Assessment of the Impact of the Location of the Insulation Layer on the Humidity Regime and Heat Transfer Resistance of the External Building Envelope

The influence of the location of the insulation layer of external enclosures on the humidity regime and heat transfer resistance of the external opaque building envelope structures: with a layer of insulation on the outside and inside, as well as without insulation, was assessed by the numerical method, taking into account the thermal physical characteristics of all materials of the external wall of the building. Two types of wall panels were experimentally investigated. It is shown that the insulation of the structure with a layer of PSB-15 polystyrene foam, 100 mm thick, can reduce heat losses through the wall panel by almost half. The influence of heat transfer resistance on the performance of the building's heating system was assessed, taking into account the parameters of the external environment and the parameters of the indoor microclimate in a dynamic mode. Thus, in the case of building envelopes made of multilayer wall panels with insulation, the temperature drop reaches ± 5 °C, which meets the requirements of DBN B.2.6-31:2021, in contrast to building envelopes made of brickwork without insulation. The obtained research results allow us to clearly define the design solution for external enclosures already at the stage of developing project documentation. For each specific design solution, the optimal placement of the insulation was determined based on the condition of no moisture accumulation in the thickness of the studied structure. With a correct assessment of the moisture regime, structures with internal insulation cannot be used. For such a structure, moisture condensation occurs in the thickness of the insulation, which is unacceptable. It has been shown that brickwork without insulation, in order to maintain the estimated period of its optimal operation, requires measures to bring its thermal resistance to heat transfer to the normalized value or to arrange a more intensive air exchange in the building premises. However, the latter may cause additional energy consumption. The feasibility of this or that approach should be considered in more detail in terms of comparing operating costs and energy losses of the building. It is proved that in the design of residential and public buildings, the results of the assessment of the humidity regime of external envelope structures and the energy performance of the building for compliance with the current requirements are a very important criterion when choosing a supplier of building materials from a wide range of products on the market, which can be decisive in making a specific design decision.