The City of Helsinki's Pihkapuisto primary school and Kaunokki daycare centre in Malminkartano stayed in use until spring 2025, even though the older part of the building had reached the end of its service life. Their use was secured by overpressurising the building and by Loopshore's continuous pressure difference and indoor condition monitoring, which the city ordered in stages from 2021 onwards.
According to the city's assessment, the older part of the building was in poor condition and had reached the end of its service life. A renovation and an extension were planned, but construction would only start years later. The question was whether the existing premises could be used safely until then, or whether the school and the daycare centre would have to move to temporary premises earlier.
Overpressure and continuous monitoring
The building was overpressurised. When the pressure indoors is slightly higher than outdoors, air flows outwards through the structures and not from the structures into the indoor air. Whether the pressurisation worked had to be verified all the time, however, because the pressure difference varies with the wind, the outdoor temperature and the use of the ventilation.
Loopshore measured the pressure difference across the building envelope with six pressure difference sensors and the indoor conditions with six Loop One devices. The measurement data was transferred continuously to the air quality service, and a notification was sent whenever an alert limit was exceeded. An expert compiled a report on the results three times a year. The report assessed the indoor air quality and how well the pressurisation worked.
In its procurement decision, the city described the monitoring as a test of a new kind of measurement method and gave this reason for the follow-on orders (our translation):
"As the first year's measurement proved to work, the following years' monitoring measurements were also ordered from the same supplier in stages, in order to ensure that the premises remained usable until the start of the planned renovation and extension works."
Temporary premises only when the works began
The monitoring continued until the end of May 2025. The school and the daycare centre moved to temporary premises in summer 2025, and the demolition of the old part of the building began right after that. The premises thus stayed in use for about four years from the start of the monitoring, and the users did not have to be moved to temporary premises before the works were about to begin.
The city's own estimate gives an idea of what temporary premises cost: in the project plan, the premises cost of temporary premises for the Pihkapuisto school and daycare centre was estimated at up to about 1.4 million euros a year.
"The pressure difference monitoring carried out with Loopshore was accurate and worked well. Continuous measurement with expert reports verified the effects of our measures, and there was no need to move to temporary premises. This brought significant cost savings."
City of Helsinki, Urban Environment Division, Premises Services
www.hel.fi/kaupunkiymparisto
When a building has to last a few more years
Continuous pressure difference and indoor condition monitoring suits a building whose renovation or replacement is still being planned but which has to be used safely until then. The measurement shows whether the measures that keep it usable work every day, not just on the day of an inspection, and the reports give decisions a basis.
We are happy to tell you how monitoring would suit your building.
Don't guess, measure.