Pressure treated wood requires careful cleaning to maintain its appearance and longevity without harming the wood or finish. This guide provides practical, step-by-step instructions using common tools and products to safely restore deck or fencing made from pressure treated lumber.
Quick Answer
For best results, use a power washer within a safe PSI range (typically 2000–3000 psi for wood decks), apply a deck cleaner concentrate, scrub with a long-handled brush, and finish with a wood brightener. Always start with the gentlest method and test on a small area first.
What You’ll Need
- 2000-3000 psi pressure washer for wood deck cleaning
- deck cleaner for pressure treated lumber concentrate
- deck scrubbing brush long-handled for wood cleaning
- soft wash spray nozzle for pressure washer wood cleaning
- wood brightener and cleaner kit for pressure treated decks
Before You Start
Assess the wood condition: if boards show warping or loose nails, address those issues first. Protect surrounding plants and surfaces with plastic sheeting. Wear eye protection, gloves, and a respirator if working near dusty surfaces. Never use a harsh bleach solution on untreated wood as it can damage fibers and cause color loss. Plan for multiple passes and allow adequate drying time between steps.
Time estimate: 2–6 hours depending on deck size and level of staining. Weather conditions should be dry and mild; avoid cleaning on very hot days or when rain is likely.
Step-By-Step: How To Clean Pressure Treated Wood
- Prepare the area and assemble equipment. Attach the soft wash spray nozzle to the pressure washer and connect the deck cleaner concentrate according to the manufacturer’s directions.
- Protect nearby plants and outlets. Remove furniture, grills, and rugs; cover any electrical outlets or switches on or near the deck.
- Test a small area. Apply the cleaner to a discreet patch to confirm it won’t cause unwanted color change or damage.
- Apply the cleaner to the wood. Follow the product directions for dilution and application method. Let the cleaner dwell for several minutes to loosen dirt and tannins.
- Agitate with the long-handled deck scrubbing brush. Work in direction of the wood grain, focusing on heavily stained areas but avoiding aggressive scrubbing that could roughen surfaces.
- Rinse with the pressure washer on a low-pressure setting. Use broad, sweeping motions and keep the nozzle at a safe distance to prevent gouging or etching the wood.
- Assess staining and repeat if necessary. For stubborn areas, reapply cleaner and gently scrub before rinsing again.
- Apply wood brightener if the manufacturer recommends it. Rinse thoroughly after the prescribed dwell time to restore color and enhance natural tones.
- Dry thoroughly before reintroducing furniture or applying any sealant. Allow 24–48 hours of drying time in ideal conditions.
- Clean the equipment after use. Rinse all hoses, nozzles, and brushes to prevent buildup and prolong tool life.
Troubleshooting
| Symptom | Likely Cause | Fix | Prevention |
|---|---|---|---|
| Streaks or uneven color | Uneven cleaner dwell or insufficient rinse | Reapply cleaner to affected areas and rinse thoroughly | Test patch; follow dwell times precisely |
| Wood fibers raised or rough | Over-aggressive scrubbing or high pressure | Switch to moderate pressure; use soft brush | Keep pressure and brush movement gentle |
| Residual staining after rinse | Deep tannins or mineral deposits | Reapply with longer dwell time or brighten according to product | Work in smaller sections for control |
| Excessive color loss | Harsh cleaner or improper dilution | Rinse immediately and dilute cleaner next time | Follow manufacturer guidelines |
Common Mistakes
- Using too high a PSI on soft-treated wood, which can gouge fibers or wear down grain.
- Skipping a test patch or dwell time, leading to unexpected color changes.
- Aggressive scrubbing that abrades the surface; gentler scrubbing is usually sufficient.
- Not protecting surrounding plants or failing to rinse off cleaner completely.
- Neglecting drying time before reassembly or sealing.
Tips For Best Results
- Work with the grain when brushing to reduce fiber raise and uneven appearance.
- Choose a deck cleaner concentrate formulated for pressure treated lumber; some blends are tailored for tannin removal.
- Test cleaning products on a hidden area first to confirm color fidelity.
- After brightening, apply a color-enhancing or protective sealant as recommended for best long-term results.
- Temperature and humidity affect drying time; plan accordingly if rain is forecast.
Call A Professional
Consult a professional if the wood shows extensive rot, loose boards, warping, or insect damage. Stop cleaning if you notice cracking, splitting, or sudden soft spots. A pro can assess structural integrity and recommend restoration or replacement options.
FAQ
Should I use a household pressure washer to clean pressure treated wood?
Yes, a machine in the 2000–3000 psi range is generally suitable for decks; avoid pressures higher than necessary to prevent surface damage.
Can I use bleach to clean pressure treated wood?
Bleach can be effective for stain removal but must be used carefully and diluted properly to avoid damaging the wood or nearby plants.
Do I need to seal after cleaning?
Sealing after cleaning helps protect against moisture and UV damage. Allow complete drying before applying a sealant.
How long does it take for pressure treated wood to dry after washing?
Drying time varies with humidity and temperature but typically ranges from 24 to 48 hours.
Can I stain or paint immediately after cleaning?
Staining or painting is best after the wood is fully dry; follow the stain or paint manufacturer’s instructions for prep.
Buying Guide
Key buying factors for cleaning pressure treated wood include size and layout of the area, noise tolerance, and compatibility of cleaning products. Consider a pressure washer capable of delivering sufficient cleaning power without risking damage to wood surfaces. For routine maintenance, a deck cleaner concentrate paired with a wood brightener kit can streamline care. A long-handled scrubbing brush reduces bending versus handheld tools, while a soft spray nozzle helps protect delicate fibers. When evaluating kits, ensure the products are formulated for pressure treated lumber and provide clear instructions for dwell times and dilution. Placement of the equipment—away from the home and with proper drainage—helps maintain safety and efficiency. If the project involves extensive staining or restoration, factor in potential professional assistance for best results.