Introduction

This guide is intended to help house builders and designers understand what the October 2010 changes to Approved Document L1A (Conservation of fuel and power in new dwellings) mean.

The new ADL1A builds on the process for demonstrating compliance established by previous versions.  Together with the reduction in annual carbon dioxide (CO2) emissions there are also technical changes including an allowance for party wall heat loss.

The guide gives examples of some typical homes, outlining a combination of measures needed to comply with ADL1A 2010.  The intention is to give a broad understanding of the specification that may need to be incorporated, as a starting point for detailed design.  These are only representative approaches to compliance and the intention of ADL1A 2010 is very much to allow builders flexibility in how they might choose to comply with the new requirements.

The examples used are based on typical homes on typical developments, from information gathered by NHBC about the homes being built today.  These examples were used by the Zero Carbon Hub (ZCH) for their work on the Fabric Energy Efficiency Standard (FEES) and the definition of zero carbon homes that will apply from 2016.

This is only a general guide and there is no obligation to adopt any of the typical approaches given.  You should always check with the Building Control Body that your proposals comply with the requirements of the Building Regulations.  As part of your Building Regulations application you will have to provide a CO2 emissions rate calculation for your new home using the Government’s Standard Assessment Procedure (SAP 2009) before construction work commences and again on completion.  You will also need to comply with NHBC Standards and planning requirements, etc.
 

Criteria

The five criteria for establishing compliance are:

Criterion 1

Achieving the Target Emission Rate; the predicted annual CO2 emission rate of the new home is less than the target calculated using SAP 2009 and has a minimum overall improvement of 25% relative to 2006 standards.

Criterion 2

Limits on design flexibility; the thermal performance of building elements and the building services efficiencies do not fall below minimum values.

Criterion 3

Limiting the effects of solar gains in summer; the building does not suffer from excessive summer solar heat gains.

Criterion 4

Building performance consistent with Design Emission Rate; the performance of the building and services are verified through testing and commissioning.

Criterion 5

Provisions for energy efficient operation of the dwelling; information is provided to the home occupier to enable them to operate their new home efficiently.
For more detailed information a full version of Approved Document L1A 2010 can be downloaded from: www.planningportal.gov.uk

Guide

The guide is intended to be used as a starting point for discussions with advisers and suppliers and it follows a logical sequence of questions that might be asked at the outset of a
new project:

• What is current practice?
• What choices are available now?
• What is the detailed specification for each choice?
• What will this look like as a construction?

For each home type four possible alternatives are illustrated on the same page to aid comparison between approaches.

There will be numerous routes to compliance and house builders will no doubt develop their own cost-effective strategies to meet the requirements.  The options proposed are considered to be helpful illustrations of typical approaches but should not be regarded as definitive.

Towards the end of the guide typical construction build-ups are illustrated to show the likely wall thicknesses and the types of insulating materials used; along with floor and roof constructions.

At the end of the guide we discuss the likely changes that are on the horizon for the next revision of ADL1A.  This is by no means essential reading but it will be useful for house builders preparing to meet the higher standards expected to apply from 2013 and may influence some decisions now.  For instance it will help to inform decisions as to whether to embrace a new construction or technology now in order that the implications are fully understood when it becomes a necessity.