3.1 The following are key terms used in this document:
BCB means Building Control Body: a local authority or an approved inspector.
Building envelope in relation to a building means the walls, floor, roof, windows, doors, roof windows and roof-lights.
Commissioning means the advancement of a fixed building service following installation, replacement or alteration of the whole or part of the system, from the state of static completion to working order by testing and adjusting as necessary to ensure that the system as a whole uses no more fuel and power than is reasonable in the circumstances, without prejudice to the need to comply with health and safety requirements. For each system commissioning includes setting-to-work, regulation (that is testing and adjusting repetitively) to achieve the specified performance, the calibration, setting up and testing of the associated automatic control systems, and recording of the system settings and the performance test results that have been accepted as satisfactory.
Consequential improvements means those energy efficiency improvements required by regulation 28.
Controlled service or fitting means a service or fitting in relation to which Part G (sanitation, hot water safety and water efficiency), H (drainage and waste disposal), J (combustion appliances and fuel storage systems), L (conservation of fuel and power) or P (electrical safety) of Schedule 1 to the Building Regulations imposes a requirement.
Display window means an area of glazing, including glazed doors, intended for the display of products or services on sale within the building, positioned at the external perimeter of the building, at an access level and immediately adjacent to a pedestrian thoroughfare. There should be no permanent workspace within one glazing height of the perimeter. Glazing that extends beyond 3 m above such an access level is not part of a display window except:
a. where the products on display require a greater height of glazing;
b. in existing buildings, when replacing display windows that already extend to a greater height;
c. in cases of building work involving changes to the façade and glazing and requiring planning consent, where planners have discretion to require a greater height of glazing, e.g. to fit in with surrounding buildings or to match the character of the existing façade.
It is expected that display windows will be found in buildings in Planning Use Classes A1, A2, A3 and D2 as detailed in Table 1.
Table 1 Planning Use Classes
Dwelling means a self-contained unit, including a house or flat, designed to be used separately to accommodate a single household. (Rooms for residential purposes are not dwellings so this Approved Document L2B applies to work in such buildings).
Emergency escape lighting means that part of emergency lighting that provides illumination for the safety of people leaving an area or attempting to terminate a dangerous process before leaving an area.
Energy efficiency requirements means the requirements of regulations 23, 25A, 25B, 26, 28, 29 and 40 of, and Part L of Schedule 1 to, the Building Regulations.
In respect of existing buildings the applicable requirements consist of Part L and regulations 23 and 28.
energy performance certificate means a certificate which complies with regulation 7A of the Energy Performance of Buildings (England and Wales) Regulations 2012.
Fit-out work means that work needed to complete the internal layout and servicing of the building shell to meet the specific needs of an incoming occupier. The building shell is the structural and non-structural envelope of a building provided as a primary stage (usually for a speculative developer) for a subsequent project to fit out with internal accommodation works.
Fixed building services means any part of, or any controls associated with-
(a) fixed internal or external lighting systems (but not including emergency escape lighting or specialist process lighting);
(b) fixed systems for heating, hot water, air conditioning or mechanical ventilation; or
(c) any combination of systems of the kinds referred to in paragraph (a) or (b).
Major renovation means the renovation of a building where more than 25% of the surface area of the building envelope undergoes renovation.
High-usage entrance door means a door to an entrance primarily for the use of people that is expected to experience large traffic volumes, and where robustness and/or powered operation is the primary performance requirement. To qualify as a high-usage entrance door, the door should be equipped with automatic closers and, except where operational requirements preclude, be protected by a lobby.
Principal works means the work necessary to achieve the client’s purposes in extending the building and/or increasing the installed capacity of any fixed building services. The value of the principal works is the basis for determining a reasonable provision of consequential improvements.
Renovation in relation to a thermal element means the provision of a new layer in the thermal element (other than where that new layer is provided solely as a means of repair to a flat roof) or the replacement of an existing layer, but excludes decorative finishes, and ‘renovate’ shall be construed accordingly.
Simple payback means the amount of time it will take to recover the initial investment through energy savings, and is calculated by dividing the marginal additional cost of implementing an energy efficiency measure by the value of the annual energy savings achieved by that measure taking no account of VAT. When making this calculation, the following guidance should be used:
a. The marginal additional cost is the additional cost (materials and labour) of incorporating (e.g.) additional insulation, not the whole cost of the work.
b. The cost of implementing the measure should be based on prices current at the date the proposals are made known to the BCB and be confirmed in a report signed by a suitably qualified person.
c. The annual energy savings should be estimated using an energy calculation tool approved by the Secretary of State pursuant to regulation 24.
d. For the purposes of this Approved Document, the energy prices that are current at the time of the application to building control should be used when evaluating the annual energy savings. Current energy prices can be obtained from the DECC website¹.
