After the severe weather in January, I have noticed patches of mould forming on the ceiling of my rented apartment. It is a new-build unit, and I take very good care of it: I keep it well ventilated, avoid excess moisture, and follow all the precautions I read in a previous Property Clinic article about mould. For that reason, I am concerned that the issue may be linked to the building itself rather than anything within my control.
I do not want to be held responsible for the mould, and I want to ensure the matter is handled correctly. What is the best way to proceed in terms of reporting it, having it assessed, ensuring any necessary repairs or remediation are carried out, and who is responsible for this?
Noticing patches of mould in a new-build rented apartment can be worrying and frustrating, particularly when you take care to maintain good ventilation, avoid excess moisture, and follow the usual precautions to prevent mould growth. For tenants who are conscientious about their living environment, seeing mould appear despite their best efforts can understandably raise concerns that the issue is linked to the building itself rather than anything under their control.
In modern new-build apartments, persistent mould is generally uncommon. Older developments, particularly those constructed in the early to mid-2000s, were more prone to mould due to design or construction deficiencies, such as inadequate insulation, thermal bridging, or poorly designed ventilation systems. Over time, such defects could allow condensation and dampness to develop, which in turn encourage mould growth.
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Today, however, apartments are constructed to significantly higher standards. Modern Building Energy Rating (Ber) requirements ensure that units are thermally efficient, well insulated, and designed to minimise heat loss and moisture accumulation.
Alongside Ber standards, building regulations have also evolved to mandate effective ventilation and heating. These improvements make it far less likely that mould will occur in newly constructed apartments under normal occupation.
Where mould does appear in a new-build apartment, it is often linked to defects in the building fabric or water ingress rather than tenant behaviour. This can include minor cold bridging, insufficient insulation in certain areas, leaks around roofs or windows, or interstitial condensation within walls or ceilings. Depending on where your apartment is located in the building, it could also be linked to leaks from overhead baths/showers or plumbing installations.
As a tenant who maintains good ventilation, uses extractor fans when cooking or showering, avoids drying clothes indoors excessively, and generally maintains the apartment responsibly, you are unlikely to be causing or contributing to the problem.
The correct approach is to report the issue promptly to your landlord or managing agent, ideally in writing, including photographs and dates to document when the mould was first observed. The landlord or managing agent should then arrange for a chartered building surveyor to inspect the property.
This will identify the likely cause of the mould, whether due to water ingress, condensation, or defects in the construction. It will also provide a report detailing recommended remedial works or next steps to resolve the issue.
In summary, persistent mould in a new-build apartment is usually related to the building itself rather than tenant activity. With modern building regulation standards and Ber requirements, such issues are relatively rare, and responsibility for remediation rests with the landlord or developer.
Prompt reporting and consultation with a chartered building surveyor will ensure that the cause is accurately identified and that appropriate, effective remedial works are carried out, protecting both the apartment and your responsibilities as a tenant.
Aidan McDonald is a chartered building surveyor and a member of the Society of Chartered Surveyors Ireland
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