Safe Roof Cleaning: Top Myths Debunked (Part Three)

Top Myths About Power Washing Debunked (Part Three)

Continuing from Top Myths About Power Washing Debunked (Part Two), this section looks at Myths 8 and 9. These two myths show where power washing is often pushed beyond its limits and where a different approach is safer for your property.

Myth 8: Power Washing Is Perfect For Roof Cleaning

Fact: Roofs Need Specialized Soft Washing, Not High Pressure

Power washing is great for many exterior surfaces, but your roof is not one of them. High-pressure water on roofing can cause more harm than good.

Why high pressure is a problem on roofs:

Asphalt shingles: The force of the water can strip away the protective granules on shingles. Once these granules are gone, shingles age faster and become more vulnerable to leaks and UV damage.
Tile roofs (clay, concrete, slate): Strong pressure can crack or dislodge tiles, creating gaps where water can get in and cause interior damage.
Metal roofs: Even durable metal roofs can be compromised if high-pressure water forces moisture under seams or damages protective coatings.

Most roofing manufacturers specifically warn against high-pressure cleaning and may void a warranty if it is used.

Soft Washing: The Right Way To Clean A Roof

Instead of power washing, soft washing is the preferred method for roof care.

Soft washing uses:

Low pressure: Gentle water flow that will not strip or loosen roofing materials
Special roof-safe cleaners: These break down organic growth like moss, algae, lichen, and mildew

This approach:

Removes black streaks, green patches, and staining
Kills algae and moss at the root to slow regrowth
Protects shingles, tiles, and metal coatings from pressure damage

Why Roof Growth Needs Attention

Moss: Can lift shingles and trap moisture, leading to rot and water intrusion.
Algae: Causes staining and contributes to shingle deterioration over time.
Trapped moisture: Increases the risk of wood rot, attic mold, and issues like ice dams in colder months.

Regular soft washing helps:

Keep the roof cleaner for longer
Reduce moisture problems
Support the long-term life of the roofing system

Choosing soft washing over power washing is not just safer. It also respects manufacturer guidelines and helps protect both your roof and your warranty.

Myth 9: Power Washing Solves Long-Term Property Issues

Fact: It Is Only One Part Of A Larger Maintenance Plan

Power washing is excellent for removing surface dirt, algae, mildew, and stains. It improves curb appeal quickly. But it does not repair deeper issues or replace ongoing maintenance.

What Power Washing Can Do

Clean decks, driveways, siding, patios, and walkways
Remove surface mold, algae, and built-up grime
Prepare surfaces for sealing, staining, or painting

What It Cannot Do

Fix damaged wood: Power washing can make a deck look better, but it will not repair rot, structural weakness, or warped boards.
Repair concrete or stone: It will not fill cracks or correct settlement issues. Sealing and repair work are still needed to protect the surface.
Solve roofing problems: Even when cleaned correctly, only inspections, repairs, and proper ventilation can address leaks, worn shingles, or flashing problems.
Restore failing gutters: Cleaning out debris is important, but bent, loose, or poorly pitched gutters still need repair or replacement.

Why Power Washing Should Be Paired With Other Maintenance

For long-term results, power washing should be followed or supported by:

Sealing and coating:
- Sealing concrete and pavers after cleaning helps protect against future stains and moisture.
- Staining or sealing decks after washing helps defend against UV and water damage.
Repairs:
- Replace rotten deck boards or failing fence panels rather than just washing them.
- Patch or resurface cracked concrete where needed.
Moisture control:
- Fix drainage problems that feed recurring mold and mildew.
- Address leaky gutters and downspout issues that cause water to pool near foundations.