Thermal element is defined in regulation 2(3) of the Building Regulations as follows:
(3) In these Regulations ‘thermal element’ means a wall, floor or roof (but does not include windows, doors, roof windows or roof-lights) which separates a thermally conditioned part of the building (‘the conditioned space’) from:
a. the external environment (including the ground); or
b. in the case of floors and walls, another part of the building which is:
ii. an extension falling within class VII in Schedule 2; or
iii. where this paragraph applies, conditioned to a different temperature, and includes all parts of the element between the surface bounding the conditioned space and the external environment or other part of the building as the case may be.
(4) Paragraph (3)(b)(iii) applies only to a building which is not a dwelling, where the other part of the building is used for a purpose which is not similar or identical to the purpose for which the conditioned space is used.
Note that this definition encompasses the walls and floor of a swimming pool basin where this is part of an existing building.
Total useful floor area is the total area of all enclosed spaces measured to the internal face of the external walls, that is to say it is the gross floor area as measured in accordance with the guidance issued to surveyors by the RICS. In this convention:
a. the area of sloping surfaces such as staircases, galleries, raked auditoria, and tiered terraces should be taken as their area on plan; and
b. areas that are not enclosed such as open floors, covered ways and balconies are excluded.
This equates to the gross floor area as measured in accordance with the guidance issued to surveyors by the RICS.
Types of work covered by this Approved Document
3.2 This Approved Document is intended to give guidance on what, in ordinary circumstances, may be considered reasonable provision for compliance with the requirements of regulations 23, 28 and 40 of, and Part L of Schedule 1 to, the Building Regulations when carrying out work on existing buildings that are not dwellings. In addition it gives guidance on compliance with regulations 25A, 27, 43 and 44 of the Building Regulations and 20(1), 20(2) and 20(6) of the Approved Inspectors Regulations 2010.
It should be noted that dwellings are defined as self-contained units. Rooms for residential purposes are not dwellings, and so this Approved Document applies to them.
3.3 In particular, this Approved Document gives guidance on compliance with the energy efficiency requirements where the following occurs:
a. the construction of an extension (see paragraphs 4.1 to 4.13);
b. a material change of use or a change to the building’s energy status (paragraphs 4.15 to 4.21);
c. the provision or extension of a controlled fitting or controlled service (see paragraphs 4.22 to 4.48;
d. the replacement or renovation of a thermal element (Section 5);
e. the major renovation of a building;
f. consequential improvements (Section 6).
3.4 For certain types of work in relation to an existing building, it may be more appropriate to use the guidance from the other Approved Documents L, or to follow only a limited amount of the guidance in this Approved Document. The following sub-paragraphs identify some of the circumstances in which this might be appropriate:
a. For first fit-out works in buildings such as shell and core office buildings or business park units, the guidance in Approved Document L2A (new non-domestic buildings) covering first fit-out should be followed (but note that the appropriate guidance for any subsequent fit-out works is contained in this Approved Document).
b. Large extensions (as defined in paragraph 4.2) should be carried out in accordance with the guidance in Approved Document L2A. However, regulation 28 (consequential improvements to energy performance) may apply, in which case the guidance in relation to that regulation set out in this Approved Document would be relevant.
c. Modular and portable buildings: where the work involves the construction of subassemblies that have been obtained from a centrally held stock or from the disassembly or relocation of such buildings at other premises, the guidance in Approved Document L2A should be followed but regulation 28 (consequential improvements to energy performance) may also apply if the work was to extend an existing building. In that context, the guidance in relation to that regulation as set out in this Approved Document would be relevant.
Note that erecting a separate unit on a site with an existing building is not extending that existing building, but is the creation of a new building, unless the new unit is to be permanently linked to the existing building.
d. Where the work involves a building that either before the work or after the work is completed contains one or more dwellings, the guidance in Approved Document L1B would apply to each dwelling.
It should be noted that dwellings are defined as self-contained units. Rooms for residential purposes are not dwellings, and so this Approved Document applies to them.
