Moisture in buildings

How can moisture accumulate within building elements?

Unanticipated moisture may be present in buildings; perhaps as a result of extremely adverse conditions during the building stage (e.g. the timber / insulation gets damp) due to flanking, diffusion directly through the membrane or air leakage (e.g. convection). Using an ‘intelligent’ Pro Clima vapour check ensures that this moisture can dry as quickly as possible due to its unique diffusion properties. Conventional vapour barriers remain vapour tight under all conditions which may lead to damaging moisture build-up. The Pro Clima system offers superior protection against even extreme unforeseen circumstances.

Diagram demonstrating the importance of airtightness
Research shows that under normal winter conditions around 0.5g of moisture is able to penetrate a gap free vapour check/barrier by diffusion. The diagram shows with a 1mm tear over a 1 square metre area in the vapour check/barrier as much as 800g of moisture can be transferred into the structure per square metre length by air leakage (convection) – a reduction in performance by 1,600 times! Measurements were taken at an air temperature difference of +20C (68F) indoors and -10C (14F) outdoors, a pressure difference of 20 Pa (equivalent to wind force 2-3) using conventional, fibrous insulating material. Such a small tear can reduce the diffusion resistance by a factor of 1,600.

Measurement carried out by: Institut fur Bauphysik, Stuttgart.

What is an ‘Intelligent’ airtight system?

Pro Clima are innovators and market leaders of an ‘Intelligent’ airtight system. This differs greatly from conventional vapour barriers and vapour checks. The technology used in Pro Clima membranes, Intello Plus and DB+, ensures membranes may become more vapour ‘diffusion open’ when required. This means that they have the ability to alter their vapour diffusion resistance depending on the average relative humidity surrounding the vapour check. In winter the membrane remains diffusion tight and will resist the diffusion of vapour from the internal fabric of the building into the insulated layer. However, in summer Pro Clima’s membranes, Intello Plus and DB+, may become more vapour open. This allows any moisture which may be trapped in the insulated fabric of the building to back dry to the inside of the house, something a conventional vapour barrier/check cannot do. This ensures a very high level of safety from structural damage due to moisture accumulation over seasonal periods. An intelligent membrane facilitates significantly more drying compared to a vapour barrier/check.

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