How Many Gallons Of Bleach To Softwash A Roof


How Much Bleach Do I Need to Wash a Roof? Find Out Here!

Hey everyone, Justin here from Forever Self-Employed! Today, we’re tackling a common question: how much bleach do I need to wash a roof? We’ll delve into the details, explore the factors influencing bleach usage, and give you a real-world example to test your knowledge. If you’re serious about mastering roof washing, don’t forget to check out the SESW Softwash 101 Class for comprehensive training.

Factors Influencing Bleach Usage

Before we get into the math, let's talk about the various factors that affect how much bleach you’ll need:

  1. Bleach Strength: Household bleach is about 5%, big box stores offer 10%, and industrial suppliers provide up to 12.5%.
  2. Temperature: Bleach works best between 50° and 70°. Colder temperatures slow down the chemical reaction, requiring more bleach.
  3. Roof Pitch: Walkable roofs allow for even application, using less bleach. Steeper roofs need more bleach due to runoff.
  4. Wind: Wind reduces the amount of solution that sticks to the roof, increasing bleach usage.
  5. Roof Condition: Dirtier roofs need stronger or more frequent applications. The type of buildup (moss, black streaks) also matters.

Real-World Example

Let’s put this into practice. I’ll show you a roof we recently cleaned and let you guess how much bleach we used.

  1. Bleach Strength: We used a 6% solution.
  2. Temperature: Around 85°, no wind.
  3. Roof Condition: Black streaks, no moss.
  4. Equipment: Remco 5.5g 12-volt softwash pump, Batch Buster blend manifold.

Here’s some background: The homeowner had previously hired a painter who used a pressure washer on the roof, causing some damage. We were called to fix it using a soft wash system.

Calculating Bleach Usage

Based on our method, we use approximately 1 gallon of a 6% mix for 50 sq. ft. of roof. This house had 3,680 sq. ft. of roof surface.

  • Total Solution: 59 gallons
  • Bleach Needed: 35 gallons (at 10% strength)

Your Turn

Now, take a guess! How many gallons of bleach did we use for this job? Leave your guess in the comments below.


Understanding bleach usage for roof washing involves more than just simple math. Temperature, roof pitch, wind, and roof condition all play crucial roles. For those looking to deepen their knowledge, the SESW Softwash 101 Class offers detailed training on chemicals, ratios, and techniques to perfect your craft.

Learn More

For those ready to take their pressure washing skills to the next level, check out the SESW Softwash 101 Class. It covers everything from chemical mixes to application methods, ensuring you can handle any job efficiently and effectively.

Thanks for joining me today. If you found this information helpful, hit that thumbs-up button and subscribe for more tips. Until next time, hustle hard and get that money, baby. Peace!

Read more