Buildings exempt from the energy efficiency requirements
3.5 Building work in most existing buildings other than dwellings will need to comply with the energy efficiency requirements of the Building Regulations where the buildings are roofed constructions having walls and use energy to condition the indoor climate. Regulation 21 of the Regulations, however, grants an exemption from compliance with the energy efficiency requirements to certain classes of buildings
a. buildings which are:
i. listed in accordance with section 1 of the Planning (Listed Buildings and Conservation Areas) Act 1990;
ii. in a conservation area designated in accordance with section 69 of that Act; or
iii. included in the schedule of monuments maintained under section 1 of the Ancient Monuments and Archaeological Areas Act 1979,
where compliance with the energy efficiency requirements would unacceptably alter their character or appearance;
b. buildings which are used primarily or solely as places of worship;
c. temporary buildings with a planned time of use of 2 years or less, industrial sites, workshops and non-residential agricultural buildings with low energy demand;
d. stand-alone buildings other than dwellings with a total useful floor area of less than 50 m²;
e. carports, covered yards, covered ways and some conservatories or porches attached to existing buildings. Guidance on these is given at paragraphs 3.21 and 3.22 below.
3.6 Special considerations apply to certain classes of non-exempt building. These building types are:
a. historic buildings and buildings used primarily or solely as places of worship; the considerations that apply to such existing buildings are given in paragraphs 3.9 to 3.14;
b. buildings with low energy demand; the guidance specific to such buildings is given in paragraphs 3.15 to 3.20;
c. modular and portable buildings; for the construction of such buildings with a planned service life of more than 2 years at one or more locations, the guidance in Approved Document L2A should be followed. Any changes to the building fabric or fixed building services should comply with this Approved Document.
Historic and traditional buildings which may have an exemption
3.7 As mentioned above in paragraph 3.5 the following classes of buildings have an exemption from the energy efficiency requirements where compliance would unacceptably alter the character or appearance of the buildings:
a. listed buildings;
b. buildings in conservation areas; and
c. scheduled ancient monuments.
Historic and traditional buildings where special considerations may apply
3.8 There are three further classes of buildings where special considerations in making reasonable provision for the conservation of fuel or power may apply:
a. buildings which are of architectural and historical interest and which are referred to as a material consideration in a local authority’s development plan or local development framework;
b. buildings which are of architectural and historical interest within national parks, areas of outstanding natural beauty, registered historic parks and gardens, registered battlefields, the curtilages of scheduled ancient monuments and world heritage sites;
c. buildings of traditional construction with permeable fabric that both absorbs and readily allows the evaporation of moisture.
3.9 When undertaking work on or in connection with a building that falls within one of the classes listed above, the aim should be to improve energy efficiency as far as is reasonably practical. The work should not prejudice the character of the host building or increase the risk of long-term deterioration of the building fabric or fittings.
3.10 The guidance given by English Heritage² should be taken into account in determining appropriate energy performance standards for building work in historic buildings.
In addition English Heritage has produced detailed technical guidance on how to implement specific energy efficiency measures. (See list of available guidance documents at http://www.english-heritage.org.uk/professional/advice/advice-by-topic/climate-change/energy-efficiency/.)
3.11 In general, new extensions to historic or traditional buildings should comply with the standards of energy efficiency as set out in this Approved Document. The only exception would be where there is a particular need to match the external appearance or character of the extension to that of the host building.
3.12 Particular issues relating to work in historic buildings that warrant sympathetic treatment and where advice from others could therefore be beneficial include:
a. restoring the historic character of a building that has been subject to previous inappropriate alteration, e.g. replacement windows, doors and rooflights;
b. rebuilding a former historic building (e.g. following a fire or filling a gap site in a terrace);
c. making provisions enabling the fabric of historic buildings to ‘breathe’ to control moisture and potential long-term decay problems.
3.13 In assessing reasonable provision for energy efficiency improvements for historic buildings of the sort described in paragraphs 3.7 and 3.8, it is important that the BCB takes into account the advice of the local authority’s conservation officer. The views of the conservation officer are particularly important where building work requires planning permission and/or listed building consent.
Places of worship
3.14 For the purposes of the energy efficiency requirements, places of worship are taken to mean those buildings or parts of a building that are used for formal public worship, including adjoining spaces whose function is directly linked to that use. Such parts of buildings of this type often have traditional, religious or cultural constraints that mean that compliance with the energy efficiency requirements would not be possible. Other parts of the building that are designed to be used separately, such as offices, catering facilities, day centres and meeting halls are not exempt.
