Should You Wash Your Deck After Sanding?

Dec 20, 2023

If you’re considering refinishing your outdoor deck, sanding is an essential part of the preparation process. Proper cleaning and washing post-sanding helps remove debris, opens wood pores for staining, and improves finish adhesion. This article will cover when and how to effectively wash your deck after sanding to guarantee optimal results.

Deck refinishing projects start with sanding to remove old finishes, smooth and flatten surfaces, and prep the wood for new protective coats of stain, paint, or sealers. Sanding uses abrasive materials to “rough up” deck boards by removing splintered, cracked wood fibers and erasing the gloss of previous applications.

While sanding is abrasive by nature, washing afterwards serves important functions:

  • Removes all sanding debris and wood dust from cracks and crevices
  • Opens wood pores and fibers for penetration and adhesion of new finishes
  • Allows you to inspect condition and spot potential problems before restaining
  • Improves finish bonding and extends overall life of renewal efforts

Proper post-sanding washing takes more than just a cursory rinse. To unlock the full benefits, you need the right process, timing, tools, and deck wash formula. Keep reading to learn when and how to wash your deck after sanding.

What is Deck Sanding?

Deck restoration starts by using manual or power sanders to remove failing stains, flatten warped planks, and smooth away splinters and grayed wood fibers. Professionals rely on random orbital sanders, while DIYers often use palm or belt sanders.

Sandpaper grades range from coarse (24-40 grit) to very fine (80-120 grit). Low grits aggressively remove material, higher grits smooth surfaces. The grade sequence you use depends on your deck’s initial condition.

Deck Sanding

Residential decks are commonly made from softwoods like pine, cedar, redwood, and fir. All are porous and prone to cracking, cupping, and fungus or mold growth when left unprotected from sun, rain, snow and foot traffic. Refinishing restores beauty, while new stain or sealer coats provide UV and moisture resistance.

Why Proper Post-Sanding Washing Matters?

Freshly sanded wood looks clean to the naked eye. But micro debris lingers everywhere, especially in crack and cuts. Any remnants left behind can ruin your refinishing results and waste hours of work.

Wood dust, dirt, and particles act as barriers that block absorption of new protective finishes. They also reduce adhesion, contributing to premature failure as flaking or peeling. That’s why a simple rinse or hose-down is never enough post-sanding.

Further, washing opens pores and fibers to accept penetrating or film-building coatings. Cleaner application surfaces enhance bonding strength. That means finishes last longer, providing more durable protection from weathering.

When to Wash Your Deck After Sanding?

Ideally, you should wash your sanded deck immediately before applying renewing finishes. Same day is best. Cleaned wood needs to fully dry, which takes 24-48 hours in ideal conditions.

At Floor Sanding, we recommend cleaning no more than 2-3 days prior. Any longer allows airborne contaminants like pollen or dirt to resettle. It also gives mold spores a chance to take hold in opened wood cells.

Washing months before refinishing defeats the entire purpose. Over time, UV exposure and oxidation will start closing the pores that cleaning opened. Adhesion issues are likely again.

How to Wash Your Deck Properly After Sanding?

Proper sanded deck washing takes the right process, cleaning mixture, tools and some elbow grease. Here is a step-by-step guide:

How to Wash Your Deck Properly After Sanding

Supplies Needed

  • Garden hose with pressure nozzle
  • Stiff bristle push broom
  • Heavy duty deck cleaning solution
  • Scrub brush for tight spots
  • Power washer (optional)

Step 1 – Sweep First

Use a push broom to remove all loose debris and surface dust left from sanding. Sweep both directions to reach into corners and under railings. Discard debris completely before wet washing.

Step 2 – Mix Cleaning

Solution Fill a pump sprayer with heavy duty deck cleaner according to label directions. Look for formulations with sodium metasilicate, oxalic acid or sodium hydroxide to break down tannins, mold stains, mildew and deeply ground cellulose and lignin.

Step 3 – Pre-rinse with Garden Hose

Lightly pre-wet deck with a garden hose on fan spray setting. This prevents cleaning solutions made for wood from drying too fast.

Step 4 – Apply Deck Wash Liberally

Apply your mixed solution gradually over all decking using a downstream motion. Completely saturate the surface, but avoid excessive puddling. Let it dwell 5-10 minutes.

Step 5 – Scrub Entire Deck

Vigorously scrub all areas with a stiff push broom, rotating bristles often to reach into wood pores. Use a hand scrub brush to target ground-in grime on knots, cracks and edges. Rinse brush bristles frequently.

Step 6 – Power Rinse Clean

Rinse thoroughly with a pressure nozzle garden hose on a fan spray setting. For optimal results, follow up with a power washer under 2500 PSI at 12-18 inches away. Let the deck dry completely over 48 hours before refinishing.

Other Effective Deck Cleaning Alternatives

While post-sanding deck washes use water and cleaning concentrates, other effective alternatives exist:

Oxalic Acid

Oxalic acid solutions help brighten weathered gray wood fibers and remove tannins, water marks, iron stains or alkali salts. Rinse thoroughly after dwell times up to 15 minutes.

Sodium Bicarbonate (Baking Soda) Blend

Baking soda-based mixes provide gentle cleaning for lightly soiled decks. Dwell times are 1 hour or more. Rinse off thoroughly.

Hydrogen Peroxide Mix

Hydrogen peroxide breaks down organic material without harsh chemicals. Apply, let sit 30-60 minutes based on product directions, scrub and rinse away.

Deck Wash Pros from Floor Sanding

At over 10 years serving London and surrounding areas, we are the experts in sanding and refinishing all wood floors and decking.

After full sanding services, take advantage of our professional post-sanding deep cleaning using industrial mix solutions, pressure washers and experienced technicians.

Proper cleaning is vital for stunning refinish results that stand the test of time and foot traffic. Contact us for a free quote or more information about revitalizing your lackluster deck this season.

Why Hiring Professional Floor Refinishing


Sanding is the starting point of any deck restoration project, while washing afterwards completes the preparation process. Thorough cleaning removes barriers to finish adhesion while opening wood pores for accepting new protective coats of stain or sealer.

Always wash a freshly sanded deck before refinishing using the right deck cleaning solutions, tools and rinsing methods. Allow 48 hours to dry fully. Proper post-sanding washing techniques lock in durability and longevity of your renewed outdoor living space.


After Sanding Do I need to wash my deck if I’m just applying clear sealer?

Yes, washing after sanding is equally important before new coats of clear sealers. Any debris or particles trapped under the film finish can detract from appearance and lead to premature breakdown or failure over time.

What’s the best way to dry my deck fast after washing?

Letting your deck dry naturally over 48 hours is ideal and allows complete evaporation. If faster drying is essential, use fans rigged above the deck blowing air across boards. Avoid heat methods that may warp planks.

Can I pressure wash instead of hand scrubbing?

Yes, power washing under 2500 PSI with a fan tip nozzle 12-18 inches away provides superior cleaning results after pre-treating. Adjust pressure downward for softwoods like cedar and pine to avoid surface damage.

How soon can I apply stain or sealer after washing?

Lightly sanded and washed decks need about 48 hours to fully dry in ideal conditions before applying water or oil-based finishes. Hot, arid climates may dry faster while cool, humid areas take longer. Always test moisture levels.

Does wood have to weather after sanding and cleaning?

Ideally, freshly exposed wood should weather 7-14 days before finishing. This stabilizes moisture content and allows UV exposure to neutralize tannins and sugars that can interfere with adhesion. However, thorough post-sanding washing mitigates these issues.