Roof Cleaning 101 - The Complete Guide - Wet & Forget Blog (2023)

Roof Cleaning 101 – The Complete Guide

By Wet & Forget

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Regular roof cleaning and inspections are critical for maintenance of any roof.

Read on to learn how to ensure you are keeping up with a robust preventative maintenance program, how to inspect your roof, and how to clean your roof – whatever its material.

Basic Preventative Maintenance

Roofing professionals recommend establishing a regular preventative maintenance program for your roof. This should consist of roof cleaning and inspections twice a year, ideally in the spring and autumn.

A robust roof maintenance program can help preserve the longevity of your roof and keep significant issues to a minimum.

Regular roof inspections are critical for ensuring potential issues are identified before they reach a crisis point. This not only helps prevent catastrophes but also affords homeowners the time to incorporate any necessary expenses into their budgets.

It also allows more time to file and process any essential warranty claims before repairs.

Regular roof cleaning can help preserve your home’s aesthetic and resale value. More importantly, it also minimizes the risk of any damage to your roof or voiding of its warranty.

Dirt, sap, and other debris on your roof can result in more than just a cosmetic issue. The accumulation of such organic material promotes the growth of moss or lichen.

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Moss and lichen both retain moisture that can severely damage your roof. Unchecked moss growth may void some roofs’ warranties and even your homeowner’s insurance, making it even more problematic.

Regular Roof Inspection

Inspecting your roof for any potential damage, defects, or buildup of debris and organic growth is critical to a robust preventative maintenance plan for your roof. Homeowners should conduct visual inspections twice annually, as well as after any major disasters or weather events.

Key things to look out for during your review include:

  • Damaged or cracked caulking around flashing
  • Rust spots on flashing
  • Shingles that are buckling, curling, or blistering
  • Missing or broken shingles
  • Cracked or worn rubber boots around vent pipes
  • Significant amounts of grit from the roofing material (mainly asphalt) in gutters
  • Moss or lichen

Whether it is feasible or not for a homeowner to get up on the roof to conduct an inspection will depend on the type of roof and level of comfort of the homeowner. Steep-slope roofs, especially those with delicate shingles, are highly susceptible to damage caused by improper weight distribution.

Avoid walking on such roofs when possible. When using ladders on steep-slope shingle roofs, match the pitch of the ladder to that of the roof. This will distribute weight evenly and minimize the chance of accidental damage.

If regular inspections at roof level are not viable, homeowners can conduct visual inspections from the ground using binoculars.

Regular Roof Cleaning

Clean your roof by removing any debris and dirt that may have accumulated from valleys, snow guards, gutters, and the area behind the chimney. Use heavy rubber gloves to scoop up materials in areas you can safely reach.

Use a vinyl rake to clear areas you can’t reach. Take note of any overhanging tree branches and trim them away from the roof.

Remove moss, mold, mildew, and algae with a safe, gentle outdoor cleaning product compatible with your roof like .

Wet & Forget Outdoor Cleaner only needs to be applied once a year to remove the growth. It requires no pressure washing, scrubbing, or use of harsh chemicals that could damage your roof.

Here’s how to apply it:

(Video) Cleaning with Cordless Sprayer and Wet & Forget // Part 1

  1. Connect the Xtreme Reach™ Hose End Nozzle to your garden hose and attach the jet-setting tip.
  2. Turn the dial to the ‘ON’ setting and saturate the affected area with the diluted Wet & Forget at a time that allows the surface 4 to 5 hours to dry before the threat of rain.
  3. Walk away, and let Wet & Forget annihilate the moss, mold, mildew and algae.
  4. Re-treat once a year, or at the first sign of re-growth.

Tailoring Your Roof Cleaning Program to Your Roof

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Asphalt Shingles

Asphalt shingle roofs are the most common type of residential roofs in the United States. They are known for being low-maintenance, and the maintenance program outlined above should be sufficient to care for them.

While no additional steps are needed, it is important to remember to avoid pressure washing asphalt shingle roofs. High pressure can severely damage shingles.

It is also advisable to avoid using harsh products like bleach that could discolor or prematurely degrade the shingles.

Be sure to keep an eye out for granules from your asphalt shingles collecting in gutters. While this is common on new roofs, it could indicate an older roof is nearing the end of its lifespan.

