Household activities, such as cooking, washing and “people’s breathing”, are the primary source of condensation which causes damp and mould in Dublin City Council’s flat complexes, according to a new report from the local authority.

“A person exhales approximately 200ml of water vapour per hour while awake and approximately 20ml of water vapour per hour during sleep,” the report pointed out.

The council was in 2017 the subject of a ruling from the European Committee of Social Rights because of the condition of some of its older blocks of flats. The committee found the human rights of tenants had been breached because of living conditions which included persistent damp and mould.

The council plans to redevelop more than 6,000 of its oldest and most dilapidated flats, but said the project will take up to 15 years to complete. In the interim it has undertaken to examine the causes of condensation and mould.

The report, from the council’s housing maintenance division, to be presented to councillors on Thursday, conceded that the age and structure of flats and interventions such as the installation of heating and double glazing had contributed to increasing humidity. However, tenant activities such as “cooking, washing and using unflued gas heaters, as well as people’s breathing, provide the primary sources of moisture that cause humidity indoors”, it said.

When breathing was combined with washing, boiling kettles and cooking, “in a property of four people, each will contribute approximately four pints of moisture per day . . . this will add up to over 110 pints of water vapour per week, a huge volume which must go somewhere.”

Ventilation systems The council is trialling four products to combat condensation and mould: two involve the installation of ventilation systems, one is a paint that fights mould, and the fourth is an insulation product that heats walls to stop condensation forming.

However, guidelines needed to be issued on “unreasonable tenant activities”, it said. “A common occurrence is to find vents stuffed with newspapers or old clothes to stop the drafts.”

It recommends tenants not dry clothes on racks indoors, keep heating at “at least 20 degrees” and open windows.