Not all roof cleaning methods are equal. Using the wrong one can strip the granules protecting your shingles, void your manufacturer warranty, and put your insurance coverage at risk, without you ever knowing until it's too late. Heritage uses ARMA-approved soft washing on every roof job. Here's what that means and why it protects your home.
ARMA, the Asphalt Roofing Manufacturers Association, is the trade organization that represents the manufacturers behind the most widely installed roofing products in North America. GAF, Owens Corning, CertainTeed, IKO, Atlas, these companies and others operate under ARMA's technical guidelines for how asphalt shingle roofs should be installed, maintained, and cleaned.
ARMA's guidance is not a suggestion. When a manufacturer's warranty says "improper cleaning methods void this warranty," the definition of "improper" traces directly back to ARMA's published standards. If your roof was cleaned using a method ARMA does not approve, and something goes wrong, your warranty claim can be denied. Your insurance adjuster can use the same documentation to reduce or deny a related claim.
This standard isn't widely known, and that's exactly why Heritage built its roof cleaning program around it. Understanding what ARMA recommends, and why the manufacturers behind your shingles put it in writing, gives you the information to protect your investment and make confident decisions about your property.
Understanding what high-pressure cleaning does to asphalt shingles helps you protect your home for the long term.
Asphalt shingles are coated in mineral granules, the rough texture you see and feel on a new roof. Those granules are the UV protection layer. They determine how long the shingle lasts. High-pressure water physically dislodges granules, especially on shingles that have already weathered a few years. You lose 5–10 years of roof life every time a pressure washer runs across it.
Major shingle manufacturers including GAF, Owens Corning, and CertainTeed include language in their warranties specifying that improper cleaning methods void coverage. ARMA defines pressure washing as an improper method for asphalt shingles. If you file a warranty claim after a pressure wash, the manufacturer can, and does, deny it by pointing to the cleaning history. Your roof is under warranty on paper, but not in practice.
Homeowner's insurance policies carry "improper maintenance" exclusions. If a roof is damaged and an adjuster determines it was cleaned using a method the manufacturer explicitly warns against, the claim can be reduced or denied. This is not a common scenario, until it happens to you. A $400 pressure washing job that voids the warranty and triggers a denied insurance claim is not a savings. It's a liability.
Pressure washing is not the only cleaning method that affects your warranty. Roof brushing, using stiff brushes or brooms to physically scrub algae and moss off shingles, dislodges granules just as effectively as high-pressure water. The scrubbing action lifts and removes the protective granule layer, shortening the life of the shingle and triggering the same warranty exclusions. ARMA does not approve brushing for the same reason it does not approve pressure washing: any method that physically abrades the shingle surface causes granule loss. The only approved method is low-pressure soft washing, where chemistry does the cleaning and no mechanical force contacts the shingle.
Soft washing requires different equipment, professional-grade chemistry, and more care than other methods. Heritage invested in the right setup because your roof represents one of the largest investments in your home, and the method used to clean it has real consequences for how long it lasts, whether your warranty holds, and whether your insurance coverage stays intact. We'd rather you understand exactly what's being done to your property and why.
ARMA's technical guidance is explicit: asphalt shingle roofs should be cleaned using a low-pressure wash, delivered well below the threshold that dislodges granules, combined with a cleaning solution formulated to kill biological growth at the root. The guidance specifically identifies algae (including Gloeocapsa Magma, the organism responsible for the dark streaks common across North Idaho roofs), moss, lichen, and mildew as the biological growth types soft washing addresses.
The key principle is chemistry over force. The dark staining on a roof is not dirt, it's a living organism embedded in the shingle surface. Blasting it off with pressure removes the visible growth but leaves the root structure intact, and it regrows within months. A properly formulated soft washing solution kills the growth at the root, which is why soft washed roofs stay cleaner for 12–24 months versus pressure washed roofs that show regrowth in a single season.
This is also why the method matters more than the price. Two roof cleaning quotes are not the same service if they use different methods. One shortens your roof's life. The other protects it.
| Pressure Washing | Soft Washing (ARMA-Approved) | |
|---|---|---|
| ARMA-Approved for Asphalt Shingles | No, explicitly not approved | Yes, the only approved method |
| Manufacturer Warranty Impact | Voids warranty on most major brands | Warranty remains intact |
| Insurance Policy Risk | Potential claim denial for improper maintenance | Compliant with standard maintenance requirements |
| Granule Loss | Significant, reduces roof lifespan | None, low pressure protects granules |
| Kills Growth at the Root | No, blasts surface, regrowth in months | Yes, chemistry kills root structure |
| Results Last | 3–6 months before regrowth | 12–24 months |
| Safe on Painted Siding & Wood | Risk of paint damage and wood fiber damage | Safe on all exterior surfaces |
Note: Roof brushing carries the same warranty implications as pressure washing. Any method that physically abrades the shingle surface, including stiff brush scrubbing, causes granule loss and is not approved by ARMA. The comparison above applies to brushing as well.
