Does Roof Cleaning Void Your Warranty?
If you’ve noticed dark streaks, green patches, or fuzzy moss creeping across your roof, you’re not alone, and you’re probably wondering whether cleaning it is safe, or whether the wrong method might do more harm than good.
The short answer: the right cleaning method not only won’t void your warranty, it’s actually required by most manufacturers to keep your roof performing as intended. The wrong method, however, can absolutely void coverage and cause real damage.
Here’s what the manufacturers themselves say.
Why Your Roof Gets Dirty and Why It Matters
That dark staining you see on asphalt shingles isn’t dirt. It’s a blue-green algae called Gloeocapsa magma, and it feeds on the limestone filler in your shingles. Left unchecked, it holds moisture against the roof surface, accelerates shingle granule loss, and shortens the life of your roof significantly.
Moss and lichen do even more damage, their root-like structures physically lift shingle edges, allowing water to penetrate underneath.
The good news is that every major shingle manufacturer acknowledges this problem and has a published, approved cleaning solution.
What the Manufacturers Actually Recommend
GAF — The Industry Standard
“GAF recommends cleaning the roof with a special mixture. That mixture is: 4 gallons of water, 1 gallon of bleach and 1 cup of TSP… Apply this mixture with a garden sprayer, let sit for up to 20 minutes, and rinse with low-pressure water.”
They also explicitly state: “Do not power wash the shingles… it may dislodge granules, which can lead to premature shingle failure.”
ARMA — The Industry Trade Body
The Asphalt Roofing Manufacturers Association (ARMA) sets the standards that all major shingle manufacturers follow. Their technical bulletin on algae discoloration (revised June 2024) states:
“Discoloration may be lightened by applying a solution of liquid household bleach (sodium hypochlorite) and water… left on the roof for at least 15 minutes but no more than 20 minutes… rinse the solution from the roof by gently spraying the surface with water. DO NOT use a power washer.”
This is the governing standard. Any contractor who pressure washes your asphalt shingle roof is working against manufacturer specifications — not with them.
Owens Corning & CertainTeed
Both Owens Corning and CertainTeed publish near-identical maintenance guidance:
“Mix a solution of 1 part chlorine bleach with 3 parts of water. Apply this solution using a low-pressure hand-held sprayer over the asphalt shingles… After 15 minutes, rinse the bleach solution from the roof.”
The message is consistent across every major manufacturer: soft-wash sodium hypochlorite, low pressure, thorough rinse.
IKO
How Servus Cleaning Meets Manufacturer Specifications
Here’s how our method stacks up against manufacturer specs:
| Specification | What Manufacturers Say | Servus Cleaning Method |
| Cleaning agent | Sodium hypochlorite (bleach) | ✅ 4% NaOCl solution |
| Application pressure | Low pressure/garden sprayer | ✅ Low or no pressure |
| RinsingGentle | low-pressure rinse | ✅ Thorough rinse after treatment |
| Power washing | ❌ Universally prohibited | ✅ Never used on shingles |
Which Roof Types Can Be Cleaned with Sodium Hypochlorite?
✅ Safe to Clean with SH (Bleach Solution)
Asphalt Shingles (GAF, Owens Corning, CertainTeed, IKO, Malarkey)
Painted / PVDF-Coated Metal Roofing
Concrete and Clay Tile
❌ Do NOT Use Bleach On These Roofs
Galvalume Metal Roofing
⚠️ Proceed with Caution
Stone-Coated Steel (DECRA, Gerard)
GAF EverGuard TPO / Duro-Last PVC (Flat Roofing)
Cedar & Wood Shake
