Should You Pressure Wash a Wood Roof?

If you own a wood shake or shingle roof in Colorado or Georgia, chances are you've wondered whether pressure washing is safe or effective. The short answer? It’s usually a bad idea. Pressure washing might seem like a quick fix, but it can actually shorten the lifespan of your roof and cause irreversible damage.

Here’s what you need to know before reaching for the power washer.

Why Pressure Washing Wood Roofs Is Risky

Wood shake and shingle roofs are made to breathe and naturally shed water. High-pressure washing interferes with both functions.

The major risks include:

• Damaging the wood fibers. Pressure washers can strip away the soft outer layer of cedar, which weakens the shakes and speeds up deterioration.

• Forcing water into the roof system. High-pressure water can get under shingles and into your underlayment, leading to hidden moisture damage, mold, and rot.

• Voiding your warranty. Many cedar roof manufacturers and the Cedar Shake & Shingle Bureau warn that pressure washing may void installation or material warranties.

What the Experts Recommend Instead

According to the Cedar Shake & Shingle Bureau and top roofing contractors, here’s how to safely maintain a wood roof:

1. Use Gentle Cleaning Techniques

• Apply a wood-safe cleaner using a soft brush or low-pressure sprayer (under 400 psi).

• Avoid bleach or harsh chemicals that can dry out the wood.

• Rinse thoroughly with a garden hose—not a pressure washer.

2. Schedule Routine Inspections

• Have a certified roofer inspect your wood roof every 2–3 years.

• Look for split, curled, or missing shakes; buildup of moss or debris; and signs of insect activity.

3. Keep It Dry & Debris-Free

• Trim overhanging branches.

• Keep the roof and valleys clear of pine needles and leaves.

• Make sure gutters and downspouts are flowing properly.

What About Moss and Algae?

Moss and algae don’t just look bad—they trap moisture. But blasting them off with a pressure washer usually does more harm than good.

Instead, try:

• A gentle brushing and non-toxic moss treatment.

• Hiring a roofing contractor familiar with wood roof preservation methods.

Should You Ever Pressure Wash a Wood Roof?

In rare cases—like prepping for wood treatment—an ultra-low pressure rinse (under 100 psi) might be done, but only by a qualified wood roofing expert. Even then, dry conditions and follow-up maintenance are critical.

FAQs

Can I pressure wash a cedar shake roof?

No. Pressure washing damages the wood, forces water underneath shingles, and can void warranties. Use soft wash methods instead.

How do I clean moss off a wood roof?

Use a non-toxic moss treatment and a soft-bristle brush. Avoid bleach, wire brushes, or pressure washers.

Is mold on a wood roof dangerous?

Yes. Mold and mildew retain moisture and accelerate decay. Proper roof ventilation and safe cleaning are key to prevention.

Need Wood Roof Help in Colorado or Georgia?

Whether you’re in Denver, Colorado Springs, Atlanta, or Savannah, Roof Nuts offers expert inspections, soft cleaning, and repairs for wood shake and shingle roofs. Call us today:

• Colorado: 303-276-2403

• Georgia: 404-476-6851

• Schedule Service: https://roofnutsco.com | https://roofnutsga.com

Protect your investment. Skip the pressure washer—and trust the wood roofing pros.