Mold Mildew - Expert Removal & Treatment Guide
Mold Mildew - Expert Removal & Treatment Guide
What is Mold Mildew?
Mould and mildew are fungal growths that thrive in damp, poorly ventilated environments. In the home, they most commonly appear in bathrooms, basements, and areas with condensation. On stone and tile, mould typically grows in grout lines, silicone joints, and textured surfaces where moisture lingers.
Mould is not just a cosmetic problem - it can cause health issues including respiratory problems, allergies, and aggravation of asthma. It also damages grout and silicone over time, eventually compromising the waterproofing of wet areas.
Effective mould treatment requires both killing the active growth and addressing the underlying moisture/ventilation issue. Without improving ventilation, mould will always return regardless of how well you clean it.
How to Identify It
Mould appears as black, dark green, or dark grey spots, typically in grout lines, corners, and silicone joints. It has a musty smell. Surface mould wipes off with a cloth (leaving a stain underneath). If dark spots do not wipe off, they may be deeply embedded in the grout. Do not confuse with mineral deposits (which are white) or soap scum (which is grey-white and feels waxy).
Common Causes
- High humidity (above 60% relative humidity)
- Poor ventilation in bathrooms and kitchens
- Condensation on cold surfaces
- Water leaks behind tiles or in walls
- Inadequate extraction fans or blocked vents
- Silicone joints that have lost their mould resistance
Prevention
- Ensure adequate ventilation - run extractor fans during and 15 minutes after showering
- Open windows daily to exchange air
- Wipe down wet surfaces after bathing
- Use mould-resistant silicone for joints
- Maintain room temperature to reduce condensation
Treatment by Surface Type
Natural Stone
Risk level: Medium
Lithofin KF Mildew-Away: spray onto affected areas. Leave 15-30 minutes. Scrub grout lines with old toothbrush. Rinse thoroughly. For natural stone: test first in inconspicuous area. Improve ventilation to prevent recurrence.
- Some mould removers contain bleach which can discolour stone
- Test on natural stone before widespread application
- Do not use chlorine-based products on coloured marble
Ceramics
Risk level: Low
Lithofin KF Mildew-Away: spray onto affected grout and silicone joints. Leave 15-30 minutes. Scrub with brush. Rinse. For deeply mouldy silicone: remove and replace with mould-resistant silicone.
- Ceramic tiles themselves resist mould - it grows in grout and silicone
- Replace silicone joints if mould is deeply embedded
Artificial Stone
Risk level: Low
Lithofin KF Mildew-Away for mould on concrete or terrazzo surfaces. Apply, leave 15 minutes, scrub, rinse. Seal surface afterwards to reduce moisture penetration.
- Concrete can harbour mould in porous areas
- Quartz composite is generally resistant
Cotto Terracotta
Risk level: Medium
Lithofin KF Mildew-Away: spray, leave 15-30 minutes, scrub, rinse. Address moisture source. Seal with Lithofin TC Impregnator after treatment and drying.
- Mould on cotto indicates serious moisture problems
- Porous cotto absorbs moisture that feeds mould growth
When to Call a Professional
If mould is widespread (covering more than 1m²), behind tiles, or in walls, this indicates a building defect that needs professional assessment. A damp surveyor should identify and fix the moisture source. For health-sensitive situations (immunocompromised residents), have mould professionally removed.
Find the right product
Use our Lithofinder to get a personalised product recommendation for your specific surface and problem.