How much does it cost to clean a roof?

Reviewed by Cristina Miguelez remodeling expert. Written by Fixr.com.

The roof of any home is continuously exposed to the open air and elements. Therefore, dirt and debris may build up over time, along with marks, stains, mold, and moss. As time goes on, this accumulation of dirt and plant life can lead to serious damage, which is why it is important to have it professionally cleaned regularly.

The national average cost to clean a roof is between $450 and $700, with a typical homeowner paying an average of $612 for a pressure washing of a 1,500-square-foot roof. On the low end, prices run as low as $173 for a chemical clean of a 200 sq.ft. roof and on the high end, it can cost $1,326 to soft-wash a 1,500 sq.ft. roof.

Cost to Clean a Roof

Roof Cleaning Cost per Square Foot

Many cleaning contractors charge per square foot for a roof cleaning project, so the bigger your roof is, the higher the cleaning costs. In general, expect to pay anywhere from $0.10 and $0.60 per square foot for professional cleaning, but the exact price depends on various factors like your location, cleaning company, and type of cleaning.

Roof Cleaning Prices by Method

When it comes to roof cleaning, there is more than one way it can be done. Cleaners use various methods and adjust their approach, depending on the roof’s condition and cleanliness. For example, if it' covered in moss, it may require a different cleaning method than one that is just a little dirty. The table below shows various cleaning methods and average costs:

Roof Blow

The average cost for a roof blow is $0.05 to $0.10 per square foot. This is the simplest kind of cleaning, where a leaf blower or other blowing device is used to blow away any leaves or debris that may have settled on the surface. It is a good option for general cleaning on homes with lots of trees nearby, but it will not be very effective against stubborn marks or moss.

Zinc Oxide Application

The average cost for zinc oxide application ranges from $0.05 to $0.15 per square foot. Zinc oxide application is a popular choice on surfaces that are prone to growing moss and algae. Zinc is a toxic substance for moss and lichens, preventing them from growing in the first place. Professionals can even apply zinc strips to your roof or dust it with a zinc oxide powder. It is a good choice for very rainy areas where moss grows more easily, but the strips need to be replaced every few years.

Roof Chemical Wash

The average cost for zinc oxide application ranges from $0.05 to $0.15 per square foot. A chemical wash, also known as a non-pressure wash, involves spraying a chemical cleaning solution. The solution may be lye or sodium hydroxide and will kill lichens and algae. Usually, it does not pose much risk to your roof, but the chemicals can damage weak tiles. So, it should be thoroughly checked over for weakness before starting this cleaning. It also will not clear away debris, so it is best-suited for mossy surfaces.

Pressure Wash

The average cost to pressure wash roofs is between $0.20 and $0.70 per square foot. Pressure washing is the most popular and common form of roof cleaning. It involves using a pressure washer to blast high-pressure unheated water, getting rid of debris, dirt, stains, and some moss and algae. On the downside, the high-pressure nature of this cleaning method can potentially damage any weak tiles or shingles you might have. And, it will not kill moss at the core, so a chemical-based clean may be needed if your roof has a lot of plant life on it.

Power Wash Roof

The average cost to clean roofs with a power wash ranges between $0.20 and $0.70 per square foot. Power washing uses high-pressure streams of extremely hot water to remove dirt, moss, and other debris from a roof or other surface. It removes mildew, mold, salt, and more. The addition of heat makes it excellent at removing any debris that is adhered to the roof. It can also kill moss through huge blasts of hot water directed in their location.

Low-Pressure Roof Cleaning

The average cost for low-pressure cleaning is between $0.30 and $0.70 per square foot. It is really similar to a pressure wash, but it uses gentle chemicals. This cleaning method is more gentle while also being more thorough. It kills moss and algae and rinses away dirt and debris. It will not be quite as effective on stubborn marks and stains, but it is a good choice for an all-over roof clean and will not pose much risk to its structural integrity.

Soft Wash Roof Cleaning

The average cost for a soft wash cleaning ranges from $0.30 to $0.75 per square foot. The soft wash technique is becoming more popular with homeowners around the world due to its in-depth approach. It is quite similar to a pressure washing clean but is extremely low pressure and involves using chemicals, bleach, soap, and water to clean. For a typical soft wash, a diluted bleach solution is first applied, killing any moss, lichens, or algae, as well as cleaning the roof of bacteria and killing most everything in sight. Then, it is rinsed off with water.

Roof Cleaning Cost by Material

Roofs come in a wide range of materials, including metal, wood, and asphalt shingles, and the right form of cleaning varies depending on the material. The best cleaning method depends on its material. For instance, some materials like metal can handle a high-pressure wash with tons of power, while others (like rubber) do better with a chemical wash. The table below shows the best form of cleaning for each material, along with average costs:

Rubber

The average cost to clean rubber roofs is $0.20 to $0.30 per square foot. They are not very prone to developing moss and lichens, but they can get dirty and stained. So, a simple chemical wash with diluted bleach is usually the best option. This will clear away the marks and leave the rubber membrane looking as good as new. Low-pressure cleaning is another method commonly used. A cleaning solution is introduced before being rinsed with a large amount of water. This removes debris and restores energy efficiency to the material.

