Housing and health

Proper ventilation is a prerequisite for good indoor air quality. Poor or inadequate ventilation can affect the residents’ health negatively. Room temperature and humidity have a direct effect on living comfort.

Day-to-day activities and the building’s structures constantly release impurities and moisture into the air. To reduce indoor air pollution, all residential buildings must be adequately ventilated. Buildings can either have a natural ventilation system or mechanical ventilation. Ventilation must not be prevented, for example, by closing valves or make-up air openings.

• The effectiveness of natural ventilation depends on the temperature difference between the outdoor air and the indoor air, wind direction and wind speed. In the summer, natural ventilation usually works poorly, and additional ventilation through windows is required.
• Mechanical exhaust ventilation is the most common type of ventilation in homes. A separate exhaust fan is used to remove air from the building. The fresh make-up air comes through windows or separate make-up air vents. Mechanical exhaust ventilation ensures that the building is ventilated properly during all times of the year.
• A mechanical supply and exhaust air system includes at least two separate fans as well as supply and exhaust air channels with valves. The supply air is usually led to the areas where most time is spent. The ventilation system may also include filters, silencers and a heat recovery system that require regular maintenance and cleaning. Heat recovery saves energy.
• Mechanical ventilation must be kept on at all times.

Indoor air quality can be affected by pollutants from building materials. Unusual odours and symptoms of residents can indicate a potential indoor air quality problem. In some cases, volatile organic compound (VOC) measurements can be used to determine the origin of odours.

Excessive noise affects living comfort, and noise pollution can harm the health of residents. Noise disturbances can prevent you from falling asleep, reduce the depth of sleep or wake you up at night. Thus, noises reduce the restorative effect of sleep and rest.

Pollution may enter the apartment from other parts of the building through structural leaks or incorrect ventilation. For example, the smell of cigarette smoke coming from one apartment to another is a health hazard according to the Finnish Health Protection Act. Other odours, such as sewer gases or cooking smells, coming into the apartment aren't acceptable either.

Radon is a problem associated with apartments and other living areas that are in contact with the ground. Radon is an odourless, tasteless and colourless radioactive noble gas that comes from soil and rocks. You can’t see or smell radon in any way. Radon enters the home through cracks and porous materials in the foundation. The amount of radon in the room air can be measured with radon measuring instruments. Radon detector measurements are provided by commercial operators as well as the Finnish Radiation and Nuclear Safety Authority. Further information on service providers and radon measurement methods that are approved by the Finnish Radiation and Nuclear Safety Authority is available at stuk.fi.

Research evidence shows that moisture damage in buildings is linked to the following illnesses and symptoms:

• Respiratory symptoms in people with asthma, upper respiratory symptoms, cough, wheezing, dyspnoea, development of asthma.
• Respiratory infections, allergic rhinitis, general symptoms (fatigue, headaches, nausea), atopic dermatitis.

Source: The Finnish Medical Society Duodecim, 2016

However, the symptoms aren’t always caused by microbial growth in the building. If you suspect that your symptoms are caused by microbial growth, you should mention your suspicions when you visit the health centre. However, with the currently available methods, it is difficult to establish a causal relationship between symptoms and microbial growth in the building.

Causes of moisture damage

Any building material will be damaged if there is enough moisture in the building. The causes of moisture damage include:

• pipe leaks, improper installations
• insufficient thermal insulation (humidity in the room condenses on cold surfaces)
• insufficient ventilation
• poor subsurface drainage and surface drainage
• a foundation that is too low or inadequate subfloor ventilation
• inadequate waterproofing or use of incorrect materials in wet rooms
• improper roof structures, no eaves gutters (rainwater penetrates wall structures)
• insufficient roof ventilation

Detecting moisture damages

Sometimes microbial growth can be visible on the interior surfaces of a building, but often it is hidden under the surface. In this case, the following things may be signs of moisture damage or microbial growth:

