Insulating a Solid Brick Wall from Inside: Heat and Moisture Transfer Analysis of Different Options

Abstract

In the present paper, the thermohygrometric performances of a clay brick wall, with reference to the typical northern Italy’s historical building envelopes, improved with an insulating layer on the inner side, are analyzed. Five alternative insulation materials have been compared: calcium silicate hydrates, fiberwood, expanded polystyrene, stone wool, and aerogel. The dynamic calculation tool WUFI (Wärme Und Feuchte Instationär) was adopted for simulating the realistic transient hygrothermal behavior of the multilayer building components exposed to natural local weather. Based on the climatic data of Turin and Tarvisio, chosen as representatives of the northern Italy urban centers and mountain localities, respectively, rain and solar radiation effects, water content distribution through the multilayered wall, mold formation in critical areas of the wall, and heat and vapor flows through the wall surfaces have been evaluated. Finally, the vapor barriers installation affecting the amount of condensate have been considered and compared with the prediction of the simplified steady-state Glaser method commonly adopted in the professional practice of building design. The results of the study indicate that a deep knowledge of the thermohygrometric performance of the wall assembly, together with a reliable/realistic condensation risk analysis, are key factors for a proper internal wall insulation, with particular reference to the actual need of the vapor barrier.