Tar and Gravel

Professionals often favor the use of bleach on tar and gravel roofs. A typical chemical wash costs between $0.20 and $0.30 per square foot. A tar and gravel roof is also best-suited to a chemical wash that rids moldy spots and mildew patches. In many cases, plastic rakes or leaf blowers are used to remove any moss build up. The chemical treatment can then be done to ensure the surface is clean and in great shape.

Metal Roof Cleaning

The average cost for metal roof cleaning is between $0.20 and $0.70 a square foot. They are very strong and resistant, so they can withstand the high-powered blast of a high-pressure wash. This removes dirt and debris and rids the surface of most moss and lichens. Metal is capable of handling hot water pressure washing. This will be better suited to removing debris, moss, and other items from the roof’s surface.

Wood

The average cost to clean wood roofs ranges from $0.30 to $0.70 a square foot. One of the issues with this material is that it does not always stand up well to high-pressure blasts of water. The best option is a low-pressure wash that will not risk damaging the material but still provides a thorough clean. Professionals use specially selected chemical solutions that are gentle to the wood and tough on moss. This can be used to remove lichen, moss, and other debris.

Slate Roof Cleaning

The average cost for a low-pressure wash of a slate roof is between $0.30 and $0.70 per square foot. With slate roofs, the tiles are quite heavy and sturdy, but a low-pressure wash is still best because individual tiles can easily become dislodged when exposed to high-pressure blasts. This cleaning method removes years of growth and debris from the surface.

Clean Roof Asphalt Shingles

Soft wash cleans the surface without risking damage to the tiles, costing around $0.30 to $0.75 per square foot. If you have an asphalt shingle roof, a soft wash is the best option. Asphalt shingles are soft and malleable, so they must be handled with care. A high-pressure wash will usually cause problems such as damaging the roof or loosening the shingles. Algae and moss are common on this material, so regular cleaning is necessary.

Concrete

Expect to pay between $0.30 and $0.75 a square foot for concrete roof cleaning. For this type of roof, a soft wash is a good choice. This material is typically used in wet and rainy places where lots of moss and lichens grow, so you need a chemical solution to get rid of them. High-pressure washing should be avoided since it can damage the concrete, shorten the life of the roof, or remove granules from its surface.

Tile Roof Cleaning

The total price for this tile roof cleaning is between $0.30 and $0.75 per square foot. Whether you have ceramic or clay tiles, these materials are delicate and do not stand up well to high-pressure cleanings. The best option is a soft wash that provides a thorough yet gentle clean. ​It removes moss and algae without causing the tiles to chip, crack, or break.

Vinyl

The average washing cost for vinyl roofs ranges between $0.30 and $0.75 per square foot. The most appropriate cleaning method is a soft wash, which is less intense than a high-pressure wash. The soft wash process removes dirt and debris with low-pressure washing. It is similar to the force that might be created using a home garden hose. This prevents any damage to the material while ensuring it looks great when the process is complete.

Solar

Washing prices for solar panels typically fall between $0.30 and $0.75 per square foot. High-pressure washing should be avoided since it can crack or damage the solar panels. Instead, a soft wash is the perfect option for this material. A soft wash thoroughly washes and sanitizes the panels without worrying about damage. This method is ideal for removing lichens, algae, and moss from the solar panels.

Plastic

The cleaning cost for plastic roofs runs between $0.30 and $0.75 for every square foot. This kind of material benefits most from a soft wash. These roofs get dirty quickly if not cleaned regularly. A soft wash removes twigs, leaves, moss, and other materials that should not be on the surface. Gentle tools should be used for the process since rough items can damage the coating.

Clay

For clay roofs, soft wash cleaning prices range from $0.30 to $0.75 per square foot. This material does best with a soft wash rather than something more intense. Using the right cleaning method is crucial since clay lasts many decades when well maintained. Once the cleaning process is complete, buffing the clay is typically done. This makes them look brighter because the cleaning process may dull their appearance.

Roof Moss Removal Cost

Moss is one of the biggest issues for homeowners to worry about on their roofs. It might look harmless in small quantities, but it can grow fast and cause serious damage, adding moisture to your roof that can cause tiles to degrade. It can also potentially grow over into the gutters and block them. Moss even absorbs heat, which can affect how much you spend on energy bills throughout the year. Most forms of cleaning incorporate moss removal, such as chemical cleans and soft washes. This means you usually will not pay anything extra for moss removal, as long as you choose the right kind of cleaning. This costs between $0.20 and $0.70 per square foot.

When it comes to moss removal, the sooner, the better. Many experts say that as soon as moss is spotted on the surface in any quantity, call a professional. Others say that tiny amounts of moss are not too urgent, but the longer you leave moss, the more it will grow, especially in rainy areas. It is best to act fast and minimize the risk.

