Y2024-02 Collapse of thick insulated rendering facade in Kontula, Helsinki on 30 July 2024

The thick insulating render on an end wall of a block of flats in Kontula, Helsinki collapsed suddenly on Tuesday 30 July 2024. No one was injured in the accident, but the housing company incurred significant costs.

The thick insulating render system on the site had been exposed to installation errors during the construction phase, and its installation would have required carefully following instructions. Planning quality assurance and identifying critical work stages affect the success of work. The supervision of the construction had not concerned all critical implementations of the structure. Without active and competent technical supervision, significant deficiencies may be left in the structures.

As there was no clear agreement on the necessary measures and timetables for the thick insulating render construction project, responsibility for management had, to some extent, shifted from the developer to the contractors. In housing companies, laymen are often responsible for significant property assets and their management. In practice, it is difficult for a housing company, without the support of an expert, to check that a company in the construction sector has the competence, appropriate powers and other necessary prerequisites for performing work.

The construction project had not progressed in accordance with the terms of the building permit granted by the building control authority, and the project had failed to keep the authority informed of the work phases. The authority had not intervened in the process. Quality control had mainly been based on the project’s self-monitoring. Supervision by the building control authority may remain ineffective due to insufficient contact with the authority.

The condition assessment of the site had not provided information about the state of the thick insulation render structure. The removal of the old surface layer of the rendering with techniques that cause vibration and the increase in mass caused by the new surface contributed to the later collapse of the structure. Condition assessments do not always reveal hidden weaknesses, as they start with the most obvious shortcomings.

The low number of brackets failed to support the render system load, which finally collapsed unexpectedly. The failure to support the structure of the brackets was continuous by nature, only stopping in the seams that surrounded the area. The life and health risk resulting from the possible collapse of façade structures is not taken into account in the same way as for other suspended-type structures.

1. The Finnish Real Estate Federation advise and instruct housing companies to verify that the developer’s supervisors and other experts used in renovation projects have sufficient technical competence and expertise in the planned renovations.
2. The Finnish Real Estate Management Federation guide and support housing management companies in verifying that the technical property managers and consultants used by housing companies in renovations have sufficient technical expertise on the intended renovations.
3. The Rakennustuoteteollisuus RTT raise awareness among construction sector operators of the criticality of the structural load-baring capability of thick insulating renders.
4. The Ministry of the Environment ensures that the building control authorities intervene in construction projects through supervisory measures if the building permit conditions set for the projects are not met.