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By order of KredEx, a survey “Constructional-physical state of renovated buildings having been in use for at least one year” conducted by Estonian Union of Cooperative Housing Associations and Tallinn Technical University has been completed, the main purpose of which was to determine the constructional-physical state and internal climate of apartment buildings belonging to the sample, as well as the energy consumption situation. The survey is necessary to guarantee the quality of renovation methods not to repeat the mistakes made.
The survey was based on four five-storied apartment buildings having applied widely used renovation methods: brick and large panel building with wool used for additional insulation of outer walls, and a brick and panel building with foam polystyrene used for additional insulation of outer walls.
The survey revealed that often the customer lacks an understanding of all constructional-technical issues that an integrated renovation process of a building should include. Usually, a complex renovation of a building is understood as insulation of the building shells, renovation of the finishing, exchange of the pipelines of leaking technical communications, and modernisation of the electrical system. One of the major problems is that as a rule, renovation of the ventilation system is left out of the scope of renovation work.
According to the survey of internal climate of buildings it may be said that the main problems in apartment buildings arise from insufficient air exchange, which is based on insufficient or not functioning ventilation system. As a consequence of poor air exchange, the relative humidity and carbon dioxide concentration levels in apartments are high. In the event of insufficient ventilation, there is a considerable addition of humidity in the rooms, which by condensation can cause mould on the cooler internal surface of the outer shell, which in turn is a real danger to the health of people. Due to that, it is important to pay attention to ventilation while renovating.
The survey revealed that by additional insulation of buildings, heating expenses have been decreased and the technical state of the envelope structures has been improved, but the envelope structures do not correspond to the minimum requirements to energy efficiency. To ensure heat conductivity of outer walls of all examined sites according to requirements, according to specialists, instead of a 100-mm additional insulation, 150-200-mm external insulation should be used. According to the survey, envelope structures are recommended to be insulated only from outside, as internal insulation does not eliminate cold bridges in the structure or decrease heat loss. The whole facade of a building should be covered with additional insulation, and special attention should be paid to walls bordering with balconies and loggias, as leaving those uninsulated means continued large heat loss through uninsulated envelope structures.
On the other hand, moisture-technical state of additionally insulated outer walls of buildings was good. Presumable moisture-technical difference between outer walls insulated with foam polystyrene and mineral wool was not confirmed in the present survey, i.e. the moisture content of outer walls insulated with foam polystyrene and mineral wool were basically equal.
According to specialists, it is important to renovate/balance the heating system after the insulation of a building. Renovated heating system makes it possible to use heating energy more effectively, and adjust it to the needs of people. According to the summary of the survey, complete renovation work is technically and economically more expedient than work performed by single processes.
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