Part L

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– Residential Homeowner, Mr Tomlinson

New changes to Part L Building Regulations effective from April 2014

The 2013 revisions of Part L relating to Conservation of Fuel and Power have now been published by the Department for Communities and Local Government (DCLG). It has also updated versions of the Domestic and Non Domestic Building Services Compliance Guides.

  • Under the Approved Document L2A 2013 (New buildings other than dwellings),the specification has been strengthened to deliver 9% carbon dioxide saving across the new non domestic building mix in relation to Part L 2010.A summary of the Part L 2013 notional buildings is published as Table 5 in the Approved Document with the full detail in the National calculation methodology modelling guide.
  • If the actual building is constructed entirely to the notional building specification it will meet the carbon dioxide targets and the limiting fabric and building services parameters However, developers are free to vary the specification provided overall level of carbon dioxide is achieved or bettered.
  • The document consolidates the amendments made in December 2012 regarding the feasibility of high efficiency alternative systems to be taken into account before construction commences. The guidance for insulation of circulation pipes within communal spaces is also given greater prominence.The document is in a new style format and an index has been introduced.
  • A change in Regulation 26A in Approved Document L1A (New Dwellings), is the requirement for new dwellings to achieve or better a fabric energy efficiency target in addition to the carbon dioxide target.
  • The specification has been strengthened to deliver 6% carbon dioxide saving across the new home build mix relative to Part L 2010. A summary of the Part L 2013 notional dwelling is published as Table 4 in the Approved Document with the full detail in Standard Assessment Procedure 2012 Appendix R.

The Welsh Government has now provided details of the new Part L. This is the first time Part L is being split in two with one version to cover England and another version for Wales. The Welsh updates were only announced recently and include the following variations from the above English version:

  • For the new-build domestic sector, there aren’t too many variations to be concerned with as the majority of requirements and compliance options are the same as the English version.
  • The Welsh Part L comes into effect on 31st July 2014 with the same transitional arrangements. This means that, if you appoint Act and we give an initial notice for the building works before this date you can build to Part L 2010 providing you make a start on the work within twelve months.
  • The new Target Emission Rate is being calculated in a completely new way using a technique called the ‘Elemental Specification’. This is a published specification which, if followed, will meet compliance with the new Part L.
  • The Elemental Specification is going to be the same for both England and Wales, which means the Target Emission Rate shown on SAP will be the same regardless of country. There had been concerns among builders who work along the border towns that they would need to develop more efficient specifications for their Welsh developments.
  • Another big change is that all maximum U Values in Wales are being lowered for the SAP calculation. This means you’ll need to include higher levels of insulation to ensure you meet these enhanced targets. The new Values to newly built dwellings will be:
  • For heat loss floors, the U Value is reduced from 0.25 to 0.18
  • For heat loss walls, the U Value is reduced from 0.30 to 0.21
  • For roofs, the U Value is reduced from 0.2 to 0.15
  • For glazing, the U Value is reduced from 2.00 to 1.60
  • In England, all U Values have been left at the 2010 standard, and instead a Target Fabric Energy Efficiency (TFEE) has been imposed that will lead to the use of lower U Values in order to gain compliance.
  • Because Wales has opted for these lower U value requirements, there is not going to be a TFEE requirement as well. (But you will still have to meet the Target Emission Rate).

The full set of Welsh building regulations for Part L, including the new Elemental Recipe, are available from the Welsh Government website.

If you need any further advice regarding these Building Regulation changes, please contact a member of our technical team on 0845 077 9559.