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Clay & Concrete Tile

Cleaning tiles with harsh chemicals and pressure washers can erode tile coatings and paint. Roof cleaning in such abrasive ways makes it necessary to re-coat the seal and paint to protect the roof from dirt and moss infestation.

Avoid using such measures when possible. Tiles are also very fragile and can crack easily under pressure.

It is important to avoid walking on tile roofs. If it is necessary to be on your tile roof, use plywood with a foam treatment on its underside. This will lessen the pressure and distribute your weight.

Tiles may take on efflorescence (a whitish, chalk-like covering) as they dry. This is a result of salts crystallizing as water evaporates.

Higher levels of humidity slow the evaporation of water which allows the salts to crystallize into efflorescence. Efflorescence does not damage tiles but will dull them.

To remove efflorescence, add buffing your dry roof with a clean and dry cloth rug to your regular roof cleaning and maintenance program.

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Wood Shake & Shingle

Maintain wood shakes and shingles with care. Improper roof cleaning practices can easily damage wood shakes and shingles.

It is important to avoid pressure washing your wood roof. Pressure washing can cause wood shakes and shingles to lift or can trap water underneath them, causing leaks.

It is also advisable to avoid using harsh chemicals like bleach or ammonia in wood roof cleaning. Such products may discolor paint and metal fixtures on your roof, and runoff may damage your garden and lawn.

It is critical to ensure swift removal of any moss or lichen on your wood roof. Moss growth on wood shingles or shakes has the potential to void your roof’s warranty.

Add trimming back any branches hanging over your roof to your regular maintenance schedule. This will minimize the accumulation of debris on your roof and will help to prevent the growth of moss.

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Cedar Shake & Shingle

Cedar shake roofs have special needs different to that of other wood shingles but are similar in their cleaning and maintenance needs.

The Cedar Shake & Shingle Bureau recommends ensuring overhanging branches are kept trimmed away from cedar roofs to prevent debris and moisture buildup. It is critical to keep cedar clean to allow it to breathe.

Clean gutters and downspouts during your biannual inspections and cleaning. Ventilation is crucial to keeping your cedar roof in good shape.

Ensure that areas with louvers, ridge vents, roof vents, and soffit vents are clear and free of any blockage.

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Avoid pressure washing your cedar roof. Pressure washing should only be done by a trained professional in cases of extreme moss and debris build-up.

Avoid products like bleach and ammonia, as they may discolor or prematurely weather cedar shakes.

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Slate Shingle

Slate shingles are a beautiful material for roofing but are delicate and costly to replace.

Regular roof cleaning is critical for your roof, as slate is easy to cleave and water absorbent. Buildup of moss and debris on slate roofs hold moisture in the slates that can split them during winter.

When cleaning a slate roof, don’t use chemicals like ammonia or chlorine bleach. Such harsh chemicals are incompatible with the copper components of your slate roof.

They can turn your copper prematurely black or discolor a beautiful verdigris patina. It is also important to never pressure wash your slate roof or even use too strong a blast from a garden hose.

Pressure washing can break apart slates or drive water up under slates and cause leaks.

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Metal roofing is durable, but it is vulnerable to rust and corrosion. It is also important to prevent different types of metal from touching one another. Chemical reactions between metals can damage or discolor the metal.

Ensure your metal roof is kept clean and well maintained by using products that are safe for the type of metal your roof is made of, and look out for any areas that have begun to rust or corrode during your inspections.

(Video) Wet And Forget Outdoor Cleaner Hose End - Reach Up To 30Ft - No Scrubbing - Safe For All Surfaces

At the end of the day, the most important thing for any roof is to inspect and clean it of any visible debris or growth twice a year.

Roof cleaning can be made easier with a once a year, no-fuss application of. This outdoor cleaner is safe to use on virtually any type of roof and will help to keep your roof free of moss, mold, mildew, and algae all year long.

To find a Wet & Forget retailer near you, click here.


Does wet and forget really work on roofs? ›

Roof cleaning can be made easier with a once a year, no-fuss application of Wet & Forget Xtreme Reach™ Hose End. This outdoor cleaner is safe to use on virtually any type of roof and will help to keep your roof free of moss, mold, mildew, and algae all year long.

How long does it take for wet and forget to work on roof? ›

It depends on the type of growth and the intensity of the contamination. If it's a new growth or a small amount of staining you can see results within days. Otherwise, it may take 2-3 months to see improvement. In the very worst case scenario, where contamination is extreme, it may take 6-12 months to work.

