It can, if the roof is cleaned the wrong way, and the terms vary by manufacturer. That is the measured answer, and it is the one we give to homeowners in Howell and across Livingston County.
A customer once called us about black streaks and asked one thing first: “Will this hurt my warranty?” It is a smart question, and the answer is to check before you book. This post covers what shingle makers and the Asphalt Roofing Manufacturers Association (ARMA) say, why soft washing is the accepted method, and what to check first. We are not roofers, and we cannot tell anyone what their own warranty says.
Can Roof Cleaning Void My Shingle Warranty? The Short Answer
It can, depending on how the roof is cleaned and what your shingle warranty says. High pressure washing can strip protective granules, and shingle makers and ARMA advise against it. Low pressure soft washing is the accepted method, but read your own warranty and ask the manufacturer before booking.
Not sure your roof is ready for cleaning? Start with your warranty, then get a free estimate and we will talk through the method.
How Do Shingle Warranties Work?
Most roofs have more than one kind of coverage. It helps to know which one you are looking at.
What Does a Manufacturer Warranty Cover?
A manufacturer warranty generally covers material defects for a set period, and it usually comes with conditions. The major makers include GAF, Owens Corning and CertainTeed. Their terms differ by product line, so we do not state coverage years or terms for any brand. Your own document is the only one that counts for your roof.
What Is a Workmanship Warranty?
This covers the installation, and it comes from the roofer, not the shingle maker. If something was installed poorly, this is the document to look at. It is separate from the manufacturer warranty, and it has its own terms.
What Is an Algae Resistance Warranty?
Some shingle lines include algae resistant granules, and some come with a separate algae coverage that has its own terms. Owens Corning, for example, has a page on dark streaks on roofs that explains algae and algae resistant shingles. Treat that as an example, not a rule. Terms vary by maker and by product line.
What Conditions Can Affect Any Warranty?
Warranties may require proper installation, ventilation and reasonable maintenance. Using methods the maker does not approve can be a problem too. Read the document, and look for the sections on maintenance and cleaning.
What Do Shingle Makers and ARMA Say About Cleaning?
This is the part we most want you to read. We stay with what we could verify.
What Does ARMA Say?
ARMA’s algae discoloration page is direct. It says not to use a power washer, or any brush or broom, to clean algae from the roof surface. It describes a gentle bleach and water solution, left on for at least 15 minutes but no more than 20, and then rinsed off with a gentle spray of water. It says the effect is only temporary, and the discoloration may come back.
ARMA also says to avoid scrubbing, because the friction may loosen and remove granules. It warns that the roof may become slippery and hazardous. And it says other cleaning chemicals or methods should not be used without the approval of the shingle manufacturer. When reroofing, algae resistant shingles are an option.
What Does an ARMA Technical Bulletin Add?
A bulletin from ARMA, hosted by CASMA, adds more detail. It says the brown to black staining on light shingles comes from a common airborne algae called Gloeocapsa. It says the staining is not indicative of a shingle defect, and that it has not been shown to shorten service life. It warns that pressure washing can damage shingles by loosening and removing the mineral granules. And it says zinc or copper strips near the ridge, or treated granules, can slow algae growth.
What Does Owens Corning Say?
Owens Corning’s guidance on dark streak stains says the main culprit is Gloeocapsa magma, a cyanobacterium that spreads through the air. It says the company has seen no evidence that algae affects shingle performance, and calls it more of an aesthetic problem.
It says to avoid scrubbing and high pressure power washing. It says stains may be lightened with a bleach and water mix, and that the result is typically temporary. It recommends consulting a licensed roofing professional first, and it notes that wet roofs are slippery. Algae resistant shingles use copper lined granules.
What About GAF and CertainTeed?
GAF and CertainTeed are two more major makers, and their warranty terms differ. We do not quote their cleaning rules here. Find each company’s current roof care page and your warranty document, and read what applies to your product line.
Why Can High Pressure Damage or Void Shingle Coverage?
Shingles are protected by mineral granules, and force can knock them off. That is the heart of the issue.
What Do Granules Do?
They shield the asphalt from UV and sun. The ARMA bulletin says granules protect the asphalt from UV exposure, so they should stay in place. A roof with fewer granules has less protection from the sun.
