If you’re in the pressure washing or exterior cleaning industry, you’ve likely encountered terms like SH, chlorine, bleach, and sodium hypochlorite. To an outsider—or even someone new to the field—these terms can seem confusing, even interchangeable at times. But understanding the differences and proper usage is essential for achieving the best cleaning results while staying safe and compliant.

What Do All These Terms Mean?

• Sodium Hypochlorite (SH): Sodium hypochlorite, often abbreviated as SH, is the chemical name for the active ingredient found in household bleach and many commercial cleaning solutions. In pressure washing, SH is widely used for its ability to kill mold, mildew, and algae, as well as for its bleaching and disinfecting properties. It’s typically available in different concentrations depending on the application.
• Chlorine: Technically speaking, chlorine is a chemical element (Cl) that is used in various forms, including as a disinfectant. However, when people in the cleaning industry refer to "chlorine," they are often talking about sodium hypochlorite in liquid form. Confusion arises because sodium hypochlorite solutions contain chlorine in the form of hypochlorous acid, but they are not pure chlorine gas.
• Bleach: Bleach is a term we all know from household use, but it's often misused in the industry. Essentially, bleach is just a diluted solution of sodium hypochlorite, usually around 5-6% concentration in household products. Commercial-grade bleach, like what’s used in pressure washing, is stronger, typically ranging from 10-12.5% SH, which is necessary for effective exterior cleaning on surfaces like siding, roofs, and concrete.

Why the Confusion?

The confusion stems largely from how these terms are used interchangeably in everyday conversation. People will often say "bleach" when they’re actually referring to higher-concentration sodium hypochlorite. Similarly, "chlorine" gets thrown into the mix, even though it's the active component within sodium hypochlorite rather than something used independently in this context.

Think of it this way:

• Chlorine is the element,
• Sodium Hypochlorite is the chemical compound we use in cleaning,
• Bleach is a solution that contains sodium hypochlorite.

SH in Exterior Cleaning

In pressure washing, SH is used for soft washing techniques where lower pressure is combined with a chemical mix to safely clean surfaces like roofs, siding, and driveways. The percentage of SH you need depends on the job:

• Low concentrations (0.5%-2%): Ideal for house washes or sensitive surfaces like painted wood.
• Medium concentrations (2%-4%): Best for tougher stains or algae/mildew removal on concrete or stone.
• High concentrations (4%-6%): Useful for roof cleaning and surfaces where organic growth is more deeply embedded.

How to Calculate Your SH % Concentration

One of the most important things when working with sodium hypochlorite is knowing the percentage concentration you're applying to a surface. If you're diluting SH from a stronger concentrate (like 12.5%), you can figure out your final concentration using a simple formula:

\frac{(\text{Concentrated SH %}) \times (\text{Amount of SH added})}{\text{Total solution volume}} = \text{Final % Concentration}

For example, if you’re using a 12.5% SH and you mix 1 gallon of SH with 4 gallons of water (totaling 5 gallons of solution), the formula would look like this:

$\frac{12.5\%\times 1}{5}=2.5\%$

512.5%×1=2.5%

This means your final mix has a 2.5% sodium hypochlorite concentration, which would be suitable for a house wash. If you need a lower concentration, simply add more water.

Don’t Forget the Surfactant: Adding Elemonator

To make your cleaning solution even more effective, you’ll want to add a surfactant like Elemonator, which helps the solution stick to surfaces, breaks down grime, and improves rinsing. The recommended amount is 1 ounce of Elemonator per gallon of solution.

In the example above, since you have 5 gallons of total solution (1 gallon SH + 4 gallons water), you would add 5 ounces of Elemonator. This ensures the solution clings to the surface longer, allowing the SH to do its job more effectively without running off too quickly.

Adding a surfactant is especially helpful when dealing with vertical surfaces like siding or roofs, as it prevents the solution from dripping off before it has time to break down the organic matter you're cleaning.

Common Concentration Ratios for Pressure Washing:

• House wash: Typically 0.5-2.5% SH
• Concrete cleaning: Around 3-4% SH
• Roof cleaning: Often 4-6% SH depending on the severity of mold, mildew, or algae

By calculating your SH percentage properly, you ensure you're using the correct concentration for the task at hand without wasting product or risking surface damage.

Safety and Handling

Understanding the strength of SH you’re working with is crucial for both safety and effectiveness. Too strong, and you risk damaging surfaces or harming nearby plants. Too weak, and you won't get the desired cleaning results. Additionally, proper PPE (personal protective equipment) should always be worn when handling SH, as it can cause irritation or burns on skin and eyes, especially in higher concentrations.

Final Thoughts

While SH, chlorine, bleach, and sodium hypochlorite might sound confusing, the key takeaway is that these terms are often referring to the same cleaning agent in different forms and concentrations. In the world of exterior cleaning, SH reigns supreme due to its versatility and power in combating mold, algae, and grime. Understanding the distinctions between these terms and how to properly use SH, including calculating your concentrations and adding surfactants like Elemonator, is crucial for anyone involved in pressure washing.