Water Blasting – Will It Damage My House

If the operator is not skilled and trained, then yes. Cedar is the building material in the photo. Many house-washing companies won’t even try water blasting Cedar.

AWL has successfully restored nearly 300 Cedar-clad properties around Auckland and the North Shore over the past ten year. Each property is meticulously restored until it looks almost like new. Many clients say that their homes feel almost brand new.

Water blasting – What are the Risks?

Untrained people using water blasting to clean exteriors of buildings are causing more concern.

Water blasting equipment was once only available to professionals, but they are now available to everyone. A machine can be purchased at your local hardware store or rented.

Exterior wall cladding should be cleaned and maintained regularly to preserve their beauty and extend the life span.

Many building materials are not built to withstand water pressures created by the majority of the “off-the-shelf” water blasting equipment.

New Zealand homes must be able to withstand pressures of 1.5 to 2.5 kPa. This is equivalent to an average wind gust at 180 km/hr.

Many domestic water blasting machines can only withstand pressures of 1500-1885 psi. This is combined with the 8300 kpa standard nozzle that comes with the machine, and it can have a devastating impact on walls and joints.

These pressures are not suitable for standard building materials, joints, and seals. House Water Blasting in Auckland is possible without the right equipment and training.

  • Weatherboards damaged by soft winds
  • Remove mortar from brick joints
  • Blot off any paint film on the cladding edges
  • Use dislodge sealant to waterproof
  • Force water into joints and wall cavities …. And
  • You can also erode the protective paint layer.

Water blasting equipment should never be used inadvertently

Water blasting can cause damage to your home if used in an indiscriminate manner. You may not have the right training for the surface you want to clean.

You may need to use water blasters on specific materials in certain situations.

You can clean your house with a soft brush or a garden hose if you prefer to do it yourself.

Here are some simple rules to ensure water blasting safety

These simple rules will help you reduce the chance of damaging joints and cladding by water blasting.

  • Before you do anything, make sure to read the operating instructions.
  • Be familiar with all safety regulations.
  • Make sure to check the warranty and maintenance specifications provided by roofing and cladding companies. Incorrect use of roofing or cladding can cause warranties to be voided.
  • Use the lowest pressure setting.
  • The nozzle should be set to ‘wide spray’, and kept at least 500mm from the building’s surface.
  • To get rid of stubborn dirt, don’t hold the nozzle too close to a surface. Instead, use a brush or mop.
  • Do not point the nozzle at joints or aluminum joinery. Sealants are essential for weather resistance and can be damaged by high pressures.
  • Only use cold water and lite detergents


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