Repairs after an indoor air survey

Repairs or other measures can be implemented quickly if considered necessary based on the results of an indoor air survey to allow continued use of the facilities. Sometimes repairs mean the complete renovation or refurbishment of the building.

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Fast measures to improve indoor air quality

  • Adjusting supply air temperature and changing ventilation system operating hours
  • Adjusting and bleeding the radiator system if necessary
  • Opening any blocked sewers

  • Cleaning the ventilation system
  • Adjusting air volumes
  • Removing any fibre sources from the ventilation system
  • Water damage repairs and other minor repairs
  • Acquiring air filters in accordance with the city guideline

  • More efficient cleaning/removal of accumulated dust from high surfaces
  • Relocation of furniture/decluttering
  • Reducing the number of users in the facilities
  • Ventilation through windows to improve air flow

Repairs and other measures after surveys

When the indoor air survey has been completed, a decision on the necessary repair measures will be made. The necessary repairs may involve the entire building, part of it or a specific technical system such as the ventilation system. The planning of extensive repairs takes time. Some repairs may also require a building permit.

The primary method of repair is to eliminate the cause of the damage and repairing the damage, as well as repairing or replacing any faulty equipment. The possibility to keep using the facilities during the repair work will always be reviewed on a case-by-case basis. Operations sometimes need to be moved to temporary facilities either completely or in part. Read more about temporary facilities.

If the surveys have revealed microbial damage in the building or fibre sources or other impurities that attach to furniture, and the operations are moved elsewhere, the furniture and other movables will be thoroughly cleaned. The City of Helsinki has its own set of guidelines for cleaning movable objects, which are based on instructions by the Finnish Institute of Occupational Health.

If the furniture and movables are free of visible mould or obvious odours, careful cleaning usually suffices. Hard surfaces can be vacuumed and cleaned, and textiles should be washed at 60°C or more or taken for chemical cleaning. Textiles, padded furniture and any similar movables with clear spots or a noticeably mouldy odour must be disposed of.

Limited repair projects

Limited repair projects include the repair of local moisture damage and the improvement of a building’s ventilation system and building automation system. For example, if the indoor air issue is caused by fibres originating in the ventilation system duct silencers, the silencer materials will be replaced or coated.

Postponing repair projects before a renovation

In a postponing repair project, the aim of the repairs is usually to ensure that the facilities can be used until a refurbishment or another major renovation, at which point the damaged structures will usually be replaced.

Sealing repairs are an example of a postponing repair project. The sealing of structures prevents any release of impurities into indoor air. Sealing repairs are carefully planned and carried out, and their success is verified by tracer tests as a rule.

In addition to sealing the structures, negative pressure can be generated in the damaged structure or space, meaning adjusting the pressure so that air does not flow from the damaged area towards the surrounding areas. Negative pressure is used in crawlspaces under buildings or in underfloor duct channels, for example. 

Over-pressurisation of the building or some rooms and the installation of room-specific ventilation units are also considered postponing repair projects.

Renovation or refurbishment

In some cases, problems are so extensive that a complete renovation or refurbishment of the building is necessary. A renovation means that the building or an individual space or structure within the building is repaired to be as good as new. On the other hand, refurbishment improves the quality level of the building to significantly above that of the original building.

The users of the facilities must usually be moved to temporary facilities for the duration of a renovation, refurbishment or other extensive repairs. The planning and implementation of a refurbishment take several years.

Monitoring of repairs

After the repairs, their success can be monitored by taking dust samples from surfaces or by measuring the differential pressure in the building or chemical impurities in indoor air. If the indoor air quality is still considered inadequate after the repairs, we will check whether all the necessary measures have been carried out. 

In principle, facilities are considered healthy and safe when the sources of the indoor air impurities, the causes of the damage and the damaged structural elements have been removed or repaired so that they are no longer in contact with the indoor air. This requires that the problem areas have been thoroughly inspected, and all detected faults and defects have been properly repaired.

Sometimes the symptoms of some persons may persist even after careful repairs. In the event of a difficult problem, some people may be unable to return permanently to the building, even after it has been repaired. If symptoms persist despite repairs, the symptomatic persons can be helped by offering them the opportunity to move to another unit or location, for example. The causes of the symptoms and means to recover from them are explored with the health care services. The site supervisor should also be informed of the symptoms so that they can forward the information to the person responsible for the maintenance of the facilities. In cooperation with other parties, an indoor air specialist assesses the success of the repairs, and decisions on how any deficiencies will be repaired are made after that.