Roof soft washing starts at $600, with most jobs priced at $0.35-$0.45 per square foot of roof surface. The final number depends on roof size, pitch, and how severe the algae staining is, not a flat per-house rate. Here’s what actually moves that number, and why it’s worth it compared to the alternative.

Our pricing structure

We start every roof job at $600, with pricing scaling from there at $0.35-$0.45 per square foot of roof surface based on size, pitch, and staining severity. A smaller single-story roof with light staining lands at or near the $600 minimum. A larger two-story roof, a steep pitch, or heavy multi-year algae buildup pushes toward the higher end of the per-square-foot range.

What drives the price within that range

• Roof size (square footage). Priced per square foot of roof surface, so a 2,500 sq ft single-story home costs less to treat than a 4,000+ sq ft two-story.
• Pitch and accessibility. A steep pitch or a roof with multiple gables and dormers takes longer to work safely and thoroughly than a simple low-slope roof.
• Staining severity. A roof with light streaking needs one clean application. A roof that’s gone untouched for 5+ years with heavy black algae buildup may need a stronger application or a second pass, which adds cost.
• Story count. Two-story and three-story homes require more setup (ladders, hose runs, safety precautions) than single-story homes.
• Moss or lichen presence. Less common in this area than pure algae staining, but when present it can require additional treatment time.

Why we quote per square foot instead of a flat price

Any roof-cleaning quote given over the phone without seeing the roof is a guess, not a real price. We give exact quotes after a look at the roof (in person or from photos) using our $600 starting point plus $0.35-$0.45 per square foot, because a 1,800 sq ft single-story roof and a 4,200 sq ft two-story with heavy staining are genuinely different jobs that shouldn’t cost the same.

Is it worth the cost compared to doing nothing, or replacing the roof?

A soft wash costs a small fraction of what a full roof replacement runs (commonly $8,000-$20,000+ in the Houston area), and it’s the manufacturer-recommended way to remove algae staining without the granule loss or warranty risk that comes from pressure washing. See our roof cleaning vs roof replacement guide if you’re not sure which situation you’re actually in.

If you’re comparing quotes, our guide to choosing a roof soft-washing company covers the questions that separate a real quote from a lowball that cuts corners.

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Related

• Roof Cleaning vs Roof Replacement
• How to Choose a Roof Soft-Washing Company
• House Pressure Washing Cost Guide