How to Clean Asphalt Roof

How to Clean an Asphalt Roof Safely & Effectively
a Step-by-Step Guide

Welcome to Wash Safe™ Industries. In this step-by-step guide, we're going to teach you how to clean asphalt roof shingles safely and effectively using our original eco-safe Roof Wash and cleaning method. With 13+ years of experience cleaning over 2,500 roofs, we've engineered both technique and formulations to rid properties of pesky, ugly stains from moss, mold, lichen and algae while preventing them from coming back without bleach or harmful chemicals. You can also download and print by clicking the quick link below.

Frequently asked questions and answers are also provided to help guide you along the roof cleaning process.


How can I tell if there is moss, mold, algae or lichen growing on my roof?

Look like this? It's probably this:
how to clean moss off your roof

Roof Moss

Often bright green in color, Roof moss looks like Mother Nature's carpeting on your roof. It has a dense texture and usually grows in dense clumps in shady location on your roof. Roof moss will cause shingles to fail prematurely if it grows underneath them.

Roof Lichen

Roof lichen, seen here in a light green color, grows in bush-like, leafy structures. Lichen clusters can be small or large. The texture can be dry, and crusty which can make it extremely difficult to remove. A low pressure wash pressure washing will remove it.

Roof Algae

Blue-green algae and algae are some of the most common pests that grow on roofs. It looks like a thin film (green, black or white) or shading on the roof, as shown in photo. Its appearance gives the impression of an all-over stained or discolored roof.

Roof Mold

Black roof mold is one of the most problematic pests, when it comes to health concerns. Black roof mold will show in streaks. This is the result of a hardy blue-green algae that has a hardened black look over time. Mold should be tended to immediately.

How can I remove moss, mold, algae or lichen from my roof?

Your most common options are to either hire a professional roof cleaning contractor, power washer ("pressure washer") or DIY.

Let's talk about the first option. Hiring a professional roof cleaning contractor is the best option when you are not comfortable going up on your roof, inexperienced or you do not have the required tools and safety equipment needed to clean the roof safely and effectively. Most people fall into this camp because the majority of homeowners do not have the capability of cleaning their roof the way a contractor would. Using a pressure washer, low-pressure, will deliver the best moss, mold, algae and lichen removal results but a pressure wand in inexperienced hands can cause serious problems to a roof so consider this valid concern. Before hiring a professional to clean your roof, there are questions you'll want to be prepared to ask. See below.

The DIY option is twofold. We have customers who do many of their own household repairs, including cleaning their own roof. These customers tend to be handy, experienced with other large-scale home improvements. Having a walk-able roof is often the case here, in which case they rent or already have a pressure washer to do the cleaning. Then there is the most common homeowner approach, which is a spray and leave on "let Mother Nature" do the work cleaning where Roof Wash is applied in the Fall and goes to work throughout the Fall and Winter and results are seen in the Spring. This method requires patience but it's popular if you're looking for a DIY method and hiring a professional is not a viable economic option. It's also used as a maintenance method for people who want to stay on top of roof cleaning to ensure it doesn't require drastic measure down the road.

Can you clean a roof with bleach? How to clean a roof with bleach?

We strongly caution against the use of bleach to clean roofs and home exteriors. In fact, one of the main reasons Wash Safe™ formulas were invented was to address the problem of how to clean a roof without the use of toxic chemicals. Instead of sharing how to clean a roof, we're going to include below the top reasons you should never clean a roof using bleach.


Over-spray kills plants and trees and it’s dangerous for pets.

When a pressure washer comes to your home, the intention is that the cleaning solution will only be sprayed on your home. Often, this is not the case and over-spray happens and it can kill plants and trees

Bleach will not solve a moss, mold or algae problem long term.

It only makes it translucent by bleaching the stain out. Come next blooming season (usually in the spring) and the homeowner will have to call the roof cleaning company (that uses bleach) again. This happens continuously every 2-3 years. It’s a vicious cycle that feeds off a homeowner’s checkbook while damaging the surrounding landscaping.

