Durability of self-adhesive tapes for exterior air barrier applications: a laboratory investigation

摘要

In timber frame construction in Europe, air barrier systems are typically realised at the interior side of the building envelope. Yet, in some applications such as renovation projects, it can be easier to provide the air barrier layer at the exterior. An exterior air barrier system, typically board materials in which the joints are sealed with tape, needs to withstand severe outdoor weather conditions and maintain pre-defined air permeability values. The aim of the present article is to investigate the impact of severe climatic conditions on the airtightness of typical taped joints. The airtightness of 32 wood fibre cement board samples has been investigated. Each specimen has a 2 mm wide joint. Two different kinds of commercially available tapes were used to seal these joints. Airtightness of all specimens has been tested before and after accelerated ageing procedures that mimic real exterior climate conditions. Three different ageing protocols were selected: (1) temperature cycles, (2) temperature, rain and frost cycles and (3) UV exposure alternate with high humid conditions. The present paper discusses the durability of the two tapes by comparing the air permeability of the specimens before and after accelerated ageing exposure. The results indicate that for both tapes tested the impact of the three artificial ageing methods on the air permeability is limited (increment less than 2 x 10(-5) m(3)/m/h/Pa).