What can we expect from Part L Building Regulations?

Part L Guide

So, Part L launches today (8th October) at the BRE to come into force in April 2014. So, what we can expect?

  • The Part L1A 6% improvement in TER is actually the same general level as the 8% consulted on. However compliance has been made easier for detached dwellings, to bring compliance in line with other dwelling types (so that the same specification could be used across a development), which reduced the overall improvement level to 6% on aggregate.
  • Non Domestic is a 9% improvement (with some associated adjustment of notional packages).
  • No improvements to L1B or L2B (only minor wording changes/clarifications).
  • No uplift to extensions or windows requirements.

A fabric target is to be introduced for domestic buildings based on the Fabric Energy Efficiency Standard (FEES) level less 15%. This new target sits alongside TER/DER compliance.

Fabric Energy Efficiency Standard is only affected  by building fabric U-values and areas (roofs, walls, floors, windows and doors); thermal bridging psi values and lengths; air tightness; thermal mass, and finally heat gains from solar, metabolic, lighting and appliances

So, what does this all mean for U-values?  Typically, if compliant by a largely fabric-lead approach,  it means that all new dwellings will have to achieve around these levels:

Wall 0.18 W/m2.K
Floor 0.13 W/m2.K
Roof 0.13 W/m2.K
Party Walls 0.00 W/m2.K
Air Tightness 5m³/m²/hr @ 50 Pa
Windows & doors 1.4 W/m2.K (G=0.63); 1.0 W/m2.K solid; 1.2 W/m2.K opaque.
Thermal Bridging Actual detail lengths x Psi values provided in SAP 2012.

Unfortunately transitional arrangements are not touched as these come under Building Act 1984, so expect vast numbers of building applications ‘banked’ in run up to April, so that builders can tie themselves into the current regulations, as long as they start work on a single plot within a year.

The Building Regulations should be available week commencing 21st October 2013 on www.planningportal.gov.uk

The BRE is creating a Beta version of SAP software to allow builders to explore what this means for them. This will eventually be available on www.2013ncm.bre.co.uk

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Jon Ducker is a qualified energy assessor working for Kingspan Insulation Ltd. He has an extensive knowledge of energy efficiency, renewable energy systems and sustainability in buildings with an expert knowledge of the relevant sections of buildings regulations and standards and their interactions with SAP. He provides authoritative advice regarding energy assessments for a wide range of public and private sector clients.

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