Influence of Spacer Frames for Wooden Roof Windows on the Formation of Surface Condensation

Abstract

This study reports the thermal characteristics of windows installed in the roof cladding of a block of flats in the second temperature zone of the Czech Republic, with boundary conditions for the design value θse = -15 °C, according to the national standard ČSN 73 0540-3 (2005). The thermal behaviour of these elements was evaluated with regard to the condensation on roof windows, with four different types of spacer frames and the given boundary conditions, for maintenance of the thermal and technical humidity comfort of the interior. The tests of the surface temperatures of the diagnosed glazed roof units at the glazing of the wooden windows demonstrated that the SGG composite spacer was the best from a thermal perspective. The spacer frames based on aluminum, stainless steel, and a combination of stainless steel and plastic (TGI) did not provide adequate thermal insulation characteristics for usage in roof windows under the given climatic conditions, and condensation occurred on the glass surfaces.