December 08, 2023

The professional contract cleaners online resource!
Breaking News
Right Side
Left Side
Roof Cleaning Spraying Techniques

Roof Cleaning Spraying Techniques

Read our roof cleaning issues:

By Doug Rucker, Owner of Clean & Green Solutions and Founder of the Pressure Cleaning School,

One of the most important factors in determining how profitable and successful your roof cleaning business will be is your spraying technique, method of application, and amount of mix you apply, along with your pricing, of course. Ask ten different roof cleaning contractors how they spray a roof and you will probably get ten different answers. And none are necessarily more right or wrong than the other. Top to bottom, side to side, from the ladder, from the ground only, one application, two applications, two applications with a spot follow up, and on and on the list goes. Everyone has his or her own method and technique for spraying a roof. All of them work. Because it is the cleaning mix that is doing the work, as long as you’re getting the mix to the roof, and the mix is good, the roof will clean up. But how you spray can and will determine how much mix you use, your amount of runoff, plant damage and how long you will be on the job. For of this article, I am going to talk about how I spray and how I teach students at The Pressure Cleaning School to spray an asphalt shingle roof, which is about 90 percent of the roofs we do. I’ll discuss first how I spray a one-and two-story walkable roof and then a two-story unwalkable roof.

One and Two Story Walkable

For me, the key to applying the mix is to apply thin coats so as just to dampen the shingles. I am not looking to flood the roof with mix, I just want the shingles damp or moist. Whenever I see streams of mix running down I always feel that I am applying too much mix and will try to adjust the amount I am spraying. I realize runoff is inevitable, but large amounts are what I am trying to avoid. My goal is no more than one to 1.5 gallons in my buckets under any downspouts if gutters are present. Step 1: Starting at the gutter line, I will spray out the first three to four shingles up moving horizontally across the roof. I position my body and feet so that I am facing back to the top of the roof as much as I comfortably can.

Step 2: With my gun pointing up toward the top of the roof, I then coat the first three to four shingles, again moving horizontally across the roof. Step 3: Once I have reached the edge, I then will spray – with my body and gun pointing toward the roof and not toward the non-roof area – where grass or plants may be below. Step 4: Moving up to the top the roof, I spray out the edge of the roof, as I did the bottom, three to four shingles in. Step 5: Once the bottom and edge are sprayed, I then spray the rest of the roof, from bottom to top. As I spray, I am applying nice, even, consistent applications. In the first application, I am not looking to add more mix to one spot than another. Once I have sprayed an entire area or section – say the front of the roof – I then go back and hit the really dark areas again, before moving onto another section. Once I have completely applied my first application, I then check the section I sprayed first. If this area is still wet or damp, I will wait until it has dried a little more. Sometimes I will come down and take a break, or if we are doing a house wash as well, I will hand the gun down to my ground man and let him spray out the back and side of the house. The reason I do not spray again if the roof is still pretty damp or wet is because it is a waste of mix. I go by this: “If it’s still wet, it’s still cleaning.” All I am trying to do when I clean a roof is keep it damp. Applying more mix on top of an already damp or wet roof is not going to clean it any better or faster. Once the first coat is nearly dry – I never wait for it to completely dry unless it’s the really hot part of summer – I then apply the second coat, adding just a little more to the dark stains. I spray the second coat the same as I did the first coat. Once the second coat is applied – and this coat usually takes less time to apply than the first – I wait at least 15 to 20 minutes to allow that coat to work. Then any leftover brown stains (dead algae) I hit again quickly so the roof is completely clean. I understand some roof cleaning contractors will explain to the customer that those brown stains will come off with the rain – and they will – but for the money I am charging, I just prefer that the roof be totally clean before I leave. My before and after pictures are better too. You will always have some roofs that will take more time than others. For example, thinner shingles are going to absorb faster than the thicker shingles. I have just found that the key for me is giving a little time between coats instead of continual spraying until the roof comes clean.

Two Story

Spraying a two story house is, of course, totally different than spraying a one story. More often than not, the two story homes around here have very steep and I will not walk them. I am very careful about what I will walk and what I will not. If I have any hesitation about walking a roof, I will not. I will just spray it from the gutter line. Whenever I spray a roof from the gutter line standing on a ladder, I try to copy as best I can the way I spray a one story. Using my zero tip, I will coat the first three to four shingles up to the left and right of me. As the shingles get wet and I get closer to the area where I am standing, I will switch to a fan spray tip, and spray the areas immediately to the left, right and directly in front of me. For the area directly underneath the ladder stabilizer, I can barely pull the trigger on my gun, allowing for only small stream to coat this area. This prevents the mix from splattering onto my face and clothes. I like using a trigger style gun I get from Paul at because it allows me better control and I can stop the flow immediately versus a ball valve. If I drop the gun, I also know that the flow will stop immediately versus not being able to turn off the ball valve. Once I have coated all the areas to the left and right, I then start spraying from the bottom up using my fan tips or the zero tip depending on the distance I need. This spraying technique requires changing the tips somewhat frequently. I realize I could use the zero tip and probably spray it out much faster, but that would also require using a lot more mix. Also when I see the mix really start to flow down the roof, I will stop spraying for a few seconds to allow it to soak in. So, there is some starting and stopping with this technique. This is another reason I find the trigger gun so much more convenient than a ball valve. Once I have sprayed that section out completely, I will then come down and either spray out another section of the roof, clean a section of the house if that is part of the job, or just take a break. In any event, I allow my first application to sit at least 15 to 20 minutes before I will spray it again. The second application is done the same as the first and then the third is done just hitting any spots that may need it. Often I will come across a two-story roof that is walkable, and if so, I will spray it just like I do a one-story roof. Often, a two story unwalkable roof will still have a “route” I can take and get to the peak, the ridge line, and I can spray everything from there. When doing this, I use the zero tip for 90 percent of the application. BUT I will start spraying at the bottom and spray up towards me, stopping and starting as needed to control runoff. There is just something about new mix hitting the already applied mix that seems to help control runoff. Again, I realize that everybody has different ways to spray out a roof and I certainly do not advocate that there is one set way. Each individual will adapt his or her own methods and system; this is just the way I prefer to do it. I realize that it may seem to take more time, and I am OK with that. The last thing I want to hear my customer say when I am done is, “You’re done already?” Hopefully some of the new (and old) roof cleaning contractors can pick up something here that will help them make there business better. No matter how you decide to spray a roof, two things are essential to your roof cleaning business: 1. Develop systems and procedures so that you are efficient from the time you pull up to the time you leave 2. Develop a consistent spray pattern. This will help to prevent you from missing some areas and applying to much in others. It doesn’t matter as much the pattern you develop, just develop one and be consistent. Doug Rucker is the owner of Clean and Green Solutions in Kingwood, Texas, and Vice- President of the United Association of Mobile Cleaning Contractors (UAMCC). Because he enjoys helping, teaching and mentoring those who are new to the pressure washing industry, Doug started the Pressure Cleaning School in 2011 where he provides both class training as well as one-on-one instruction. To learn more, visit the school’s website at

Subscribe to our mailing list

Powered by Robly

Related posts