Roof Cleaning Estimating

Creating an estimate for a roof cleaning project can be challenging but we will break down the process in 4 steps and do an example of a real residential address together. Additionally, you can use our Roof Cleaning Calculator to create your estimates while you are developing pricing that fits your market.

Step 1 - Determine Flat Square Footage

The first step in determining an estimate for a roof cleaning is to measure the flat square footage of the roof that needs to be cleaned. This can be accomplished by manually measuring the perimeter of the roofline with a Measuring Wheel, estimating the size by looking at it or using online tools like roofr. Google Earth offers a free measuring tool to help you with most properties. Simply type in your address in the search field. Make sure the map is in 2D mode. When the house comes up, click on the measuring tool on the left-hand side. From there, you can outline the house to get the perimeter and area measurements. The number listed under “Area” will be the roof square if it were flat. 

Step 2 - Determine Roof Pitch

Most roofs have a pitch or an incline to them. This adds more roof square footage to the total roof measurements. There are many ways to determine or estimate the pitch of a roof. First, you can place a Pitch & Slope Locator on the roof to determine the average angle in degrees. Or you can use a digital-level measuring device like the Measuring tool on an iPhone. Lastly, you can estimate the pitch visually or on a 3D view of Google Earth. Once you have the Pitch or Angle, you will find the multiplier in the chart below and times that number by the flat square footage determined in step 1. This will give you an estimated total roof square footage. You can be as detailed as you desire in this step, measuring each pitch variation, or you can get an approximate number. 

Roof Pitches are usually represented in a number over 12 (example: 6/12). This means that for every 12 inches the roof runs from the edge to the center point horizontally, the roof will vertically increase by 6 inches, creating a slope.

Step 3 - Determining Price Based on Square Footage

Most roof cleaning companies charge between $0.30 and $0.50 per square foot. Several factors come into play in that multiplier. The difficulty, amount of moss on the roof, number of stories, and access to parts of the roof are just to name a few. As you gain experience, have a better understanding of your completion times, and have a feel for market rates, you can establish a more concrete base price range for your own company. 

Step 4 - Calculating a Total

Once you've gathered all the necessary information, multiply the total square footage of the roof by the base price. Add any additional costs for ladder rentals, lifts, water trucks, etc. This should give you a profitable estimated cost. 

Let's Do An Example Together

1. Visit Google Earth.
2. In the search bar, type the following address, "3132 Boulevard Rd SE, Olympia, WA 98501"
3. Make sure you are in 2D  or Overhead view. Click on the measuring tool and outline the main building's roof. You should get an area around 10,000 sq ft.
   
   
4. Now enter 3D view by clicking the "3D" button in the bottom right of your screen. By looking at the roof pitch, you can estimate that it is it is a 6/12 or 26.6° pitch. This would give us a multiplier of 1.118.
5. Now we take our square footage 10,053 and multiply it by 1.118 to get an estimated 11,240 actual square footage.
6. A company may have a base rate of $0.30 per square foot for a simple soft wash. We would multiply the base rate times the square footage to get $3,372 as an estimate to soft wash this entire roof.

For reference, use the Roof Cleaning Calculator until you become more proficient.