Paul Meadows, Director at Salus Approved Inspectors, gives a technical summary on changes to the latest Building Regulations, including a series of Q & A from Ministry of Housing, Communities and Local Government (MHCLG).
Permitted Development changes and effects upon Building Regulations
By making use of existing buildings, the government hopes that by introducing permitted development rights there will be an uptake by developers to increase the housing supply. In support of this initiative ministers want to ensure that fire safety measures in the provision of additional dwellings are not compromised and the requirements of the building regulations are met. A circular has therefore been released by MHCLG to reinforce the requirements, given there have been several changes to part B and Regulation 7 over the last few years, post Grenfell. The circular requirements apply to building works within England.
Building Regulations 2010 – as amended
Whilst as Building Control Bodies we all consider each application on the merits of the proposals, it is likely that where additional storeys are added to an existing building, some work on the original part of the building will be necessary.
The nature of the measures necessary may swell not set out specifically each example of how to meet a requirement.
We have therefore also attached a selection of questions asked to MHCLG regarding application of the regulations to existing buildings.
The regulations pose a series of questions that must be considered, the first being whether the work is deemed to be controlled and notifiable.
It seems difficult to envisage a situation where the addition of new storeys to a building would not be notifiable building work, so the following questions then arise;
Regulation 4(1) – Does the work itself comply with the applicable requirements.
Each requirement should be considered in turn and all of them must be met. In many cases, the existing building will need to be modified to allow the additional storeys to comply.
For example, where escape routes from the new accommodation pass through the existing building, the full extent of the escape route should be addressed to ensure it satisfies B1.
Regulation 4(3) – Does the work result in the building, as a whole, being no less compliant
Each requirement should be considered and where necessary the existing building should be modified.
For instance, the increased height of the building may result in a need to address requirement A3 -Disproportionate Collapse, B3 Internal fire precautions for the entire building. Etc
Regulations 5 & 6 – Are there requirements relating to material change of use
The regulations provide that where a change of use takes place, work must be carried out so that the building complies with the applicable requirements listed in regulation 6 (this includes a change to the number of dwellings in a building).
Attention is drawn to regulations 6(2)(a) and 6(3) which relate to external wall construction.
Regulation 28 – Are there consequential requirements
Where the existing building has a useful floor area over 1000m2 consequential improvements to the energy performance may be required. This requirement applies to the entire building and will therefore capture many medium to large sized buildings.
Manual to the Building Regulations
The Manual to the Building Regulations provides detailed advice on many of the matters set out the circular.
Paragraph A20 provides a useful summary of the provisions for material change of use.
Where an additional storey or storeys changes the consequence class of a building during the course of building work, it is likely to be less satisfactory in relation to A3 after the work, because the change in Consequence Class brings with it a requirement for a higher level of robustness measures for the building.
The Building Control Alliance has published advice on this issue in BCA Technical Guidance Note 21
“REQUIREMENT A3 – DISPROPORTIONATE COLLAPSE”
A previous circular letter of 26 May 2020 addresses the provision of sprinklers in extensions which is equally relevant to upward extensions.
External wall construction
Below is a series of Answers by MHCLG to a number of frequently asked questions related to the application of regulation 7(2) questions.
How do the Building (Amendment) Regulations 2018 affect buildings undergoing remediation?
The ban on the use of combustible materials in the external walls of buildings has been implemented through amendments to the Building Regulations 2010. The ban is set out in Statutory Instrument 2018/1230 and applies to any building work (as defined in regulation 3) carried out in or on a building in scope of the ban (as defined in regulation 7(4)). Please note the scope of the ban is under a consultation to further reduce the height from 18m to 11m.
The requirement is that building work on such buildings must be carried out so that only materials which achieve European Classification A1 or A2-s1, d0 become part of an external wall or specified attachment (as defined in regulation 2) unless covered by one of the exemptions in the regulations.
This means that materials which are already part of the external wall, or are existing specified attachments, and are not being replaced are not covered by the ban (unless there is a change of use – see question 2). However, during this process care must be taken to ensure that the building is no less compliant in relation to building regulation requirements than before the work was carried out (e.g. cavity barrier).
The government has issued a series of guidance notes on remediating buildings with dangerous cladding materials.
How do the Building (Amendment) Regulations 2018 affect buildings being redeveloped to include a flat/care home/hospital or undergoing another material change of use?
Existing buildings with a storey 18 metres or more in height which are converted to include a dwelling, institution or a room for residential purposes (excluding any room in a hostel, hotel or boarding house) would be undergoing a material change of use defined in regulation 5(k).
The building work would therefore be subject to the requirements in regulation 6(3), which requires that the external walls and specified attachments must only contain materials which achieve European class A2-s1, d0 or class A1. This means that materials which do not achieve that minimum standard will have to be removed or replaced as part of the building work.
An existing building which already contains a dwelling, institution or a room for residential purposes (excluding any room in a hostel, hotel or boarding house) and which is undergoing a material change of use other than that described in regulation 5(k) (e.g. providing a greater or lesser number of dwellings than it did previously) must comply with the requirements of regulation 6(1) and regulation 6(2). The building works would also need to comply with regulation 7.
Does the ban apply to conditions where insulation might be fully encapsulated, such as within masonry wall cavities or precast concrete cladding?
Yes. Regulation 7(2) applies to all external walls (as defined in regulation 2(6)) of relevant buildings (as defined in regulation 7(4)). This includes constructions where the provisions in diagram 34 in section 9 of Approved Document B volume 2 related to masonry wall cavities applies
Where a component is exempted by regulation 7(3) can I use any material, regardless of its combustibility?
