Mould Removal & Remediation Services Ireland

Why Mould Is So Common in Ireland

Ireland has one of the highest rates of indoor mould in Europe, and the reasons are largely climatic and structural. Average relative humidity in Ireland sits between 75% and 90% for most of the year. When that humid air meets cold surfaces — single-glazed windows, uninsulated external walls, thermal bridges around window reveals, and poorly ventilated bathrooms — condensation forms. And where condensation persists, mould follows.

The problem is compounded by Ireland’s older housing stock. Approximately 40% of Irish homes were built before 1970, many with solid walls, no cavity insulation, and minimal ventilation by modern standards. Even newer properties can suffer from mould when extract fans fail, trickle vents are closed, or buildings are sealed too tightly without adequate mechanical ventilation.

Commercial properties are not immune. Office buildings with sealed windows and poorly maintained HVAC systems develop mould in ceiling voids and behind wall linings. Hotels suffer from bathroom mould when extract fans cannot keep pace with guest usage. Healthcare facilities face mould risks in plant rooms, storage areas, and any space with variable heating patterns.

The bottom line: mould in Ireland is not a sign of a dirty property. It is a building physics problem that requires a building physics solution. That is exactly what Optus Glean delivers.

Health Risks of Indoor Mould

Mould is not just unsightly. It is a genuine health hazard recognised by the World Health Organisation, the Health Service Executive, and the European Environment Agency. The health risks include:

• Respiratory conditions — Mould spores trigger asthma attacks, allergic rhinitis, sinusitis, and bronchitis. The HSE links indoor mould exposure to a 30–50% increase in respiratory symptoms.
• Allergic reactions — Coughing, sneezing, watery eyes, skin rashes, and throat irritation are common responses to mould exposure, particularly in sensitive individuals.
• Mycotoxin exposure — Certain moulds, including Stachybotrys chartarum (black mould) and Aspergillus species, produce mycotoxins that can cause serious illness with prolonged exposure, including hypersensitivity pneumonitis and immune suppression.
• Vulnerable groups — Children under 5, elderly people over 65, pregnant women, and those with existing respiratory conditions or compromised immune systems are at significantly higher risk.
• Mental health impact — Living or working in a mouldy environment is associated with increased anxiety, depression, and reduced quality of life. The stress of visible mould and the feeling of an unhealthy environment take a measurable psychological toll.

If you can see mould or smell a persistent musty odour in your property, do not ignore it. The longer mould grows, the deeper it penetrates building materials and the more spores are released into the air you breathe.

Our Mould Removal Process

Optus Glean follows an IICRC-aligned mould remediation process. We do not just wipe mould off surfaces — we eliminate it at the source and prevent it from returning.

1. Assessment and Moisture Survey — We inspect the affected areas, identify the type and extent of mould growth, and use moisture meters and thermal imaging to locate the source of moisture. Every remediation begins with understanding why the mould is growing, not just where.
2. Containment — For moderate to severe mould, we seal the affected area with plastic sheeting and use negative air pressure to prevent spores from spreading to clean areas during removal. Our teams wear full PPE including P3 respirators.
3. Removal — Surface mould on non-porous materials is removed with specialist biocides. Mould in porous materials (plaster, plasterboard, wood, grout) is treated with penetrating fungicides that kill mould roots deep within the material. Severely affected materials that cannot be salvaged (saturated plasterboard, rotten timber) are removed and disposed of as contaminated waste.
4. HEPA Vacuuming and Air Scrubbing — All surfaces in the treatment area are HEPA vacuumed to remove loose spores. Air scrubbers with HEPA filtration run throughout the remediation to capture airborne spores and reduce the spore count to safe levels.
5. Anti-Microbial Treatment — After removal, we apply a long-lasting anti-microbial coating to treated surfaces. This coating inhibits mould regrowth for 6 to 12 months and creates a hostile environment for spore germination.
6. Prevention Plan — Every client receives a written prevention plan identifying the root cause and recommending specific actions: improved ventilation, dehumidification, insulation upgrades, or heating pattern changes. We address the cause, not just the symptom.