Concentrated chlorine such as bleach will destroy plants and the network of life they depend on.

This network provides nutrients and communication plants need to thrive. We saw this video recently and thought it did an amazing job in visually articulating the network of plant life and how our seemingly small decisions and actions have larger consequences.

Bleach can unexpectedly wreak havoc on other parts of your home.

Aside from plants, using bleach on the roof can ruin other parts of the home if the run off if it is not caught by gutters. It can also leave streak marks on the roof where it has discolored shingles.

Bleach is harmful to birds, bees and other wildlife around your home.

If you have your roof washed with a bleach solution, you’ll soon see how effectively it ruins the ecological balance around your home. What a human can smell for a week, the wildlife can smell for a month. Nature is a good thing…. so just say “NO TO BLEACH”.

What is the best cleaner for cleaning asphalt roof shingles?

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Roof, Cleaning, Roof Wash, Wash Safe, How to Clean Your Roof, Moss, Asphalt, Mold, Algae, Moss, Stains, Roof Cleaning Estimates, Cleaner
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Roof, Cleaning, Roof Wash, Wash Safe, How to Clean Your Roof, Moss, Asphalt, Mold, Algae, Moss, Stains, Roof Cleaning Estimates, Cleaner
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Our mission is to provide the world's best and most environmentally conscientious formula to clean your roof. Our Roof Wash is ideal for cleaning and removing stains from moss, mildew, lichen or black algae on roofing shingles including asphalt, metal, tile, wood shake and rubber roofs. It's an oxygen-based cleaner made to remove dirt, debris and stains from moss, mold, algae and lichen. The oxygen-based formula is safe and effective with an active life of only 4-6 short hours before it biodegrades, making it the safest in the industry.  

Do you sell roof cleaning products in bulk or by the pallet?

Yes, Wash Safe™ offers discounts to contractors through our PRO Program as well as discounts on all pressure washing chemicals ordered by the pallet. Email to request PRO Program pricing materials.

How do I know how much roof cleaning product I need?

The way our roof cleaning formula works is for every pound of product used, you will yield up to 1,000 square feet of surface area cleaned. You will increase the product concentration for more dirty, built-up surfaces.


3 LB Roof Wash

up to 3,000 square feet

12 gallons of solution

10 LB Roof Wash

up to 10,000 square feet

40 gallons of solution

40 LB Roof Wash

up to 40,000 square feet

160 gallons of solution

When is the best time of day to clean my roof?

Morning or afternoon is the best time of day to clean your roof. When cleaning your roof, it is best to avoid high heat in the middle of the day.

When is the best time of year to clean my roof?

The best time of the year to clean your roof will vary with every situation. No two roofs are identical and every situation will be different. It depends on what your case. Sometimes an insurance company will demand a roof is cleaned within a number of days or a homeowner is looking to prepare a home for a sale. In these cases, as soon as possible. Otherwise, Spring through Fall works for a total cleaning and Fall is best for a "Maintenance" cleaning. We'll explain the maintenance cleaning more below.



Moss, mold, algae and other fungi; it can destroy a roof. Why is it there? Today's roof shingles have ingredients that provide food as well as water and air supply to these organisms so they are not just surviving — they are thriving, feeding off your roof and turning it into a live fungus garden! Is it destructive? It's ugly. It devalues your home. It lifts shingles which leads to leaks and loss; ultimately shortening the life of your roof. The answer is a resounding yes! As a homeowner, you need to take a proactive strategy to caring for one of your largest investments by cleaning and maintaining your roof. Cleaning your roof can be a hard to solve project but we're going to show you how it can be done safely and effectively using Roof Wash.


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5 gallong mixing bucket for pressure washing






Use extreme caution cleaning your roof. Be careful on ladders and steer clear of electrical wires. If you are not skilled, comfortable or physically able, contact a professional.

Cover and avoid contact with windows, glass and raw metals (copper and aluminum) when spraying. It's best to rinse windows down before and after every cleaning application to avoid run off.