Roof Moss Treatment

Most professional cleaners clean moss off during the cleaning process, either through low-pressure cleaning, soft washing, or chemical cleaning. They may also offer to apply a special treatment to prevent the moss from coming back again. This can be a good choice because it minimizes the necessity for repeated cleans in the years ahead. Even though it has an initial cost of about $150 to $250, it can save you money in the long term.

Roof Cleaning and Coating Cost

Some cleaners offer to coat your roof, which provides it with an added layer of protection against the elements and may save money due to fewer cleanings. By coating it, you are making it waterproof, and some coatings make it flame-resistant, corrosion-resistant, and heat-reflective. With all these advantages, coated roofs can last several years longer than a non-coated one. The cost of coating depends on the coating type you choose, ranging from $0.50 up to $5 per square foot.

Factors Affecting the Cost to Clean a Roof

Various factors impact the cost of cleaning your roof, starting with its size. Naturally, larger ones require more time to clean on average, so professionals usually charge per square foot. Expect to pay a higher price if you have a larger-than-average roof. The cleaning method factors into how expensive the cleaning project is. There is also the material to consider. Some materials like wood or tile need to be treated with more care and attention than others. This creates the need for additional labor, which may increase the price of having a roof professionally cleaned. Other cost factors include the slope and whether the home has multiple stories. In both of these cases, costs can increase. On average, it costs about $0.10 more per square foot for a multi-story home roof cleaning.

Signs That You Need to Have Your Roof Cleaned

Several signs indicate that it may be time to have your roof cleaned. Regular cleaning is essential since it ensures it looks excellent. In addition, routine maintenance removes dirt and debris, removes leaves and twigs from the gutter, and provides a way to address any other areas that are overly dirty. If you notice moss, fungus, or algae on the roof, that is a sign you need to have it cleaned. Black streaks are one sign of mold that indicate the need for cleaning. Lifted roofs shingles also indicate an issue with buildup underneath the surface.

How Often Should You Clean Your Roof?

One factor that impacts how often you clean your roof is your location and the surrounding environment. If you live in a rainy area, there is a higher chance of algae and moss growing on your roof, so it may require more regular cleaning. Those who live by the beach may also find that it may be regularly damaged by the salty air and needs to be cleaned more often. If you live in an area with lots of trees nearby, leaves and debris are more likely to build up on the surface, which also leads to the need for more frequent cleaning. Even if there are no signs of dirt or growth, a professional cleaner should maintain it annually. If problems are apparent, more frequent cleaning may be needed.

Enhancement and Improvement Costs

Stain-Blocking Solution

This chemical solution may be applied after the roof has been cleaned to protect the surface against future stains, minimizing the need for future cleans. You can buy a stain-blocking solution or ask your cleaner to provide it, paying about $20 to $30 per gallon. A single gallon covers about 200 - 300 square feet of roof surface.

Roof Painting

Painting a roof can be a good way to prevent the build-up of moss in the future, as well as adding an extra layer of heat insulation to reduce your heating costs throughout the year. The costs for this vary depending on its type and size, but prices usually range from $1 to $3 per square foot.

Gutter Cleaning

When cleaning your roof, some companies may also offer to clean your gutters, and if you combine these services, you may be able to negotiate a good discount. Separately, the average cost for gutter cleaning is about $150, but you might work it down to $100 or less by talking with your cleaner.

Roof Repair

Sometimes, a roof cleaning brings to light issues that need to be cleared up. This is when a homeowner needs to seek a professional for roof repairs. For instance, the roof might be leaking or have holes, blistering, and cracking. Sometimes cleaning can cause or exacerbate roof issues, especially when the wrong cleaning method is used. The average cost of roof repair ranges from $300 to $1,500.

Additional Considerations and Costs

• Loyalty discounts. If you can find a good-quality roof cleaning company, it is worth sticking with them. Many companies offer discounts for repeat customers.
• Shingle replacement. If you notice black streaks on your roof that have been around for a few years or moss that has grown several inches tall, the shingles may be seriously damaged underneath and could require replacing. This is why it is vital to act fast when you see any stains or moss on the surface.
• Paint drips. If you accidentally get any paint on your roof shingles that needs to be removed, use a regular latex paint stripper and wet rag to quickly wipe it away. If you wait too long and the paint dries, the job can be more difficult, and it may be simpler to replace the affected shingles.
• Best time to clean. The best time to clean a roof is during the summer because the dry and clear conditions make the job easier. However, if you live in a rainy area and have a lot of moss, you may need to wait to clean it until either the fall, winter, or spring because moss goes dormant during the summer months and is much harder to get rid of.
• DIY. You can clean a roof on your own, but professionals have access to much more effective cleaning products than you can buy in your local hardware store. They also have experience dealing with moss, stains, and more, so it is usually best to call in a pro.
• Warranty. Before scheduling a roof cleaning, check the details of your warranty. Most of them come with warranties of up to 30 years, and professional cleaning may be covered as a part of the policy.
• Home’s value. A well-cleaned and properly maintained roof can increase your home’s market value.