Residential Mould Removal

Mould in the home is distressing, particularly when it affects bedrooms and living spaces where families spend the most time. The most common locations for residential mould in Ireland are:

• Bathroom ceilings and walls (inadequate extract ventilation)
• Bedroom window reveals and external wall corners (thermal bridging and condensation)
• Behind wardrobes and furniture against external walls (restricted airflow)
• Kitchen ceilings (steam from cooking without adequate extraction)
• Attic spaces and roof voids (roof leaks or insufficient loft ventilation)
• Utility rooms and hot press areas (drying clothes indoors without ventilation)

Optus Glean provides residential mould removal across all 26 counties. We work around your schedule, minimise disruption, and leave your home safe and clean. For tenants, we provide documentation that landlords can use for insurance claims or grant applications.

Commercial Mould Removal

Mould in commercial properties creates health and safety risks, reputational damage, and potential regulatory issues. We provide mould remediation for:

• Offices and corporate buildings (HVAC-related mould in ceiling voids and behind partitions)
• Hotels and hospitality (bathroom mould, laundry areas, basement storage)
• Healthcare facilities (plant rooms, storage, patient areas — HIQA implications)
• Retail units (stockrooms, basements, units with poor ventilation)
• Schools and creches (particular urgency due to vulnerable occupants)
• Apartment common areas (stairwells, bin stores, plant rooms)

Commercial remediation is carried out with minimal disruption to your operations. We work outside business hours where possible and provide full documentation for compliance, insurance, and audit purposes.

Landlord Obligations: Mould in Rental Properties

If you are a landlord in Ireland, you have a legal obligation to address mould caused by structural defects, poor ventilation, or inadequate insulation. The Housing (Standards for Rented Houses) Regulations 2019 require that rented properties be maintained in a proper state of structural repair and free from damp and mould arising from structural causes.

The Residential Tenancies Board (RTB) can adjudicate disputes where tenants report mould and landlords fail to act. Local authorities can inspect and issue improvement notices. In extreme cases, prohibition notices can render a property unlettable until remediation is complete.

Optus Glean works with landlords and property managers to resolve mould issues efficiently. We provide a detailed report identifying the cause, carry out the remediation, and deliver documentation suitable for RTB records, local authority inspections, and insurance claims. For landlords managing multiple properties, we offer a priority response service and volume pricing.

If your rental property has a mould problem, the cost of professional remediation (€300–€2,500) is a fraction of the cost of an RTB complaint, a local authority enforcement action, or a personal injury claim from an affected tenant.

Mould Prevention: Stopping It Before It Starts

Remediation without prevention is a temporary fix. Optus Glean addresses the root cause of every mould problem we treat. Common prevention measures we recommend and, where appropriate, implement include:

• Ventilation improvements — Installing or upgrading extract fans in bathrooms and kitchens, ensuring trickle vents are open and functional, and recommending mechanical ventilation with heat recovery (MVHR) for sealed buildings.
• Dehumidification — For properties with persistent high humidity, we recommend appropriate dehumidifiers and advise on optimal placement and settings.
• Insulation and thermal bridging — We identify cold spots and thermal bridges that cause condensation. While we do not carry out insulation work ourselves, we provide detailed recommendations for insulation contractors and can coordinate with them.
• Heating patterns — Consistent low-level heating is more effective at preventing condensation than intermittent high-temperature heating. We advise on heating strategies that balance mould prevention with energy costs.
• Behavioural guidance — For residential clients, we provide practical guidance on drying clothes, cooking, showering, and furniture placement to minimise condensation risk.

Combined with our vacant property cleaning and end-of-tenancy cleaning services, Optus Glean can prepare mould-affected properties for new occupancy, ensuring they are clean, treated, and set up to prevent recurrence.