Avoid contact with eyes and prolonged skin contact. Keep out of reach o children and pets. Do not ingest. If swallowed, drink water and seek immediate medical attention.

How to Clean Roof with Roof Wash

The goal is to coat your roof with Roof Wash, which is not an easy task and can be quite dangerous. The safest way to do this is to use some type of pump to spray your roof. If your roof area is walk-able then a garden-style pump sprayer may be all that is needed - however, a steep roof must be sprayed from the ladder. The safest way to do this is to lean a ladder up on your roof above the gutter line. Be sure to use a ladder stabilizer to prevent the ladder from sliding along the gutter! This is the best spot to spray from.

how to pressure wash and clean asphalt and tile roof shingles

Step 1: Determine How Much Roof Wash You Will Need to Clean Roof

See our Roof Cleaning Chemical Calculator above to determine how much undiluted solution you will need to purchase. When you have your product you will mix in a 5 gallon bucket, plastic drum or trash barrel, mix as directed with warm to hot water. Stir frequently for 15- 20 minutes to activate the solution.

Step 2: Prepare to Spray Roof Cleaning Solution with Transfer Pump

(A garden pump sprayer could also be used.) All pieces of equipment recommended can either be purchased at your local hardware or rented. We recommend pouring the product into a pump sprayer or place submergible pump into the solution attaching a 25 foot garden hose and spray nozzle to the outgoing end of the pump. This is best done with 2 people, one person stays with the bucket of solution and pump and one person should be up on the ladder with the end of the hose and a spray nozzle open when starting the pump to create air/solution
flow. Time to spray....

BE 1

Step 3: Turn Pump on and Begin Spraying the Roof with Roof Wash

Start by aiming at the highest point and letting the solution run
down over the roof. Be sure to coat the entire roof! There are 2 ways to go about rinsing off the solution.

For best results: rinse off immediately with the use of a pressure washer. Your pressure washer must always be aimed down the roof using the water pressure at 300-500 PSI max to avoid scarring and simply rinse clean .

Maintenance Method: Another -easier- way is letting Mother Nature do the rinsing with gradual results over time. See how to under "Mother Nature Rinse". This is also the recommended method for those who are not comfortable or physically able to get up on a roof.

Need professional help? If hiring someone to do the job is what you would rather do, a roof cleaning contractor can be found in every state now, but if you can't find one, we would be glad to speak to your local handyman and go over the cleaning process with them, just call us.


How do I do the Mother Nature Rinse?

In this instance, you'll let the application dry for an hour or two then repeat the process. This ensures good absorption. Leave the product on for the rain to wash off. After the first significant rainfall, you should see up to an 80% difference. The roof will eventually be 100% clean after. Please keep in mind that because two applications may be necessary, you may need to purchase double to amount of formula so you have enough for both applications.

How do I keep my roof clean throughout the seasons?

You can clean your roof naturally (without pressure washing) by letting the rain do it using the Mother Nature method which is explained above. Apply a coat of Roof Wash yearly or bi-yearly. Consider bi-yearly if water is nearby, if there is a lot of shade or trees, if your roof faces north, if your neighbor is infected or if you live in a humid climate. The best time of year for maintenance cleaning is Fall so winter's rain, snow, sleet, etc; can help clean the roof. No spraying necessary —the rain does the work!

Should I use cold, warm of hot water to clean a roof?

Warm is best but you can use cold if you do not have access to warm water. The product works because of the oxygen, it develops when it is mixed with water. The oxygen needs time to warm.

Do I apply the product to a wet or dry surface?

Our products are designed to be applied to a completely dry surface. If the surface is wet, it makes it difficult for the product to adhere to it. It's key that the product adheres to the surface in order to go to work on the moss, mold, algae and lichen. A dry surface is optimal for the products to deliver the best results.

Why can't I apply the product using a pressure washer?

You can only rinse with a pressure washer. Foaming action helps the product to stay on the surface to work. Putting it
through a pressure washer or a soap type siphon dilutes the product .It also does not give it enough time to be activated. The product works because of the oxygen. It develops when it is mixed with water. The oxygen needs time to form.