Helsinki Vocational College is one of the largest vocational schools in Finland. Helpa, built in 1978, is one of the five campuses of the College. This protected building was designed by the same architects as the Temppeliaukio Church: Timo and Tuomo Suomalainen. 

”Helpa was reaching the end of its service life, and the new study programmes also needed new kinds of facilities,” says Project Manager Jari Rosanti from the Construction Contracting Services of the City of Helsinki, responsible for the construction of infrastructure and public spaces in Helsinki. The most significant changes included the addition of 13 new, modular teaching kitchens and bakeries designed together with the teachers to meet the needs of modern working life. 

The school remained in operation thanks to successful phasing

One of the most central challenges was the phasing of the project. The 46-million-euro project was implemented in three years, with each phase lasting approximately a year and covering approximately 7,000 square metres. The College stayed in operation throughout the modernisation project. 

“The phasing of the work was a big challenge, and there were a lot of surprises in the demolition phase, in particular,” Rosanti says. ”However, Sweco quickly gave us feasible additional plans.” According to Rosanti, smooth co-operation between users, designers, contractors and the client organisation is an absolute requirement for a successful and phased implementation of a project as extensive as this one. 

”The project stayed on schedule and within the budget, even if it was hard sometimes,” says Tommi Mutanen, Sweco’s Project Manager for the structural design and the person in charge of the worksite. ”The first phase was the most extensive and difficult one, and we were only a little behind after that. But we managed to pick up the pace in the other phases.” 

The old building set the pace for the modernisation. For example, the HVAC routings were embedded in the existing structures, while weather protection required special attention. “We couldn’t let the structures get wet at any point,” Mutanen states. 

The project team also performed air leakage tests and prepared the necessary moisture control documents in connection with the waterproofing renovations. The structures were dismantled down to the load-bearing frame, and the College got a new facade and roof. “In addition to this, half of the 700 windows were renovated and half were replaced. All thermal insulations were also renovated to meet today’s standards,” Mutanen says. 

Building services equipment on the roof and in the basement

There was no room for modern technology in the building due to the low ceilings and long distances between pillars. The solution was building new HVAC machine rooms on the roof. During the design process, the size of the machine rooms increased: As a result, there are more than 1,000 square metres of HVAC equipment on the roof. 

“The load-bearing structures also needed to be strengthened since, on a flat roof, the edges of the machine rooms may have piles of snow on them,” Mutanen says. The roof’s prestressed double-T slabs made of reinforced concrete were strengthened with adhesive steel plates. “Adhesive reinforcing of double-T slabs means reinforcing a structure in class 1, which is considered an exceptionally demanding design project.” 

The electrotechnology control centre was placed in the basement, which was an efficient way of using the indoor spaces. “We designed a technical channel under the base floor, which is partly ventilated and partly on the ground,” Mutanen says. “The solution is cost-efficient since we in any case needed to remove the floors to be able to install sewer lines, drains, radon piping and thermal insulation.” 

Better indoor conditions with less energy consumption

Since the College was in operation throughout the project, the teaching facilities and temporary facilities had to be carefully protected. “In addition to weatherproofing, the construction site was isolated so that the impurities wouldn’t enter the teaching rooms,” Mutanen says. The planning also aimed to reduce the disturbances caused by the worksite. “There’s always noise, but we managed to reduce the levels with airproof noise walls.” 

The renovation project improved the indoor conditions and the functionality of the facilities significantly. “The users are happy with the modern facilities, and we have received particularly positive feedback for the teaching kitchens with the new appliances,” Rosanti says. “The indoor air conditions of the College are now at a new and better level. It is also consuming substantially less energy.”