What do professionals use to clean roofs? ›

In addition to bleach, sodium hydroxide, potassium hydroxide, calcium chloride, and percarbonate cleaners are each commonly used. None of those cleaners is as aggressive (or as corrosive) as bleach.

Will wet and forget remove moss on roof? ›

Wet & Forget is gentle enough to use on a wide variety of outdoor surfaces, including any type of roof, decking, or siding. Wet & Forget works with the rain and wind to gently remove moss off your roof. No scrubbing, bleach, or pressure washing needed!

How long should wet and forget sit? ›

Temperatures need to be above 32 degrees during application and for approximately 5 hours after. Reaction Time: Once treated with Wet & Forget, green growths such as algae will clean up within a few days or weeks in most cases. Black stains caused by mold and mildew can take a month, sometimes several months.

Do you have to rinse wet and forget? ›

Wet & Forget Outdoor banishes both green and black stains from your home's outdoor surfaces. Just spray it on and forget it! Wet & Forget does the cleaning for you – no scrubbing, rinsing, or power washing required.

What happens if it rains after applying Wet and Forget? ›

If it rains 4-5 hours after you apply the Wet and Forget, you will need to reapply once it is dry again.

What's better than Wet and Forget? ›

Bio-Shield will give a powerful, rapid kill of moss, fungal, algal and lichen growths, and can prevent re-growths. It can be used to clean any exterior surface.

How long before rain should I apply Wet and Forget? ›

Apply Wet & Forget on a cool, dry, windless day, with no rain in the forecast for 4-5 hours. Often the evening or early morning is the best time to apply; when evaporation is minimal. This way, the treated surface stays wet with Wet & Forget for an extended period.

What precautions should be taken during wet and forget? ›

Wash thoroughly after handling. Do not get in eyes, on skin, or on clothing. Empty containers retain product residue, (liquid and/or vapor), and can be dangerous. Keep container tightly closed.

Is Wet and Forget better than bleach? ›

Wet & Forget Outdoor products lack phosphate and bleach, and their neutral pH levels allow them to clean gently. On the other hand, bleach has a pH level of 13, which can damage outdoor surfaces and make them more susceptible to organic growth.

What is the fastest way to clean a roof? ›

The ARMA recommends a 1:1 ratio of bleach to water to clean a roof. They also advise against using a pressure washer on asphalt shingles, as the force of the water can damage them. After being allowed to sit on the roof surface for up to 20 minutes, the bleach solution should be rinsed away with clean water.

What is the best chemical for cleaning a roof? ›

Experts agree that sodium hydroxide is the product of choice for homeowners who want to clean their concrete, tile, and the materials of their slate roof. Another chemical solution that can be used for cleaning your roof is sodium hypochlorite. This substance turns into salt when all traces of water have evaporated.

Does bleach hurt roof shingles? ›

"One of the best cleaners is liquid household bleach," Dorman says. "And it doesn't damage the shingles." Apply a 75 percent solution of household bleach (three parts bleach to one part water) to asphalt shingles. Use one gallon of solution per 30 to 50 square feet of roof surface.

What temperature can you apply wet and forget? ›

Apply the Wet & Forget Concentrate or Ready To Use when the temperature is above freezing (32° F). Use the Wet & Forget Hose End to clean up mold and mildew when the outdoor temperature is above 55° F.

What time of year is best to remove moss from roof? ›

The best time to treat roof moss is when it's actively growing. Moss grows very little in summer, but it kicks into high gear during fall rains, moderate winters and early spring months. Treating right before peak fall rains is perfect timing for roof moss treatments.

What is the mixing ratio for wet and forget? ›

Wet & Forget's mixing ratio is 1 part Wet & Forget to 5 parts water. For a 1-Gallon sized garden pump sprayer, pour 20 oz (2.5 cups) of Wet & Forget into your sprayer. Next, fill the sprayer with water to the 1-Gallon marker and you're ready to go.

What is the main ingredient in Wet and Forget? ›

The active ingredient in Wet & Forget Outdooris alkyl dimethyl benzyl ammonium chloride. This ingredient is present in many common household sprays and in anti-bacterial wipes.

What is the active ingredient in Wet and Forget shower? ›

dimethyl benzyl ammonium chloride

What is the same as Wet and Forget? ›

Bio-Shield was tested and certified by two separate laboratories, Labtec and Hill Laboratories, in October 2014 to have the same active component as Wet and Forget.