How Does High Pressure Harm a Roof?
High pressure can cause granule loss. It can lift edges, and it can force water under shingles. It may also loosen flashing. The damage may not be visible from the ground, so a roof can look fine and still be harmed. A neighbor who rents a machine and notices granules in the gutter later is a common story. That is a general scenario, not a specific incident.
Does That Mean Cleaning Always Voids a Warranty?
No, and we do not want to scare anyone. A warranty may be affected if a roof is damaged by a method the maker does not approve. Whether a claim is accepted depends on the document and the maker. We cannot claim a rule that is not in your paperwork.
Why Is Soft Washing the Accepted Method for Roofs?
Soft washing is accepted because it cleans with low pressure and a cleaning solution instead of force. See our roof cleaning in Livingston County page for how we approach it.
What Is a Soft Wash Roof Clean?
It uses low pressure water and a cleaning solution that kills algae, left to dwell and then rinsed gently. Our soft wash systems use low pressure and professional detergents. Makers and ARMA describe a gentle bleach and water approach, and cleaning solutions differ from one company to the next. Ask any cleaner what they use, and ask your shingle maker what it approves.
Why Is It Gentler on Shingles?
The chemistry does the work. No scrubbing or high pressure is needed, so the granules stay on the roof.
Does Soft Washing Guarantee Warranty Protection?
No. No cleaning method can guarantee how a manufacturer will treat a claim, because that depends on the maker’s terms. Soft washing is simply the method that matches what makers and ARMA describe. Our 100% satisfaction guarantee is about our work. It is not a shingle warranty, and we do not offer one.
Is Soft Washing Permanent?
No. Algae can return, and ARMA says the effect can be temporary. Shaded roofs return faster. If you want to know why growth comes back, read why roof mold returns.
What Causes Black Streaks on Roofs in Michigan?
The dark streaks are usually algae called Gloeocapsa magma. Here is what to know.
What Is Gloeocapsa Magma?
It is a common airborne algae, a cyanobacterium, according to Owens Corning. It spreads through the air, so it can land on any roof.
Why Do Some Roofs Stain Faster Than Others?
Shade, trees, moisture and north facing slopes all matter. Michigan humidity and wooded Livingston County lots add to it. We have seen a shaded north slope under mature trees show streaks first. Green algae and moss tend to show up on roofs that are shadier and damper.
Is Roof Algae a Defect?
The ARMA bulletin says the staining is not indicative of a shingle defect. Algae resistance coverage is a separate item, with its own terms. Check your document to see what applies.
How Can You Help Prevent It?
At reroofing, algae resistant shingles are an option. Zinc or copper strips near the ridge can also slow growth. ARMA’s bulletin suggests strips for new or reroofed buildings. Strips involve working on the shingles, so ask your maker or roofer how and whether to install them on your roof.
What Should You Check Before You Book Roof Cleaning?
This is the most useful part of the post. Here is what to do.
What Should You Read in Your Own Warranty?
- Find the document. Look in your closing papers, your roofer’s invoice, or your manufacturer’s website account.
- Look for sections on maintenance, cleaning and unapproved methods.
- Note the shingle line, installation date and registration steps.
- Note whether the warranty has been transferred or registered.
Who Should You Call?
Call the shingle manufacturer and your roofer. One customer could not find their paperwork at first, and learned the roofer had a copy. Here is a short script: “I want to clean algae off my roof with a low pressure soft wash. What methods and cleaning solutions do you approve?”
How Do You Get It in Writing?
Ask for an email or a letter, and keep a copy with your roof papers. One customer emailed the shingle maker before booking, and shared the reply with us. Ask the cleaning company for a written description of the method, the cleaning solution and the pressure. Ask for a certificate of insurance too. Keep before and after photos.
What If the Roof Is Steep or Old?
Steep, multi story and older roofs add risk. Some jobs are better inspected first by a roofer. Safety comes first, and we never suggest unsafe practices. If you are unsure, ask us, and we will talk it through.
Send your questions through the quote form on our contact page. We will explain our process so you can share it with your roofer or the shingle maker. New customers get a discount with First Time Offer.
