What soft washing is
Soft washing uses low pressure, about the force of a garden hose, to apply a cleaning solution to a surface, let it work, and rinse it off. The chemistry does the cleaning, not the force. The solution kills the mould, algae, lichen and moss that make a house look dirty, and because it kills the growth at the root rather than scraping the top off, the surface stays cleaner for much longer.
It is the right method for almost everything above the ground: painted walls, render, weatherboard, fibre cement, brick and mortar, Colorbond and metal cladding, eaves, gutters, fascias, tiled and metal roofs, pergolas, fences and timber screens. Anything with a paint film, a coating, a texture or a joint in it.
What pressure washing is
Pressure washing (pressure cleaning, high pressure cleaning, water blasting) uses water at high pressure to physically blast dirt off a surface. Done properly, with a surface cleaner rather than a bare wand and a pre-treatment that breaks the growth down first, it is the right method for hard, flat, unpainted surfaces: concrete driveways, paths, exposed aggregate, pavers, pool surrounds and sandstone.
On those surfaces the force is useful, because the grime is ground into a hard material that will not be damaged. On a house wall, the same force is destructive.
What high pressure does to a house
- Paint and render. High pressure lifts paint at any weak point and leaves a wall that looks worse than when it started, with clean stripes and bare patches. On render it blows out the texture and opens hairline cracks.
- Weatherboard and fibre cement. The water is forced up under the laps and behind the boards, into the wall cavity, where it sits.
- Brick and mortar. Mortar is softer than brick. High pressure pits it and blows sand out of the joints, and the face of soft or old bricks can be cut.
- Windows and seals. Pressure finds its way past rubber seals, flyscreens and weep holes.
- Roofs. High pressure strips the surface coating off concrete and terracotta tiles, forces water under the laps, and shortens the life of the roof. It also does nothing to the roots of moss and lichen, which grow straight back.
Most of the damage people blame on "the house wash" is high pressure used where it should never have been.
Why the chemistry matters more than the force
Mould, algae and lichen are living things. Blasting them off leaves the roots behind, and the wall greens up again within a season. A soft wash solution applied at the right dilution for the surface kills the growth, which is why a properly soft washed house stays clean far longer than a pressure washed one. It is also why Dript can offer a 12 month regrowth warranty on house and roof washing: if the growth comes back within a year, we return and treat it again at no cost.
The right dilution is the skill. Too weak and the growth survives; too strong and plants, pets and finishes are at risk. We rinse all vegetation before, during and after a wash, use tarps where needed, and ask that pets stay indoors while we are working. Once we are done, everything is safe.
Which does your home need?
Almost every home needs both, in different places. The walls, eaves, roof, fences and anything painted need a soft wash. The driveway, paths, patio and pool surround need a pressure clean. A good exterior cleaner will walk the property, name the method for each surface, and quote them together. If someone offers to "pressure wash the house", ask what pressure they intend to use on the walls. The answer should be low.
How Dript does it
Every surface is cleaned with the method that suits it: soft washing for walls, roofs and delicate surfaces, and controlled pressure only where a surface can take it. Before we start we assess the property, bag and tape the electrics, cover what needs covering and protect the garden. Every house wash includes a free exterior window clean with purified water, and every clean comes with a report of before and after photos.