Cedar siding is one of the most beautiful exteriors a home can have -- and one of the most expensive to repair when cleaned the wrong way. Use too much pressure and you can split fibers, strip the finish, or force water into the wall cavity. Cedar siding repair runs $4 to $13 per square foot, so a single botched job can cost a homeowner thousands. Here's exactly how to pressure wash cedar siding without causing damage.

The Quick Answer

Cedar is a softwood. It needs low pressure and careful technique:

Max PSI: 1,200-1,500 (stay closer to 1,200 when in doubt)
Nozzle: 25-40 degree tip only -- never use a 0 or 15 degree tip
Distance: Start 4-6 feet away from the surface
Direction: Always spray with the grain, never against it
Cleaner: Mild detergent or oxygen bleach -- no undiluted chlorine bleach
Contractor rate: $0.25-$0.40 per sq ft for cedar siding cleaning

The most common mistake is using the same PSI and technique that works on concrete. Cedar is nowhere near as forgiving. Take a soft approach and you'll restore the wood. Rush it and you'll pay for it.

Why Cedar Needs a Different Approach

Cedar is a softwood, which means its wood fibers are loosely packed compared to hardwoods. High-pressure water can tear those fibers apart, leaving the surface looking fuzzy or splintered. It can also strip the protective stain or sealant that keeps moisture out.

The real danger is water infiltration. If you spray upward under the lap boards, or hit the wood straight-on with too much force, you can drive water behind the siding. That water has nowhere to drain, which leads to rot and mold inside the wall cavity -- the kind of damage that costs $1,000-$5,000 to fix properly.

How to Pressure Wash Cedar Siding: Step by Step

Step 1: Pre-Wet the Surface

Before applying any detergent, wet the cedar siding with a low-pressure rinse using a garden hose or the widest nozzle on your pressure washer. This prevents detergent from drying on the surface and helps loosen surface dirt before you start cleaning.

Step 2: Apply a Cedar-Safe Detergent

Use a mild detergent or an oxygen bleach solution mixed with water. Apply it with low pressure or a soft brush. Let it dwell for 5-10 minutes -- long enough to break down mildew and grime, but not so long that it dries on the surface.

Avoid undiluted chlorine bleach. It's too harsh for cedar and will lighten the wood unevenly, leaving blotchy patches that are difficult to correct.

Step 3: Pressure Wash with the Right Settings

Set your machine to 1,200-1,500 PSI. Attach a 25 or 40 degree nozzle. Start 4-6 feet away and move in only if you need to -- never get closer than 12-18 inches from the surface.

Spray with the grain and follow the direction of the lap. For horizontal clapboard siding, sweep left to right or right to left. Never spray upward into the gap between boards. That's how water gets behind the siding.

Step 4: Keep the Wand Moving

Don't stop the wand mid-stroke. Keeping it moving prevents concentrated pressure from dwelling on one spot. Use smooth, overlapping passes that cover each section fully before moving to the next.

Step 5: Rinse Top to Bottom

Rinse the siding from the top down so dirty water runs off the house rather than onto sections you've already cleaned. Keep pressure low during the rinse -- you're just washing off detergent residue, not blasting away grime.

Test a Small Area First

Always test an inconspicuous section before tackling the whole house. Spray a 2x2 foot patch and check after a few passes. If you see fibers lifting or the surface turning fuzzy, back off the pressure or increase your distance. Better to find out on a hidden corner than on the front of the house.

This step also matters for contractors documenting pre-existing damage. Take photos before you start so you're not blamed for conditions that were already there.

What Happens If You Get It Wrong

The most common damage from over-aggressive pressure washing on cedar:

Fuzzing or splintering: Visible surface fiber damage. Looks rough and traps more dirt going forward.
Stripped finish: If the cedar was stained or sealed, high pressure removes the protective coating and leaves the wood exposed.
Water infiltration: Wrong spray angle forces water behind boards, leading to mold and rot inside the wall cavity.
Repair cost: Cedar siding repair runs $4-$13 per square foot. Replacing a damaged section including labor can easily run $500-$2,000.

Pricing for Contractors

Cedar siding cleaning commands a premium over standard vinyl or aluminum jobs because of the extra care required. If you're quoting cedar, price accordingly:

Cedar siding cleaning: $0.25-$0.40 per sq ft
Cedar restoration and staining (upsell): $1.50-$3.00 per sq ft
Minimum charge: $200-$350 for cedar siding jobs
Mildew treatment add-on: $50-$150 depending on coverage area

Cedar jobs are a strong upsell opportunity. After cleaning, you can offer restoration and staining as a separate service. The homeowner just paid for cleaning -- the wood is clean and you can see its exact condition. Offering to restore the finish and protect the wood is a natural next step that adds $500-$1,500 or more to the average job.

Bottom Line

Pressure washing cedar siding is not complicated, but it is easy to mess up if you use the same aggressive settings you'd use on concrete. Keep PSI under 1,500, use a wide nozzle, spray with the grain, and never shoot upward into the board gaps. Do it right and you'll restore the cedar's natural look and earn a customer for life.

If you're quoting cedar siding jobs and want to give customers an instant price estimate on your website, try QuoteSnap for free. Set your rates, embed the calculator, and let homeowners get a price in 30 seconds -- no phone tag required.

Pressure Washing Cedar Siding: How to Restore It Without Damage (2026)