• stale indoor air, musty smell or smell of mould (damage is possible even if there’s no smell)
• flaking paint or discolouration on indoor surfaces, peeling wallpaper or plastic carpet, open seams
• discolouration of parquet flooring in certain areas
• falling tiles or clinkers, discolouration of seams
• paint on the foundation wall is flaking
• white salt on brick/concrete structures
• constantly foggy windows
• people who spend time in the building experience symptoms or illnesses that are alleviated or disappear when they are elsewhere
• a large number of insects (silverfish, ants, booklice)

If you suspect moisture damage in the building, you should examine all moisture-prone structures in the building and continue investigating even after you find the first signs of damage. Once the moisture damage or microbial growth has been found in the building, you should find out the cause and extent of the structural damage quickly and make a plan for corrective actions.

You should also check the surroundings of the damage even if the structures seem healthy. Moisture or dormant microbial growth in the repaired structure can quickly cause the same damage to reoccur. The former structure and materials used must be carefully examined before a repair plan is drawn up. To find out the extent of the damage and what materials have been used, the structures should be dismantled.

Primary measures if moisture damage is suspected

Moisture damage should be investigated and repaired without delay. If the moisture damage is not repaired, it usually leads to microbial growth. By repairing the damage, health hazards can be prevented. Repair costs will also be lower if the damage isn’t widespread.

If you live in a building with multiple housing units, please contact the representative of the building (the building manager, the Chair of the Board, the landlord) in issues related to moisture damage. As a rule, the owner of the building (sometimes also the developer) is obliged to investigate the causes and extent of the damage in the building’s structures and to correct the deficiencies. Qualified professionals should be used to identify the moisture damage as well as to plan and carry out the repairs.

The greater the damage, the more detailed investigations are needed to find out the condition and technical functionality of the structures. Before attempting to repair the structures on your own, discuss your plans with a representative of the property owner. In terms of possible permits you may need, please contact the Building Control unit of the City of Vantaa.

Any requests should be submitted to the Environment Centre in writing. You can use a form provided by the Housing and Health Department or write the request yourself. Before submitting the request, please consider what should be the focus of the investigations and repairs in the apartment.

It will help the investigation if you obtain information regarding any previous moisture damage in the apartment or related repairs. The inspector will assess what measurements and inspections are necessary to investigate the moisture damage and possible health hazards.

Find out how maintenance and repairs are organised in your building. The basic requirements for healthy housing conditions include proper ventilation, intact thermal insulation and waterproofing as well as ensuring dry structures. If shortcomings are identified in these areas, the problems should be addressed swiftly. Postponing the repairs can lead to a health risk and much greater damage and more expensive repairs.

The inspector will decide independently which investigations, samples or measurements are required to assess the existence of the health hazard.

In the most clear cases, for instance, in the detection of moisture damage and microbial growth, organoleptic observations are sufficient. The damaged material can be examined in a laboratory, and moisture in structures and surfaces can be measured using a surface moisture indicator. The level of microorganisms in the indoor air of an apartment with microbial growth rarely differs from the levels found in apartments where no microbial growth has been detected. Therefore, the concentration of microorganisms in the indoor air is measured only rarely and only in cases that are difficult to investigate. In addition, air samples don’t usually indicate where the microbes come from.

If the moisture problem and microbial growth can be otherwise detected, it isn’t necessary to measure the concentration of microorganisms in the dwelling.

The first inspection is free of charge. If necessary, further investigations may be carried out at the expense of the property owner.

After the inspections and investigations have been carried out, the health engineer will prepare an inspection report, which may require the property owner to take action. If the property owner fails to carry out the required further investigations and repairs, the health protection authority may order the repairs to be carried out by a given deadline. If necessary, a conditional fine may be imposed for failure to carry out the repairs. The party commissioning the repairs, usually the property owner, is responsible for the adequacy of the repair work and for monitoring the work.

If necessary, inspections will be carried out after the repairs have been completed.