What are the hazards of wet and forget? ›

Ingestion can cause burning pain in mouth, throat and abdomen - May be fatal if ingested. Skin Contact: Harmful if swallowed. May cause severe and permanent damage to the digestive tract.

Does wet and forget remove black spot? ›

Wet & Forget's gentle and effective cleaning formula works with the wind and rain to remove ugly black and green stains and leaves your outdoor surfaces clean and growth-free for up to one year – or longer. No rinsing, scrubbing or power washing is needed.

Can you spray wet and forget at night? ›

It's best to apply Wet & Forget on a dry day with no or little wind - preferably in the morning or evening to avoid evaporation of the product.

Does sun help Wet and Forget? ›

For roof applications, we recommend starting your spraying in the early morning so the sun doesn't have a chance to heat up your roof before applying. Avoid applying the product on a windy day as some of the product may drift away, making application and cleaning less effective.

Does Wet and Forget remove mold? ›

Wet & Forget Outdoor removes moss, mold, mildew, and algae on exterior surfaces. It's a gentle cleaner that doesn't require any scrubbing, and its bleach-free formula is safe to use on all types of headstones.

Is wet and forget the same as 30 seconds? ›

30 Seconds "Spray and Walk Away" contains the same active ingredient as "Wet and Forget". Wet and forgets has a diluted option for the next purpose of indoor use. Wet & Forget was developed over 30 years ago as an effective mould, lichen and algae remover. Just spray it on, wait for 10-15 minutes, then hose it off.

Can you put wet and forget on your car? ›

Wet & Forget Outdoor safely removes algae and moss from your vehicle's exterior surfaces, including: Exterior paint. Metal. Chrome.

What do professionals use to clean roof shingles? ›

Sodium Hypochlorite (bleach)

Called SH for short, household bleach is the most widely used roof cleaning chemical, as it is the choice cleaning agent of nearly every pressure washing company in North America.

Can you use vinegar to clean a roof? ›

There are several sprays you can use to kill moss growth on your roof. Vinegar or a 50/50 chlorine bleach and water solution are commonly used and are very effective.

How do you make homemade roof cleaning solution? ›

Make Your Roof Cleaning Solution

In the pump sprayer, create a 50/50 mix of water and 10% pool chlorine. Add a tablespoon of dish soap. This will help the solution to stick to your roof giving it time to kill the algae.

Can I walk on my roof to clean it? ›

While it is OK to walk on your roof, it is not recommended and should be avoided whenever possible. Though you might be able to fix the leak or hang Christmas lights as a homeowner by walking on your room, there are serious safety and insurance risks involved in stepping onto your roof yourself.

What chemical is used to soft wash roofs? ›

When professionals think of soft washing roofs and siding, the top cleaning chemical used is a professional-grade 12.5% sodium hypochlorite, or bleach, mixed with water.

Does spray and forget work? ›

Spray & Forget has a residual effect and actually adheres to the applied surface. In addition, Spray & Forget, unlike other cleaning methods such as pressure washing, will continue to clean long after the stains cannot be seen by the naked eye. That means that the stains will be completely removed.

What is the white powder on roof after cleaning? ›

When driving by a neighbor's house, have you ever wondered, “Why is there white powder on their roof?” In short, it is known as zinc sulfate powder which is used to deter roof moss. Zinc deterrents often come in two forms, a zinc strip, or zinc sulfate powder.

Will vinegar clean roof shingles? ›

Clean shingles with vinegar

The next method is to apply the vinegar to the roof using a spray bottle. This method will remove any remaining debris or moss from the roof without damaging it. Another way to clean the roof is to mix a mixture of vinegar with a small amount of dish soap.

What is the mixture for bleach roof cleaning? ›

The Asphalt Roof Manufacturing Association (ARMA) says that "The most effective method of cleaning algae and moss from a roof is with a 50/50 (i.e., 1:1) mix of LAUNDRY strength liquid chlorine bleach and water.”

Will vinegar harm shingles? ›

Vinegar is safe to use on shingles, as it does not damage nearby paint or landscaping. If you want to remove mortar and other stains from your shingle roof, you can use muriatic acid to do so. However, be careful, because this acid is toxic to the eyes and skin and will damage your building and the plants below it.

What happens if you don't remove moss from roof? ›

Left untreated, the clumpy greenery can cause virtually any roofing material to degrade—most commonly wood and asphalt, but also metal, clay, and concrete—and thus drastically shorten its lifespan.

