Fall Deck Cleaning: Your End-of-Season Checklist

There’s been a shift in the air — cooler mornings, earlier sunsets, and the feeling that another Pacific Northwest fall has arrived. As the seasons change, fall is the perfect time to give your deck a good cleaning before winter comes, and the gray skies and rain settle in.

Now is a great time to set aside a couple of hours to refresh your deck, which can go a long way toward protecting it during the winter and making it easier to start next spring. Whether your deck is made from cedar, hardwood, softwood, modified wood, or composite materials, the principles stay the same: clean it thoroughly, inspect it properly, and treat it appropriately.

Why Now is the Right Time.

Waiting until spring to clean your deck might seem handy, but by then, you face months of trapped moisture, moss, mildew, and discoloration. A pre-season clean clears away grime and organic buildup while the weather is still dry enough to dry properly and apply products. It also gives you a chance to identify any repairs needed before freeze-thaw cycles exacerbate the problem.

In short: a little work now can extend the life of your decking — and keep it looking its best all year long.

Start with the Basics: Sweep and Wash

Start by clearing off furniture, planters, and debris. Then, sweep the deck thoroughly to remove leaves, twigs, and surface dust. After that, you have a few options depending on how deep a clean your deck needs.

• Light cleaning: Mix warm water with TSP (trisodium phosphate), a trusted, no-frills deck cleaner that cuts through grime. Use a stiff, yet gentle scrub brush or broom to work it into the wood and then rinse thoroughly with a hose.
• Deeper cleaning: If you see mildew, dark stains, or the silvering, weathered look of UV damage, consider using a specialized wood cleaner like CUTEK® Quickclean. It’s a biodegradable, wood-safe option that works well on both hardwoods and softwoods.
• Pressure washing: Although tempting, it should be used with care. Too much pressure can damage wood fibers, especially on softer species like cedar.

💡Tip: Allow your deck to dry thoroughly (typically 24–48 hours) before applying any finishing products.

Tackle Stains and Prep for Finishing

Once your deck is clean and dry, take a closer look. Do you see deeper and darker spots or moldy patches and tannins still bleeding through? These deeper discolorations need more than a light cleaning, and this is where wise product choices make a big difference.

Skip the Bleach (it does more harm than good)

While it’s tempting to reach for bleach, doing so can damage your wood. Bleach is harsh and corrosive — it can harm wood fibers, weaken metal fasteners, and harm surrounding landscaping. Even worse, it often leaves uneven results and doesn’t penetrate deeply enough to remove embedded stains.

Instead, use targeted wood restoration products made for the job:

• Brighteners and tannin removers help lift organic stains and restore color consistency
• Stain strippers remove old finishes or oils so the wood can properly absorb new protection

These products are designed for wood — they clean effectively without stripping or damaging, so the surface remains strong and prepared for whatever comes next.

 Inspect and Maintain

Cleaning is also a great time to check the details:

• Tighten or replace loose screws and nails
• Inspect railings, stairs, and joints for wear or shifting
• Clear out gaps between deck boards to ensure water runoff
• Check for signs of rot, splitting, or insect activity

Addressing minor issues now can prevent more significant, costly problems later.

Issaquah Lumber Has You Covered

We offer a variety of prep and finish products tailored to your wood type and project goals—from traditional stains, oils, or even paint, we can help you find the right solution and guide you through the process.

If you’re not sure what your deck needs, bring us a photo or give us a call. A little prep now means a longer-lasting, better-looking deck all year long.