stain covers 200 square feet per gallon:

• 400 ÷ 200 = 2 gallons
• Plus 20% (0.4 gallons) = 2.4 gallons
• Round up to 3 gallons to ensure you have enough

Remember that second coats (if recommended by the product) typically require less stain than the first coat, as the wood is less absorbent after the initial application. For these subsequent coats, expect to use about 70-80% of what the first coat required.

Now that your surface is properly prepared, it's time to bring your vision to life with our selection of exterior stains. Purchase everything you need online and pick it up in-store, or schedule delivery to your door.

For professional staining results, check out our tutorial on applying exterior stain.