Industrial sites, workshops and non residential agricultural buildings with low energy demand
3.15 In relation to this category of exempt building, the low energy demand relates only to the energy used by fixed heating or cooling systems, NOT to energy required for or created by process needs. The following are examples of buildings in the above categories that are low energy demand:
a. buildings or parts of buildings where the space is not generally heated, other than by process heat, or cooled;
b. buildings or parts of buildings that require heating or cooling only for short periods each year, such as during critical periods in the production cycle (e.g. plant germination, egg hatching) or in very severe weather conditions.
3.16 Industrial sites, workshops and non-residential agricultural buildings are only exempt if they meet the low energy demand criterion. If not exempt, such buildings must comply with energy efficiency requirements. Similarly, other buildings (e.g. some types of warehouse) may have low energy demand but are not exempt because they do not fall into one of the above categories.
Non-exempt buildings with low energy demand
3.17 For the purposes of this Approved Document, non-exempt buildings with low energy demand are taken to be those buildings or parts thereof where:
a. fixed building services are used to heat or cool only a localised area rather than the entire enclosed volume of the space concerned (e.g. localised radiant heaters at a workstation in a generally unheated space); or
b. fixed building services are used to heat spaces in the building to temperatures substantially lower than those normally provided for human comfort (e.g. to provide condensation or frost protection in a warehouse).
3.18 In such situations, it is not reasonable to expect the entire building envelope to be insulated to the standard expected for more typical buildings. Therefore, if an existing building with low levels of heating is extended or parts of the fabric renovated, the new or renovated building envelope should be insulated only to a degree that is reasonable in the particular case. If some general heating is provided (case b above), then it would be reasonable that no part of the opaque fabric had a U-value worse than 0.7 W/m².K. In addition, reasonable provision would be for every fixed building service that is installed to meet the energy efficiency standards set out in the Non-Domestic Building Services Compliance Guide³.
3.19 If a part of a building with low energy demand is partitioned off and heated normally (e.g. an office area in an unheated warehouse), the separately heated area should be treated as a separate ‘building’ and the normal procedures for demonstrating compliance should be followed in respect of the enclosure.
3.20 If a building with low energy demand subsequently changes such that the space is generally conditioned, then this is likely to involve the initial provision or an increase in the installed capacity of a fixed building service. Such activities may fall within regulation 28 which would require the building envelope to be upgraded and consequential improvements to be made (see the guidance in Section 6 of this Approved Document). Alternatively, if the building shell was designed as a building with low energy demand and the first occupier of the building wanted to install (e.g.) heating, this would be a first fit-out works, and Approved Document L2A would apply.
Conservatories and porches
3.21 Regulation 21 of the Building Regulations exempts some conservatory and porch extensions from the energy efficiency requirements. The exemption applies only to conservatories or porches:
- which are at ground level;
- where the floor area is less than 30m²;
- where the glazing complies with Parts K 4, K 5.1, K 5.2, K 5.3 and K 5.4 of Schedule 1;
- where the existing walls, doors and windows which separate the conservatory from the building are retained or, if removed, are replaced by walls, windows and doors which meet the energy efficiency requirements; and
- where the heating system of the building is not extended into the conservatory or porch.
3.22 Where any conservatory or porch does not meet all the requirements in the preceding paragraph, it is not exempt and must comply with the relevant energy efficiency requirements (see paragraphs 4.12 and 4.13 below).
² Energy Efficiency and Historic Buildings, English Heritage, 2011 www.english-heritage.org.uk/publications/energy-efficiency-historic-buildings-ptl/
³ Non-Domestic Building Services Compliance Guide, DCLG, 2013.
Notification of work covered by the energy efficiency requirements
3.23 In most instances, in order to comply with the Building Regulations it will be necessary to notify a BCB before the work starts. If you choose to use the local authority this must be by deposit of full plans. There is no set procedure where the BCB is an Approved Inspector provided it has been notified at least 5 days before work starting.
3.24 In certain situations, however, other procedures apply:
a. Where the work is being carried out by a person registered with a relevant competent person self-certification scheme listed in Schedule 3 to the Building Regulations, no advance notification to the BCB is needed (see paragraphs 3.25 to 3.28);
b. Where the work involves an emergency repair, e.g. to a failed boiler or a leaking hot water cylinder, in accordance with regulation 12(8) of the Building Regulations there is no need to delay making the repair in order to make an advance notification to the BCB. However, in such cases it will still be necessary for the work to comply with the relevant requirements and to give a notice to the BCB at the earliest opportunity, unless an installer registered under an appropriate competent person scheme carries out the work. A completion certificate can then be issued in the normal way;
c. Where the work is of a minor nature as described in the schedule of non-notifiable work (Schedule 4 to the Building Regulations), the work must still comply with the relevant requirements but need not be notified to the BCB (see paragraphs 3.29 and 3.30).
