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Airtight attic systems

What is Airtightness?

  • Airtightness is the control of air leakage, i.e., the elimination of unwanted draughts through the external fabric of the building envelope.  
  • This may be achieved by the correct and proper installation of a vapour check or vapour barrier. Consequently, condensation, mould, rot, damp and structural damage are also eliminated.  
  • This ensures a more viable structure, an insulation layer that can perform properly as it is now protected against penetrating moisture reducing the amount of energy-in-use in the building and CO2 emissions.  While ventilation is intended, air leakage is not.  It is desirable and necessary to have controlled ventilation for healthy comfortable buildings

Draughty leaky house/Build tight ventilate right house 

Why is Airtightness Important?

  • Sustainable design and construction to achieve low energy, PassivHaus and zero carbon homes are now at the forefront of the building and planning process.
  • Codes and standards are in place which aim to reduce carbon emissions and create homes that are healthier and more sustainable.
  • The only way to achieve PassivHaus, low carbon and nearly zero energy building is to ensure a high level of airtightness is attained.
  • That means designing and installing a continuous seal around the internal fabric of the external envelope to eliminate unwanted draughts. Airtightness - Preventing uncontrolled air movement
  • Once the airtight vapour check is in place and sealed with flexible and durable tapes, seals and glues, it ensures that the insulation functions to its optimum performance, saving energy and drastically reducing carbon emissions for the lifetime of the building.
  • Airtightness maintains the same indoor temperature saving energy costs on your heating with perfect insulation. Airtight building insulation ensures that energy is kept within your home, rather than being wasted by escaping into the atmosphere.

What is an 'Intelligent' Airtight System?

pro clima are the pioneers 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 (see Figure 4) and will resist the diffusion of vapour from the internal fabric of the building into the insulating layer.  However, in summer  (see Figure 5) pro clima membranes, INTELLO PLUS and DB+, may become more vapour
    pro clima airtightness system prevents uncontrolled air infiltrationopen.  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.  The membrane always remains airtight

diffusion tight membrane and vapour open

Why is Windtightness Important?

  • Weathertightness enables a building to withstand the natural weather elements, both Watertightness and windtightness fall into this category.
  • A leaky building allows water and moisture to infiltrate the building envelope where it becomes trapped, this leads to mould and rot within the construction.
  • Wind movement can also create issues with air forced from the outside into the insulation layer allowing the water to be transported into the construction through convection. 

Windtightness