Every roof Heritage touches follows the same ARMA-compliant process from start to finish.
Heritage evaluates the roof type, age, shingle condition, and growth type before any work begins. We identify whether moss, algae, lichen, or a combination is present, different growth types respond differently to treatment. We provide a written estimate based on what we actually see.
We apply a professional-grade soft washing solution at low pressure, well within ARMA's approved range. The chemistry is matched to the growth type and surface. Landscaping and surrounding areas are pre-wetted and protected before application begins.
After the solution has had time to work, we rinse the surface thoroughly. Before-and-after photos are taken on every job. We review any concerns about the roof condition with you directly and discuss maintenance scheduling to keep the roof protected going forward.
A roof is one of the most expensive components of a home to replace. Heritage built its cleaning program around ARMA's guidelines because your shingle warranty, your insurance coverage, and the long-term condition of your roof all depend on how it's maintained, not just whether it looks clean the day after the job is done. We want every homeowner we work with to feel confident that what we did to their property protected it.
Following ARMA standards also produces better results. A roof soft washed the right way looks cleaner longer, keeps biological growth from returning as quickly, and doesn't lose the granule layer that determines how many years the shingles have left. It's the method that actually serves your home, and that's the only kind of work Heritage is interested in doing.
Low-pressure soft washing is Heritage's standard for every asphalt shingle roof. No exceptions, no upsell required.
Licensed, registered, and operating to Idaho's contractor standards. Accountability starts with proper credentials.
Heritage carries full general liability insurance. Anyone on your roof or working the exterior of your property is covered.
We document every roof job with before-and-after photos. You have a record of the work, the condition of the roof, and what was done, useful if a warranty or insurance question ever comes up.
Yes, for most major shingle manufacturers, it can. GAF, Owens Corning, CertainTeed, and others include language in their warranties specifying that improper cleaning methods void coverage. ARMA identifies pressure washing as an improper method for asphalt shingles due to granule loss. Roof brushing carries the same risk: physically scrubbing shingles with stiff brushes dislodges granules the same way high-pressure water does, and ARMA does not approve it for the same reason. If you file a warranty claim after a roof has been pressure washed or brushed, the manufacturer can deny the claim based on your maintenance history. The warranty exists on paper, but the manufacturer has a documented reason not to honor it.
ARMA recommends low-pressure washing combined with a cleaning solution formulated to kill biological growth. The low-pressure delivery protects shingle granules, and the solution kills algae, moss, and mildew at the root rather than blasting it off the surface. This is exactly the method Heritage uses. ARMA does not approve high-pressure washing for asphalt shingle roofs, the pressure strips the mineral granule layer that protects the shingle from UV and weather damage.
The dark streaking common on North Idaho roofs is caused by a cyanobacteria called Gloeocapsa Magma, a blue-green algae that feeds on the limestone filler in asphalt shingles. It spreads by spore across rooftops and thrives in humid, shaded environments. The dark color comes from the protective sheath the organism develops to block UV. It's not cosmetic only, Gloeocapsa Magma damages shingles over time. Soft washing kills it at the root with the appropriate chemistry; pressure washing blasts it off the surface temporarily while the root structure regrows within months.
The most visible sign is excessive granule loss, bare spots or areas where the shingle looks smooth or worn through, often visible in gutters as a buildup of dark granules. A Heritage technician can assess the roof condition during the on-site estimate and give you an honest picture of where the shingles stand. If you have documentation of past cleaning work, checking that against the method used is worth doing before the next warranty-related issue comes up.
For most North Idaho homes, every 12–24 months is appropriate depending on the roof's environment, tree coverage, shade patterns, and proximity to moisture all affect how quickly biological growth returns. Roofs with heavy tree canopy overhead tend to need annual attention; more exposed roofs can go two years between treatments. Heritage's Residential Annual Program includes roof soft washing as part of a scheduled spring or fall visit so the timing is managed for you.
When performed correctly, soft washing does not damage shingles, it's the ARMA-approved method specifically because it does not. Landscaping is protected by pre-wetting plants and surrounding vegetation before solution application and rinsing after. Heritage takes standard precautions on every job. The cleaning solution breaks down after rinsing and does not persist in soil at concentrations harmful to established plants. Pets should be kept away from the work area during application and rinsing; once dry and rinsed, the area is safe.
Heritage provides written estimates, follows ARMA-approved soft washing on every roof job, and documents the work with before-and-after photos. No shortcuts.