Competent person self-certification schemes
3.25 It is not necessary to notify a BCB in advance of work which is to be carried out by a person registered with a relevant competent person self-certification scheme listed in Schedule 3 to the Building Regulations. In order to join such a scheme, a person must demonstrate competence to carry out the type of work the scheme covers, and also the ability to comply with all relevant requirements in the Building Regulations.
3.26 Where work is carried out by a person registered with a competent person scheme, regulation 20 of the Building Regulations and regulation 20(1) of the Approved Inspectors Regulations require that the occupier of the building be given, within 30 days of the completion of the work, a certificate confirming that the work complies fully with all applicable building regulation requirements. There is also a requirement to give the BCB a notice of the work carried out, again within 30 days of the completion of the work. These certificates and notices are usually made available through the scheme operator.
3.27 BCBs are authorised to accept these certificates and notices as evidence of compliance with the requirements of the Building Regulations. Local authority inspection and enforcement powers remain unaffected, although they are normally used only in response to a complaint that work does not comply.
3.28 A list of authorised self-certification schemes and the types of work for which they are authorised can be found at www.communities.gov.uk.
Work which need not be notified
3.29 Schedule 4 to the Building Regulations sets out types of work where there is no requirement to notify a BCB that work is to be carried out. These types of work are mainly of a minor nature where there is no significant risk to health, safety or energy efficiency. Note that the health, safety and energy efficiency requirements continue to apply to these types of work, and that only the need to notify a BCB has been removed. In addition, where only non-notifiable work is carried out by a member of a competent person self-certification scheme there is no requirement for a certificate of building regulations compliance to be given to the occupier or the BCB.
3.30 The types of non-notifiable work in Schedule 4 relevant to the energy efficiency requirements of the Regulations are:
a. In a heating, hot water service, ventilation or air-conditioning system, the replacement any part which is not a combustion appliance (such as a radiator, valve or pump) or the addition of an output device (such as a radiator or fan) or the addition of a control device (such as a thermostatic radiator valve). However, the work will remain notifiable whenever commissioning is possible and necessary to enable a reasonable use of fuel and power.
b. The installation of a stand-alone, self-contained fixed heating, hot water, ventilation or air-conditioning service. Such services must consist only of a single appliance and any associated controls, and must not be connected to any other fixed building service. Examples of non-notifiable services would be a fixed electric heater, a mechanical extractor fan in a kitchen or bathroom, and a room air-conditioning unit. However, if any of the following apply, the work will remain notifiable building work:
i. the service is a combustion appliance; or
ii. commissioning is possible and would affect the service’s energy efficiency (see paragraphs 4.36 to 4.48); or
iii. in the case of a ventilation appliance, the appliance is installed in a room containing a natural draught open-flued combustion appliance or service, such as a gas fire which uses a chimney as its flue.
c. Installation of thermal insulation in a roof space or loft space where this is the only work carried out and the work is carried out voluntarily and not in order to comply with any requirement in the Building Regulations.
Materials and workmanship
3.31 Any building work which is subject to the requirements imposed by schedule 1 to the Building Regulations shall be carried out in accordance with regulation 7. Guidance on meeting these requirements on materials and workmanship is contained in the Approved Document to support regulation 7.
3.32 Building Regulations are made for specific purposes, primarily the health and safety, welfare and convenience of people and for energy conservation. Standards and other technical specifications may provide relevant guidance to the extent that they relate to these considerations. However, they may also address other aspects of performance or matters which, although they relate to health and safety etc., are not covered by the Building Regulations.
3.33 When an Approved Document makes reference to a named standard, the relevant version of the standard to which it refers is the one listed at the end of the publication. However, if this version has been revised or updated by the issuing standards body, the new version may be used as a source of guidance provided it continues to address the relevant requirements of the Regulations.
The Workplace (Health, Safety and Welfare) Regulations 1992
3.34 The Workplace (Health, Safety and Welfare) Regulations 1992, as amended, apply to the common parts of flats and similar buildings if people such as cleaners, wardens and caretakers are employed to work in these common parts. These Regulations contain some requirements which affect building design. The main requirements are now covered by the Building Regulations, but for further information see Workplace health, safety and welfare, Workplace (Health, Safety and Welfare) Regulations 1992, Approved Code of Practice and guidance, HSE publication L24, 1996.