Re: Sokli soojustamine
Postitatud: 19 Apr 2021, 13:54
https://www.constructioncanada.net/the- ... -must-die/xxx111 kirjutas: 19 Apr 2021, 13:54 Pole mitte mingit vahet kuidas kihti nimetada...
viewtopic.php?f=4&t=68133
Ma sellega lõpetan...
These conclusions resulted in regulation mandating the use of low-vapour permeance membranes in construction projects in the early 1950s. It was the birth of the “vapour barrier,” and the industry celebrated its solution to the moisture problem by lining walls with polyethylene plastic. Ostensibly the issue of peeling paint was resolved, or at least it seemed so.
Nonetheless, moisture problems persisted. Further, research in the mid-1980s suggested uncontrolled air infiltration, and not vapour diffusion, was the largest contributor to moisture accumulation in cavity spaces (Consult R.L. Quirouette’s 1985 technical report, “The difference between a vapour barrier and an air barrier.”). However, by that time the popularity of the now ubiquitous “6 mil poly”—backed by the Canadian General Standards Board (CAN/CGSB) 51.34, Vapor Barrier, Polyethylene Sheet for Use in Building Construction—inspired methods to seal the already familiar vapour barrier. The purpose was to turn it into an effective air barrier.
These attempts to seal the vapour barrier may be characterized as the genesis of the “air/vapour barrier,” both as a concept and term. Conceptually, the “air/vapour barrier” was a material purported to address both air infiltration and vapour diffusion issues. Its proponents believed by sealing the joints of polyethylene sheets, a dual-purpose material could emerge ascribing the additional properties of air infiltration control to the already popular “6 mil poly.” This popularity was perhaps responsible for its great appeal and wide adoption in the industry. As time passed, however, the idea of “sealing polyethylene” was quickly abandoned, and construction practitioners explored other materials to provide airtightness. It was clear polyethylene was not a sufficiently durable material to resist the effects of wind gusts and pressures. Moreover, this lack of durability was further undermined by the intrinsic difficulties associated with installing polyethelene in a continuous fashion.
Even if the concept of the polyethylene “air/vapour barrier” slowly faded, the term endured. Coincidentally, as time passed it also appeared as if the general understanding of the functions of these air and moisture control elements was further clouded by this conflated term. These once-distinct materials slowly transformed into abstract dotted lines everyone knew were required on construction details, but no one fully understood where or why.