House Washing

How soft wash chemistry works

The active ingredient in our soft-wash solution is sodium hypochlorite. It is the same compound in domestic bleach but diluted to a safe working concentration, usually around 1 to 4 percent depending on the surface and the contamination load. We pair it with a biodegradable surfactant that helps the solution cling to vertical surfaces long enough to penetrate mould hyphae and algae cell walls. The chemistry kills the organic material at the source, which is the part that high pressure alone cannot do. High pressure removes visible surface contamination but leaves spores and root structures intact, so the mould returns within months. Soft wash dwells for ten to twenty minutes before being rinsed off, and the result is a wall that stays clean for 12 to 18 months in Brisbane's climate.

PSI ranges by surface

Pressure on wall surfaces in a soft wash is around 100 to 500 PSI, well below the threshold that would lift sound paint or force water under cladding. High-pressure work on hardscape runs 2,500 to 4,000 PSI through a surface cleaner attachment, which gives even passes and a streak-free result. Render and weatherboard cap at the low end of the soft-wash range. Painted brick and unsealed brick handle the middle of the range. Concrete tile or Colorbond walls (less common in Brisbane homes) sit at the upper end of soft wash but never high pressure. We adjust the pressure on each surface as we work. There is no single setting for an entire house.

Render, brick, weatherboard: surface-by-surface

Render is the most common Brisbane wall surface and the most variable. Acrylic render, sand-and-cement render, and textured render all hold mould differently. Textured surfaces hold the most because there is more cavity for spores. Render gets the lowest pressure end and the longest chemistry dwell. Painted brick handles slightly more pressure but the chemistry does the lifting; we avoid high pressure on mortar joints because hairline cracks can let water through. Unsealed brick is rare on Brisbane homes but tolerates more pressure. Weatherboard is mostly painted timber, including chamferboard, traditional weatherboard, and modern composite weatherboard like Linea, and each wants a different technique. The common rule on weatherboard is to never spray upward into the board overlap because water can drive behind the boards. We always work top-down on weatherboard. Fibre cement sheeting (HardiePlank, modern fibre cement panels) cleans similarly to render. Older fibre cement that may contain asbestos is handled with the lowest possible pressure and minimal physical contact: soft wash chemistry only, no abrasion.

Our process, step by step

Step one: pre-wet plants, beds, and any sensitive surfaces around the home. Step two: apply soft-wash solution from the bottom up on each wall section. This prevents streaking and lets gravity work with us rather than against us. Step three: dwell for ten to twenty minutes depending on contamination load and weather. Step four: rinse from the top down at low pressure, working in shaded sections so the surface stays wet until the rinse reaches it. Step five: move to the next section. Step six: walk the property with you, confirm the result, and send before-and-after photos by SMS or email. Most single-storey homes finish in two to four hours. Double-storey homes take four to six hours. Detail-heavy heritage homes can run a full day.

What to expect on the day

We arrive in the window agreed (most jobs start between 7:00 and 8:30am to make the most of the day). The first 15 to 20 minutes is setup: running the hose to your tap, plugging the pressure washer into a power point, walking the property to confirm scope, and pre-wetting plants. The clean itself is the next two to four hours depending on size. During the wash you can be home or out. As long as windows and external doors are closed, you can carry on as normal. We let you know when we're rinsing each section so you can avoid that side of the house if you want. Once the final rinse is done we walk the property with you (or solo), check anything you point out, and send photos. The whole visit is usually wrapped by mid-afternoon. The walls dry within two to four hours and there is no residue left on glass or doors.

Surfaces we clean (and what we exclude)

We wash render, brick (painted and unsealed), weatherboard, chamferboard, Colorbond cladding, fibre cement sheeting, painted timber detail, fascia, eaves, gutters (external surfaces), and window frames. We exclude any surface that the customer specifically asks us not to touch, any surface where the existing finish is failing badly enough that cleaning risks lifting it, and unsealed asbestos sheeting where we cannot confirm the condition. If we identify a concern during the pre-clean walk-around, we will tell you before starting and discuss whether the job can proceed safely.

Common Brisbane situations and how we handle them

Heavy shade mould: a south-facing wall under a fig or jacaranda is the most common Brisbane scenario. The chemistry dwells longer (closer to twenty minutes), and we sometimes do a two-pass treatment where the first pass kills the mould and the second pass removes the residue. Bayside salt algae: Wynnum, Manly, Redland Bay, Ormiston walls develop a particular salt-driven algae that responds to a slightly higher chemistry concentration. Pre-paint clean: washing the day or two before a painter starts is one of the most efficient ways to prepare a surface. We coordinate timing with the painter so the surface is dry but freshly clean when they arrive. Insurance and pre-sale cleans: these jobs come with a higher photo-documentation requirement, which we handle as standard. Chalky paint: older paint can be slightly powdery, which means the chemistry will lift some surface paint along with the mould. We test a section first and tell you what to expect; sometimes a wash is a useful first step before a repaint, sometimes it surfaces a paint issue that was hidden.

Why Brisbane homes need washing every 12 to 18 months

Brisbane's subtropical climate is the fastest mould-growth environment in Australia outside the tropical Far North. Humidity sits at 60 to 80 percent for most of the year, the average temperature rarely drops below 12 degrees overnight, and rainfall in summer keeps surfaces damp for extended periods. Mould and algae only need 24 hours of consistent moisture and warmth to start a colony, and once established they grow exponentially. A wall that looks fine in winter can develop visible mould banding by autumn the following year. The 12 to 18 month wash cadence is what keeps surfaces ahead of the growth cycle. Bayside suburbs (Wynnum, Manly, Redland Bay) typically run on a 12-month cadence because salt accelerates the process; inland suburbs with less canopy can stretch to 18 months.

DIY vs professional house washing

A consumer pressure washer from Bunnings runs 1,500 to 2,500 PSI and ships with a fan nozzle that is either too narrow (and will gouge the paint) or too wide (and will not clean effectively). It can rinse loose surface grime but cannot kill the mould at the source. Within months the mould returns because the spores were never treated. Professional soft wash uses the chemistry to kill what the rinse then removes, which is the meaningful difference. The other DIY pitfall is ladder work on a two-storey home: most home falls happen on ladders at this height, and the additional risk of working with chemicals and water on a ladder is not trivial. For a single-storey home with light dirt and no mould, DIY is fine. For anything with set-in mould, two-storey access, render, painted timber, or insurance/pre-sale stakes, professional soft wash is the correct call.

What sets owner-operated work apart

Every Proper Pressure job is completed by the owner directly, not a subcontractor or a casual employee on a per-job rate. That matters for a few practical reasons. The quote is the result, because the person quoting is the person doing the work. Technique is consistent across every job rather than varying with whoever turned up. And accountability is direct: if anything needs follow-up, there is one person to call. The trade-off is that we are not the highest-volume operator in Brisbane, so booking lead times can be one to two weeks for non-urgent work. For most customers, the trade-off is worth it.

What's included

• Safe soft-wash technique with no high-pressure damage to walls
• Works on render, brick, weatherboard, fibre cement, and cladding
• Removes mould, algae, dirt, cobwebs, and atmospheric grime
• Includes eaves, fascia, and external wall surfaces in standard quote
• Biodegradable cleaning solutions, pre-wet plant protection
• Before-and-after photos with every job
• Same-day fixed quotes, owner-operated, fully insured

House Washing by suburb

Detailed house washing guidance for the suburbs we work in most often. Each page covers local housing stock, common concerns, and pricing notes specific to that area.

Frequently asked questions