• What affects roof cleaning costs?
• Average roof cleaning costs
• How to save money on roof cleaning
• How to hire roof cleaners
• Benefits of professional roof cleaning

The factors that affect your cleaning cost include square footage, time (if ever) since your last cleaning, the type of roof cleaning you need, and roof height and pitch. Most roof cleaners will want to see the roof before providing their free estimate to more accurately understand the job. Generally speaking, the more difficult it is for a professional to get a roof clean, the more it will cost.

Roof size

The size of roof usually directly correlates to how long it will take to clean and, thus, how much it will cost to clean. The larger the roof, the higher the price. Many roof cleaners charge by the square foot, and others charge by the square—a roofing term—which is equal to 100 square feet. In one example, if a home is 3,000 square feet, and the average cost of roof cleaning is $350, the approximate cost per square foot would be 12 cents.

Time since last cleaning

The longer it’s been since a roof was last cleaned or the dirtier it is (for any reason), the longer it will take to clean. The overall cost is likely to be higher. As an example, homes in areas that are exposed to seawater, continuous rain, or high humidity often have higher cleaning rates than homes in moderate climates, because the associated salt, algae, and mold require added care and attention.

Type of cleaning

The type of roof you have can determine the type of cleaning used. Asphalt shingle, ceramic tile, clay tile, concrete tile, slate, tar and gravel, and wood all require different cleaning methods. Be wary of roof cleaning services that use harsh chemicals, because they can erode the integrity of your roof shingles. You should also be very wary of a company using full force (3,000 psi) power washing equipment. The intense pressure can dislodge roofing materials. Not surprisingly, the more complex tne roof is, the longer it will take to clean and the higher the cost. For example, roofs with hip sections—slopes on all four sides—and those with obstructions such as chimneys, trees and decks will cost more to clean. Chemical soft washing (low pressure water washing mixed the appropriate cleaner) and low pressure washing are two of the most common methods of roof cleaning. Hand washing with a hose and nylon brush may also be appropriate depending on your roof’s needs.

Pitch or slope

Roofs with steeper slopes are more dangerous for the cleaners, so safety precautions and staging may have to be added. These conditions will increase labor and overall costs.

Location

The roofs of homes at the beach or in the mountains are affected by weather and atmosphere and can be more dirty than in other areas. Roof cleaners may charge more because it will take longer to clean a roof in these locations. If there’s a lot of salt, moss or algae on a roof, the price will be higher for cleaning because those substances are more stubborn to remove. Additionally, your zip code will impact local costs for labor and your roof cleaning.

Height

The more stories a home has, the more difficult it is for cleaners to maneuver their personnel and equipment to clean a roof effectively. Safety is a concern and reputable companies will require their workers to use harnesses for higher heights. Due to the added precautions necessary, the taller your building, the more expensive your roof cleaning services can be.

Nationally, $350 is the average cost for professional roof cleaning. This includes removal of visible and unseen organic growth (such as lichen and algae) from shingles using the appropriate cleaning method for your roof material, as well as removal of storm detritus and fallen leaves. Upon request, many cleaners can apply zinc strips or anti-growth sprays to protect a roof until the next cleaning. These services cost extra. Most cleaners charge under $50 per zinc strip plus installation, for example. Three Thumbtack Pros cited their average job costs for Thumbtack customers as following:

• $100-$300, depending on square footage and roof materials
• $200-$300, depending on square footage and roof materials
• $225-$600, depending on square footage and roof materials

Some roof cleaning companies offer discounts if customers get on a regular cleaning schedule, such as once or twice a year. Some roof cleaning companies also offer to clean gutters, so you may be able to get a discount if you combine the two services. A DIY cleaning solution is not recommended unless you have the proper safety equipment and cleaner for your roof surface. If you plan on DIY power washing, proceed with caution. DIY pressure cleaning can do more harm than good, potentially causing damage to tiles, shingles or shingle granules. Even if you are qualified to use a pressure washer, make sure your roof warranty doesn't require that you use a professional roof cleaning service or risk voiding of the warranty.

When hiring a roof cleaning company, always read online reviews and look for positive customer service. Due to the liability involved, hire a company that has the appropriate insurance and provides workers compensation for their employees. Insurance and workers comp keep everyone safe in case of a roof slipping accident. Always ask what roof cleaning methods the company will use on your roof, and verify they will not use high-power pressure washing equipment that can damage your shingles or tiles.