Melbourne’s cool, damp winters and poorly ventilated buildings make mould one of the most common hygiene complaints in Victorian workplaces. Search interest in mould across Victoria peaks every winter and stays high well into spring, and for good reason: black spotting on washroom grout, musty storerooms and grey bloom behind furniture are signs of a moisture problem that will keep getting worse until it is dealt with. Effective mould removal in a commercial building means fixing the moisture source, cleaning with the right product and protecting the people doing the work.
For most hard, non-porous surfaces, a commercial chlorinated cleaner and sanitiser such as Agar Chloradet removes surface mould staining and sanitises in one step. This guide explains when that approach works, when it does not, and how to keep mould from returning.
Why Mould Grows in Commercial Buildings
Mould spores are present in almost all indoor air. They only become a visible problem when they land on a surface with enough moisture and organic material to feed on. In commercial buildings the usual causes are:
- Condensation: warm, moist air meeting cold glass, walls or ceilings, especially in winter when heaters run and windows stay closed.
- Poor ventilation: washrooms, change rooms and kitchens with undersized or blocked exhaust fans.
- Water leaks: roof leaks, failed shower seals, leaking pipes inside walls and air-conditioning condensate drains.
- Soft furnishings and stored stock: carpet, cardboard and fabric that stay damp after a spill or flood.
Until the moisture source is controlled, any mould removal work is temporary. Cleaning treats the symptom; ventilation and repairs treat the cause.
Health and Safety: Why Mould Matters at Work
Mould can trigger allergic reactions, irritate the eyes, skin and airways and worsen asthma. Victoria’s Better Health Channel explains the health effects of mould exposure and why people with asthma or weakened immune systems are at higher risk. Under WHS laws, employers must provide a workplace without risks to health so far as reasonably practicable, which includes addressing damp and mould once it is identified.
Assess Before You Clean
Before starting any mould removal job, decide whether it is a cleaning task or a remediation project:
- Small, surface-level growth on tiles, grout, glass, sealed timber, metal or painted surfaces can usually be cleaned by trained cleaning staff.
- Porous materials such as plasterboard, ceiling tiles, carpet underlay and insulation that are heavily affected usually need to be removed and replaced, not cleaned.
- Large areas (roughly more than a square metre), mould inside wall cavities or HVAC ducts, or growth following flooding or sewage should be handled by a qualified mould remediation specialist.
Step-by-Step Mould Removal on Hard Surfaces
- Protect the cleaner. Wear nitrile gloves, eye protection and a P2 respirator. Disposable coveralls are sensible for larger jobs.
- Ventilate. Open windows and run exhaust fans. Close doors to occupied areas so spores are not spread.
- Do not dry brush. Dry scrubbing or dusting releases spores into the air. Lightly mist the area first.
- Clean off the growth. Apply a detergent or mould cleaner, agitate with a soft brush or colour-coded cloth and wipe away the visible growth.
- Treat the surface. Apply a chlorinated cleaner or suitable disinfectant, observe the stated contact time and rinse if the label requires.
- Dry thoroughly. Use fans or dehumidifiers. Surfaces left damp will regrow within days.
- Dispose of materials. Bag used cloths, mop heads and PPE and dispose of them; do not reuse cloths from mould jobs elsewhere.
Choosing the Right Mould Cleaner for Commercial Mould Removal
No single product suits every surface. Match the chemistry to the material:
- Chlorinated cleaners (sodium hypochlorite based): fast at removing black staining from grout, tiles and non-porous surfaces. Not suitable for coloured fabrics, some metals or natural stone, and must never be mixed with acids or ammonia.
- Quaternary ammonium disinfectants: odour-free, gentler on many surfaces and useful for ongoing preventive wiping in damp areas.
- Chlorinated cream cleaners: the mild abrasive helps on shower bases, sealant lines and textured surfaces.
- Neutral detergents: suitable for the initial wash on painted walls and sensitive surfaces before a disinfectant step.
Always read the safety data sheet and label. Safe Work Australia’s guidance on managing hazardous chemicals sets out the duties for storing, labelling and using products such as hypochlorite safely.
Mould Hotspots in Commercial Sites
Washrooms and Change Rooms
Grout, silicone sealant, ceilings above showers and exhaust fan covers are the classic mould zones. Weekly scrubbing of grout and daily squeegeeing of shower screens reduce moisture dramatically.
Commercial Kitchens
Coolroom seals, the undersides of benches, dishwasher surrounds and ceiling areas above steam sources need regular inspection. Use food-safe sanitisers on food contact surfaces.
Offices and Storerooms
Look behind filing cabinets on external walls, around window frames, on stored cardboard and inside air-conditioning grilles.
Preventing Mould From Coming Back
Prevention is cheaper than repeated mould removal. Keep indoor humidity below about 60 per cent where possible, service exhaust fans, fix leaks quickly and avoid storing cardboard directly against external walls. Build mould checks into your routine inspections and pair them with regular disinfection of high-risk areas. Our guide to commercial disinfectants and sanitisers explains contact times, chemistry and dilution so preventive cleaning actually works.
Mould Removal Checklist for Facility Managers
Use this quick checklist to keep mould removal consistent across multiple sites or shifts:
- Record where mould was found, the size of the area and the likely moisture source.
- Report leaks, blocked exhaust fans and condensation problems to maintenance on the same day.
- Keep a dedicated mould kit: P2 masks, nitrile gloves, goggles, spray bottles, colour-coded cloths and bin bags.
- Label decanted products correctly and keep the SDS for each mould cleaner in the chemical register.
- Re-inspect treated areas after one and four weeks; regrowth means the moisture problem has not been solved.
- Train staff never to mix chlorine products with acid descalers or ammonia-based cleaners.
Frequently Asked Questions
Does bleach kill mould?
Chlorine bleach removes surface staining and kills mould on hard, non-porous surfaces. It does not penetrate porous materials like plasterboard or timber well, so heavily affected porous items usually need replacing.
Can cleaners do mould removal, or do we need a specialist?
Trained cleaners can handle small areas of surface mould on hard surfaces. Large areas, hidden mould, water-damaged building materials or mould in HVAC systems should be assessed by a remediation specialist.
How often should mould-prone areas be treated?
Washrooms and change rooms typically need weekly treatment of grout and sealant, with daily drying of wet surfaces. Increase frequency during Melbourne’s wetter months.
Keep Your Building Dry, Clean and Healthy
Successful commercial mould removal combines moisture control, the right chemistry and safe work practices. Fix the cause, clean small outbreaks promptly with an appropriate mould cleaner and schedule prevention into your cleaning program. For advice on the right product for a particular surface, contact the Nova Supply team in Melbourne.