Low Energy House » Airtight Houses - Airtight Barriers
Airtight Houses are an increasingly important part of a whole house approach to construction. Air pressure testing measures the permeability or airtight performance of the house to be assessed
Airtight Houses
Warm air leaking out through gaps in a house’s external envelope is a major cause of heat loss and, consequently, wasted energy. Improving airtightness in houses reduces the uncontrolled flow of air through gaps and cracks in the external fabric. With more stringent building regulations requiring better energy efficiency, airtightness is an increasingly important issue.
Airtight Houses - Design
A house’s design and the quality of its construction will have a major effect on the amount of air leakage. The issue of airtightness should be addressed at an early stage when the designer must identify where in the building envelope the air tight barrier will be located.The airtight barrier should form a continuous line around the house, passing through all the elements in the external fabric and separating heated and unheated spaces.
Constructing Airtight Barriers to Make Airtight Houses
The next and equally important step is to ensure these details are carried over into the construction phase. It is far simpler to design and build an airtight house than to carry our remedial measures later, in a draughty home. A continuous airtight barrier needs to be identified within the building envelope.
Programming the Building Work for Airtight Houses
Specifications must clearly address air tightness and subcontracts should include responsibility for carrying out the necessary sealing work. Building work must be carefully programmed so that each part of the airtight barrier is completed before following trades cover up the work. All works will need to be inspected as construction proceeds.
Once the building work is completed it may be difficult to examine the airtight barrier as it will often be covered by internal fixtures and finishes.
Inform the Householder About the Airtight Barrier
Having constructed an airtight house, it is important to make the householder aware of the fact. The householder needs to know the location of the airtight barrier in order not to compromise its effectiveness when carrying out future alterations. The efficiency of the heating and ventilation provided to the house depend on the airtight barrier being maintained.
When an airtight barrier is installed in the building envelope, controllable ventilation (preferably Mechanical Heat Recovery Ventilation - MHRV) is required in bathrooms, kitchens and utility rooms to remove water vapour and prevent damaging condensation
Low Energy House » Airtight Houses - Airtight Barriers
