What is Soft Washing?

Many of us have already heard of pressure washing. Pressure Washing is the act of using a engine and pump to compress flowing water to a fine point in order to clean or strip a surface. While this is a remarkable process for hard surfaces like concrete and brick, it will cause permanent damage to weaker surfaces like your home siding, roof, or wooden deck.

Soft washing is a relatively new technique that is being embraced by industry professionals everywhere. This is when you use a pressure washing machine or some other water delivery method to spray a treatment comprised of water, sodium hypochlorite and a surfactant on a surface at lower pressure. The goal of this process is to allow the chemical to do most of the work cleaning and disinfecting the surfaces in which it was applied. Then once the treatment has dwelled long enough, it is thoroughly rinsed off. 

What Chemicals Are Used?

The main chemical used in the soft wash process is Sodium Hypochlorite. SH, for short, is the active ingredient in bleach. Professional exterior cleaning specialist typically use a diluted commercial-grade strength (12.5%). Application strength tends to be between 1% for vinyl siding, up to 4-5% for asphalt roofing. For reference, the laundry bleach used in the typical household contains 6% sodium hypochlorite.

The second chemical used in addition to the Sodium Hypochlorite is a surfactant. A surfactant or soap is a substance which is designed allow the SH to linger longer on the applied surface. This is important to help the treatment dwell and clean the surface as much as possible.

What machine can soft wash?

There are three major categories of soft washing equipment. Professional exterior cleaning companies may either use a pressure washer, a 12 volt pump system, or an air pump system. All are equipped with special nozzles that have larger orifices, allowing more water and treatment flow and dramatically decreasing the amount of pressure per square inch (PSI).

Pressure washers require either a downstream chemical injector to add the treatment to the water after the pump but before the hose or they can use a special tip that injects the chemical at the end of the wand. The downstream method is typically found on set ups that are more stationary while the special tip requires a small amount of treatment remains near the wand at all times.

12 Volt Pump systems create usually 60-120 psi and will pump 5-7 gallons of water per minute. Professionals either have the option to create a batch of treatment that contains the Sodium Hypochlorite, Surfactant and Water or they may keep each ingredient separate and use a blend manifold to adjust the mixture in real time. The first method, typically referred to as "Batch Mixing" allows the operator to quickly get started and limits them to having to carry one tank of liquid. The downsides are that they cannot customize the mix for the application on the jobsite. The second method, typically referred to as "Blend Mixing" gives the operator complete control over the treatment mixture at the job site. This is important because different surfaces require different dilution strengths. The downside of this method is that it is costly to set up and requires a vehicle with enough space and is dedicated to the business as this setup is not easily removed.

Is Soft Washing Safe?

Sodium Hypochlorite is a corrosive chemical that is to be handled safely, especially at full 12.5% strength. It can cause chemical burns if it remains on the skin for too long. If SH does get onto your skin or eyes, immediately begin to rinse the affected area for no less than 5 minutes. Full strength Sodium Hypochlorite should only be handled by professionals and it's dangers should be considered seriously.

With that said, Sodium Hypochlorite is the best treatment for the organic growth that builds on home sidings, concrete, and roofs. When applied in the right dilutions, the chemical posses little risk as long as the areas are thoroughly rinsed. As stated, this chemical kills organic life and can be a nuisance to plants and grass if unmanaged. Before applying a Sodium Hypochlorite treatment, create a water barrier around all the surrounding plants and grassy areas by rinsing them with just water. Then, spray the treatment on the areas you'd like to clean. Lastly, rinse off the plants and grass before moving on to ensure no treatment overspray remains.

How long should a soft washed home stay clean?

Soft washing is the best solution for cleaning and disinfecting your property. It not only kills and removes the existing organic matter, but it destroys the growth's food source preventing reappearance for longer. How long your property stays clean depends on a number of factors; how close your home is to tress, types of nearby growth, direction of your property, and more. While there is no definitive amount of time to give, typically you can expect to be growth free for up to two years.

Your Thoughts

We hope this answered your questions about soft washing. Was there anything we missed? Did we help your understanding? Leave a comment below giving us your thoughts.


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