How Can You Spot a Risky Roof Cleaner?
A good roof cleaner can explain the method, put it in writing and answer your roofer’s questions. A risky one cannot.
What Are the Red Flags?
- Uses a pressure washer on shingles
- Scrubs or brushes the roof
- Promises you will keep your warranty, or that nothing can go wrong
- Cannot say what cleaning solution is used
- No insurance proof
- Will not put the method in writing
- Offers a lifetime result
What Good Answers Sound Like
Look for low pressure, a named method, a written estimate, and a willingness to talk to your roofer. For more, read how to choose the right pressure washing service for your home.
Can You Clean Your Own Roof?
It is possible, but it is risky. The first risk is a fall. Wet shingles are slippery, and ARMA says the cleaning process can make a roof hazardous. The second risk is granule loss from scrubbing. The third is bleach runoff onto plants and foundation beds. And there is the possibility of warranty issues, if you use a method the maker does not approve.
We do not give steps for walking on a roof, because we do not want anyone to get hurt. If you want a closer look at cleaning algae, read our post on how to remove algae and mildew from your roof safely. You can also read about pressure washer rental vs hiring a pro.
What Happens on the Day of a Roof Cleaning With LPW?
Here is the order we follow.
Before We Arrive
We ask you to give us clear access to your water spigots and outlets. We also ask you to move cars and patio items away from the work area. Keep pets inside.
During the Wash
We protect plants and foundation beds. We apply the cleaning solution with low pressure, let it dwell, and rinse gently. We do not scrub the roof.
After the Wash
Streaks fade as the roof dries, and rain helps. Results vary with how deep the staining goes. We check the gutters and downspouts afterward, and you can also read about our gutter cleaning service. Keep your invoice and photos for your records.
Practical Examples: Three Roof Situations
A Shaded North Slope With Streaks
A homeowner checks the warranty first, then books a soft wash. That order is the one we like to see.
A Roof Under Warranty With an Unclear Document
The homeowner emails the maker, asks what is approved, and keeps the reply. The reply goes in the roof folder, next to the invoice.
A Neighbor Who Rented a Pressure Washer
A neighbor rents a machine, runs it over the shingles, and later finds granules in the gutter. That is what can go wrong, and it is why we do not recommend it.
Frequently Asked Questions About Roof Cleaning and Shingle Warranties
Does pressure washing a roof void the warranty?
It can. Shingle makers and ARMA advise against power washing roofs, because it can loosen granules. Read your own warranty, and ask the manufacturer before anyone cleans your roof.
Is soft washing safe for asphalt shingles?
It matches the low pressure approach that makers and ARMA describe. No method can guarantee warranty outcomes, so check your own warranty and ask your maker first.
Does roof algae void a warranty?
ARMA’s bulletin says algae staining is not indicative of a shingle defect. Algae resistance coverage is separate, so check your own warranty.
Who should I call about my warranty?
Call the shingle manufacturer and the roofer who installed the roof. Between them, they can tell you what your coverage says.
Should I get cleaning approval in writing?
Yes. Ask for an email or a letter, and keep a copy with your roof papers. It is a simple record if questions come up later.
Do zinc or copper strips work?
ARMA’s bulletin says a strip near the ridge can slow algae growth on new or reroofed buildings. Ask your roofer whether it makes sense for your roof.
How often should a roof be cleaned?
It depends on shade and moisture. We do not give a schedule. A shaded roof under mature trees will usually need attention sooner than a sunny one.
Can I clean a roof in winter?
Our terms allow us to reschedule for freezing temperatures, so we do not plan roof cleaning in freezing weather. Ask us when you call.
What is Gloeocapsa magma?
It is a common airborne algae that causes black streaks on roofs, according to Owens Corning. It is a cyanobacterium.
Get a Free Roof Cleaning Estimate in Livingston County
Warranty terms vary by maker and product line, so check your own document first. We will not promise a warranty result, and no honest company can.
Call Livingston Pressure Washing at 810 360 1002 or use the quote form on our contact page for a free roof cleaning estimate in Howell and Livingston County. New customers get a discount by mentioning First Time Offer. See all the areas we serve.
