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Don't be fooled by the NEW Building Regulations

Airtightness & Your Building Envelope
The new 2014 Building Regulations for England (April) and Wales (June) don’t change the reasonable limit for air permeability of 10m3/h/m2, nor do they change the requirement for pressure testing.

However, the air permeability rate used for calculating the TER has been reduced considerably to 5m3/h/m2.

This means all of your buildings will have to compensate for this difference by using better fabric insulation and/or other low energy measures.
Save 50% of the Heat Lost Through Your Building Envelope
As standards for thermal insulation have increased, so has the need to make sure you “Build Tight and Ventilate Right”. The need to eliminate unwanted air leakage paths means paying much greater attention to the details of how this is to be achieved to ensure sufficient ventilation for health. This can save up to 50% of the heat lost through your building envelope.
Air Leakage / Infiltration – v- Ventilation
Driven by wind speed and pressure, differences between inside and outside temperatures, and ‘the weather’ in general, this is the uncontrolled flow of air through gaps in the external envelope of your building. Ventilation is the deliberate removal and introduction of air, as when stale, moist air is replaced by fresh air.
Deciding how to do this requires careful consideration of how ‘airtight’ you want your building to be, and what type of ventilation system is most appropriate for this, e.g. window vents, power extraction, or MHRV (Mechanical Heat Recovery n& Ventilation). This in turn needs to be considered with the level to which, and how, the building is to be heated, as well as the costs involved.

The diagram gives an idea of the main 'air leakage points'.

See more at: SimplySelfBuild
Air Permeability of the External Fabric
Buildings must now be tested after completion to demonstrate that the external envelope of floors, walls, windows and ceiling (roof) surrounding the internal building volume do not exceed the design target for air leakage.

‘Fabric First’ has become the watchword for this. It involves choosing the right materials, construction details and methods to achieve these levels.

Timber Frame structures are one of the less ‘leaky’ forms of building – and easiest to make airtight.
Best Practice Timber Frame
As leading UK timber frame designers, engineers, manufacturers and builders Benfield ATT Group are ISO & IiP certified for quality and training to help you make the right choices for your projects.

As Chartered Building Consultants, Chartered Surveyors and LABC Partners we are also uniquely qualified and best placed to assist you with your design decisions, product selection, Building Regulation drawings, applications, and on site controls.
For More Information About How We Can Help YOU


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