Difference Between Water Blasting and Soft Washing / Chemical House Washing
Many homeowners assume water blasting and soft washing achieve the same result, but that’s not always the case. While both methods are used to clean exterior surfaces, choosing the wrong approach can damage paintwork, force water behind cladding, and shorten the lifespan of your home’s exterior. At NZTS, we’ve worked with a wide range of properties and seen firsthand how the right cleaning method can make all the difference. Understanding the strengths and limitations of each approach is the first step towards achieving a cleaner, longer-lasting result.
What Is Soft Washing?
Soft washing is a low-pressure cleaning method that uses specialised cleaning solutions to remove mould, algae, dirt, and other organic growth from exterior surfaces. It is commonly used on painted weatherboards, cladding, roofs, and other delicate areas where high pressure could cause damage.
What Is Water Blasting?
Water blasting uses high-pressure water to remove dirt, grime, moss, and stains from hard surfaces. It is best suited for durable areas such as concrete driveways, paths, patios, and retaining walls, where a more powerful cleaning method is needed.
What’s the difference between soft washing a house and water blasting a house?
The biggest difference between soft washing and water blasting is the cleaning method itself. Soft washing relies on specialised cleaning solutions and low pressure to break down mould, dirt, and organic growth, while water blasting uses high-pressure water to remove surface contaminants.
Water blasting can be effective for hard surfaces, but it will not always achieve the same results as a chemical house wash. Mould and organic growth often require more than water pressure alone to be properly treated. Think of it like washing a greasy frying pan with only cold water; it may remove some dirt, but without a cleaning solution, it’s difficult to achieve a thorough clean.
Potential Risks to Consider
Both soft washing and water blasting can cause damage when used incorrectly. Soft washing requires the correct chemical mix and application, while excessive water pressure can damage paintwork, timber, and cladding. That’s why it’s important to choose an experienced operator who understands which cleaning method is best suited to your property.
Water Blasting and Damage
Water blasting has the potential to cause around the home by forcing water in behind cladding and into cavities around the house. One of the problems with water blasting is that the damage often isn’t visible until after the surface has dried. At this point marks and damage on the house are too engrained to repair easily.
Why is it important to understand the mix rates when chemical washing a house?
Soft washing a house with the correct amount of chemical and soap means that more of the cleaning reaction taking place happens on the dirt and mould on the house and not in the garden and in the rest of the environment.
The truth about “biodegradable” in the house washing industry.
You will often see house washing companies claim biodegradable products. This is true to some degree but unfortunately, these biodegradable chemical house washing products aren’t environmentally friendly. The chemical the industry is talking about is a pool bleach. It does biodegrade in sunlight and heat but can be potentially dangerous at higher strengths. Although house wash chemicals are biodegradable, if it is used at strength strong enough to burn organic matter this will create non-biodegradable by-products from the reaction. These free radical particles build up in the atmosphere, ecosystems and in our bodies.
A good house washer should understand the sort of mould they are washing and how strong the chemical house wash mix needs to be.
How often should a house be washed?
A house should be washed annually. Having it done regularly will ensure less pressure and less chemicals needs to be used to get the house sparkling clean again. Even when the house looks clean it will still be accumulating dust and organic matter that isn’t visible. Once this organic matter builds up it gives mould a place to grow and will quickly turn to more damaging types of mould like red mould and lichen.
When is a house beyond a soft wash?
A house is beyond soft washing when you start to see lichen growth. At this point the lichen must be removed by applying hard pressure usually through a water blaster or brush. There will always be some level of damage to the house once lichen grows. This is a big sign that you are well over due for a house wash!
Thanks for reading and as always feel free to contact us for any further information.
0800 777 296
