A housing company repaired old war years’ damage during pipe renovation

The renovation of limited liability housing company Kolmas linja 5 in Kallio, Helsinki, began with water damage repair. As the project went on, it was expanded to include a thorough renovation of the pipes and ventilation. Throughout the project, the housing company remained focused on the most important aspect: comfort of living.  

This stone house, built in 1940, differs from the other blocks of flats on the same street thanks to features like its round courtyard. Another special feature can be found in the building’s history. Air raids that took place during the war left their mark on the building’s ventilation ducts and indoor conditions. The housing company also made an unconventional decision of having the pipes and ventilation system renovated simultaneously.  

‘In 2016, five separate wet areas in the building suffered water damage, and during the repairs we surveyed the pipes thoroughly,’ says Dennis Murto from Sweco, who was in charge of the pipe renovation plans. The housing company had not been planning to renovate the building’s pipes for another 10 years, but the pipes were discovered to be severely corroded. ‘They could have caused another leak at any moment.’ 

Understandably, this was unpleasant news to the housing company, but the facts were undeniable. However, there was more. ‘Because of the air raids during the war, the ventilation ducts were in an exceptionally poor condition and the ventilation system had not been working properly for decades,’ says Murto. 

Possible repairs to the ventilation system had already been discussed 15 years previously, due to the problems with the indoor air quality. Back then, it had been deemed too costly. Now, however, they decided to fix it while other repairs were taking place. ‘The standards of living and occupants’ level of requirements have risen, so it was time to improve the conditions indoors,’ says Project Manager Eino Rantala from Ekosto. 

Better indoor air, comfort of living and energy efficiency

Thorough ventilation repairs are seldom performed at the same time that a building is undergoing pipe renovation. In fact, the housing company on Kolmas linja initially planned to simply mechanise the exhaust air system. 

‘Ultimately, the housing company decided to go with a more modern solution where the air intake is also mechanical. This system also includes heat recovery,’ says Murto. All the old ventilation ducts will be dismantled, and the channels constructed with building materials will be replaced with modern pipes made from sheet metal. Simultaneously, the building’s electrical systems and the wet areas in all 69 flats will be renewed. 

The occupants will get to enjoy the finished results in autumn 2020. ‘The indoor air quality, living conditions and electricity consumption options will improve notably for the residents,’ says Rantala. ‘Furthermore, the heat recovery will reduce heating costs and there will be no more risk of water damage.’ 

Mutual trust helped to overcome the challenges

A large number of architects, structural designers and HVAC and electrical engineers from Sweco took part in planning the renovation. In addition to this, technical monitoring was part of the package. The contract was worth 4 million euros, making it extremely important for the designers to support the needs of the contractor and the housing company. 

‘As the site required a variety of measures, it was impossible to perform a complete assessment before beginning the work and a relatively large number of modifications along the way were needed,’ says Rantala. This made it necessary for the planning and monitoring to be flexible, to allow the contractor to stay within the agreed schedule and budget. ‘We have been seeking solutions to every problem together, and the designers have come up with some truly innovative ideas!’ 

The board of the housing company has also put a lot of time and effort into the project. Making new decisions at various stages of the project has meant additional meetings and has required smooth collaboration. 

‘At the very beginning, we discussed the way in which the project would be run, and all the big decisions had already been made by the time we got down to the finer details,’ Rantala says. ‘In addition, it was very helpful that both the housing company board and building management have people with extensive knowledge about these matters. When you can trust one another, you can also work well together.’ 

Rantala also believes that Sweco’s employees’ ability to motivate others has had a significant impact. ‘It is very important to explain things in a way that engages all the participants. People and their concerns need to be heard. You should never lose your temper or hope!’