Approved Document Part L for Wales

June 6, 2014 9:38 am

Approved Document Part L for Wales issued and implementation date set for 31st July 2014

New Building Regulation Approved Document Guidance has been produced by the Welsh Government that covers energy efficiency of new and existing buildings.  This follows the recent implementation of the Building Regulations Part L for England.  Wales have been delegated independent powers to produce their own Building Regulation Standards and the 2014 Part L is the first time different Approved Documents have been issued for use in England and Wales.

The main changes within the Welsh Part L are that new build dwellings should be improved to deliver an 8% reduction in CO2 Emissions relative to Part L 2010, a new Energy Efficiency standard has been introduced to strengthen the process of ‘Fabric First’ when carbon dioxide savings are applied to new build dwellings, and the building fabric thermal performance standards have been strengthen with big improvements to U-values.

For domestic extensions the worse acceptable fabric U-values for thermal elements have been improved to match the revised new build standard and these are likely to push wall thickness to around 350mm overall width with 150mm cavity wall insulation being used.

Consequential improvements have been introduced to all domestic extensions.  Consequential improvements describe additional energy efficiency improvements that should be undertaken where an existing dwelling is extended and is aimed at improving the energy efficiency of the existing housing stock.  Where an extension has a floor area less than 10m2 loft insulation would be required to the existing building so that a minimum of 250mm thick loft insulation is provided.  For extensions over 10 m2 cavity wall insulation and insulation to hot water cylinders should also be applied.  If the existing dwelling has these features no Consequential improvements would be required.

New build non-domestic buildings should be improved to deliver an 20% reduction in CO2 Emissions relative to Part L 2010, this is significantly better than the standards required within England.  This carbon dioxide reduction is likely to result in renewable energy systems being required on most new build developments as it is increasingly difficult to achieve these savings through improvements to the buildings thermal performance and building services.

U-value standards for non-domestic extensions have been improved within the 2014 Part L2B and Consequential Improvements have been introduced for all extensions to existing buildings.  These consequential improvements can range from thermal upgrades to the existing building through to improvements in the existing buildings heating, cooling, hot water, ventilation of lighting systems.  These improvements should equate to 10% of the build cost and can pose a significant risk to projects if people are unaware of the requirement.

Further guidance can be found at the Welsh Governments Web site:

For more information or if you would like a CPD update on the recent changes to Part L please contact Joe Campion on 01780 460464.

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