How do I get rid of moss on my roof without scraping it? ›

Chlorine bleach removes mosses, fungi, and mildew, but it may damage plants, so dilute it before you spray it on your roof. A good formula is to mix one quart bleach with one gallon of water and 1/4 cup heavy-duty cleaner, like trisodium phosphate.

How long does wet and forget take to work on a roof? ›

If it's a new growth or a small amount of staining you can see results within days. Otherwise, it may take 2-3 months to see improvement. In the very worst case scenario, where contamination is extreme, it may take 6-12 months to work.

What do roofers install on your roof to repel water? ›

Roofing felt is comprised of a base, made from natural materials (such as wood cellulose) or synthetic ones (such as fiberglass or polyester), and then coated or saturated with a protective coating such as bitumen (asphalt), which repels water but still allows the product to breathe.

What is the best water repellent on the roof? ›

Bitumen is a good waterproofing material due to its nature. It is easy to apply and economical. Bitumen-based liquid membrane and bitumen-based roll membrane materials are the most well-known, economical, and high-performance materials used for roof insulation.

What kills mold on roofs? ›

Use Basic Chemistry. The most cost-effective way to treat your roof is to spray-wash it with a 50/50 mix of bleach and water. You can buy pre-made solutions, but it's much cheaper to mix it yourself.

How do you clean a roof without damaging shingles? ›

DON'T use a pressure washer, which can loosen shingles and seriously damage your roof. DO use a sprayer attached to a garden hose that's filled with equal parts chlorine bleach and water of laundry strength liquid chlorine bleach and water. This is the best way to clean a roof with asphalt shingles.

What happens if roof underlayment gets wet? ›

It is not a sponge-like material, as it repels water more than it absorbs it. Fortunately, roofing felt can get wet and still maintain its integrity. However, because it is meant to repel water and not absorb it, it can break down if it stays wet for too long, so it must have time to dry out.

How do you waterproof a roof from the inside? ›

All you need to do is take a putty knife and apply a liberal layer of roofing tar or bitumen paint to the leaking hole. Then, press a shingle to the tar or paint and spread more around the edges. This will help to keep it in place.

What is used to remove water from the roof to the ground? ›

Gutters are designed to collect all that rainwater and dump it onto the ground. You'll want a gutter system that steers rainwater away from your home since rain is the primary cause for leakage.

Which waterproofing is best for old roof? ›

The best option which is Polyurethane Coating. The procedure involves surface preparation with wire brushing followed by cleaning and filling the exposed cracks with elastomeric material. Then priming the surface for better adhesion of the PU coating.

What is the difference between water repellent and water sealant? ›

Water repellents: Unlike sealers, water repellents penetrate into the masonry, coating the cracks, holes, nooks, and crannies of the bricks and mortar. By doing this, a continuous barrier is not formed but the masonry is still protected against water.

What do they spray on roofs to make them last longer? ›

A Silicone Restoration Membrane (SRM) is a fluid-applied silicone coating sprayed directly onto an existing roof system. The process of installing a silicone restoration membrane is relatively straightforward.

What kills mold the fastest? ›

In such cases, a solution of diluted bleach provides the fastest way to kill mold on walls or flooring. Prepare the solution by adding one cup of bleach into a bucket that contains about a gallon of warm water. Then proceed to scrub the mold vigorously with a stiff-bristled brush you've dipped in the bleach solution.

What kills the root of mold? ›

To kill mold spores and their roots, pour straight 3 percent peroxide, undiluted, into a spray bottle and saturate the blocks with it. Let the peroxide do its work for 10 to 15 minutes, and scrub the walls to remove all dead mold. You can add vinegar to the peroxide in the spray bottle to make the solution stronger.”

Does bleach harm shingles? ›

"One of the best cleaners is liquid household bleach," Dorman says. "And it doesn't damage the shingles." Apply a 75 percent solution of household bleach (three parts bleach to one part water) to asphalt shingles. Use one gallon of solution per 30 to 50 square feet of roof surface.

Does vinegar damage roof shingles? ›

The first is to mix vinegar with water in a ratio of one part vinegar to three parts water. This will ensure that the vinegar covers the entire roof area. The next method is to apply the vinegar to the roof using a spray bottle. This method will remove any remaining debris or moss from the roof without damaging it.


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