No. As explained in paragraph 12.14 of Approved Document B volume 2, regulation 7(2) applies in addition to requirement B4 of Schedule 1 to the Building Regulations 2010. Building work must satisfy all the relevant requirements of the Building Regulations. Approved Document B provides practical guidance on how to meet requirement B4, including guidance in section 12 on the minimum classification of certain exempt items.
Paragraph 12.14 Approved Document B volume 2 provides that consideration should given to the choice of materials used for components exempted in regulation 7(3) as well as their number, size, orientation and position. For example, in relevant buildings as defined in regulation 7(4) membranes are exempted from the requirements of regulation 7(2) but Approved Document B volume 2 paragraph 12.14 a. provides further guidance on membranes and provides that they should achieve at least Class B- s3, d0.
Paragraph 12.6 note 1 of Approved Document B volume 2 provides some guidance with regards to any other parts of an external wall or attachments to the wall which could impact on the risk of fire spread over the wall. Designers should satisfy themselves that other attachments do not adversely impact on the risk of fire spread over the wall in consultation with the building control body.
Are built in LED screens/signage/awnings/advertising screens covered?
If they form part of the external wall these components are covered by the requirements of regulation 7(2). Otherwise, screens/signage/awnings/advertising attached to the external wall are not a specified attachment as defined in regulation 2.
As with question 3, requirement B4 of Schedule 1 to the Building Regulations 2010 must be considered. Designers should satisfy themselves that other attachments do not adversely impact on the risk of fire spread over the wall in consultation with the building control body.
Can I use products which are classified A2-s1, d0 or A1 by delegated acts or European Commission decisions?
Yes. The new regulations state that external walls and specified attachments must be constructed of materials achieving Class A2-s1, d0 or A1, when classified in accordance with BS EN 13501-1:2007+A1:2009. Products which have been deemed by European Commission decisions to meet Class A2-s1, d0 or A1 can be considered to meet the new requirements.
Will products classed as ‘materials of limited combustibility’ comply with the ban?
No. The ban requires materials to achieve class A1 or class A2-s1, d0 only. This is a stricter requirement than the definition of ‘limited combustibility’ in in table A7 of Approved Document B volume 2. Note that this classification is still applicable to the insulation and filler materials (not including gaskets, sealants and similar) etc of buildings above 18 metres in height that are outside the scope of the ban.
What materials are included within the meaning of ‘internal finishes’?
The definition of ‘external wall’ in regulation 2 excludes any decoration or other finish applied to any internal surface forming part of the wall.
Internal finishes (which therefore are not part of the external wall) in this context includes, but is not limited to the following:
- internal skirtings,
- internal architraves
- internal window boards
- internal door thresholds
- internal wall paper, etc.
Internal plasterboard and sheathing boards are not considered as internal finishes and are therefore included in the definition of an ‘external wall’.
Please note that requirement B2 of Schedule 1 to the Building Regulations 2010 still applies to the internal finish (see Approved Document B for further information).
How does the ban apply to curtain walls?
Window frames are exempted from the requirements of regulation 7(2) under the provision of regulation 7(3). Conventional curtain walls consisting of mullions, transoms and glazing can be considered as a window frame. Regulation 7(3) exempt window frames from the requirements of regulation 7(2) this exemption includes all component parts of a windows frame.
However, please note that panels such as spandrel panels and/or other opaque insulated panels in curtain walls are not exempted in regulation 7(3) and therefore must comply with regulation 7(2).
In addition to the above please note that compliance with Requirements B4 of Schedule 1 Part B of the Building Regulations must always be demonstrated.
Is there defined difference between ‘materials’ and ‘components’?
No. Approved Document 7 defines materials as follows:
Materials include manufactured products such as components, fittings, items of equipment and systems; naturally occurring materials such as stone, timber and thatch; and backfilling for excavations in connection with building work.
Are the requirements of the ban of combustible materials in the external wall of buildings applicable to the installation and replacement of gas boilers and flues?
The ban applies to any building work (as defined in regulation 3) carried out in or on ‘relevant building’ as defined in regulation 7(4).
Boiler and flue installations and replacements are likely to constitute ‘building work’ within the regulation 3 definition. The requirement is that building work on buildings in the scope of the ban must be carried out so that only materials which achieve European Classification A1 or A2-s1, d0 become part of an external wall or specified attachment (as defined in regulation 2(6)) unless covered by one of the exemptions in regulation 7(3).
How does the ban affect the installation and replacement of boilers and flues in buildings in scope?
The ban on the use of combustible materials applies to any materials becoming part of the external wall or specified attachments of buildings in scope, other than the components exempted in Regulation 7(3).
References to the ‘external wall’ include anything located within any space forming part of the wall and any decoration or other finish applied to any external surface forming part of the wall (see Regulation 2(6)(a)(i) and (ii)).
For example, the concentric sections of a balanced flue pipe installed in the space forming part of the external wall are likely to be required to meet the requirements of the ban.
The exemptions (see Regulation 7(3)) include membranes, seals, gaskets, fixings, sealants and backer rods. External flue weatherproofing collars are likely to be classified as a seal and therefore exempted as per Regulation 7(3).
If a flue outlet or terminal assembly forms part of the external wall then it will be required to meet the requirements of the ban. If it does not form part of the external wall then it is not required to meet the requirements of the ban as it is not a specified attachment. The same applies to plume management kits. Notwithstanding the above please note that compliance with Requirement B4 of Schedule 1 to the Regulations regarding fire spread over the external wall of a building must always be demonstrated. Consideration therefore should be given to the choice of materials (including their extent and arrangement) used for the external wall, or attachments to the wall, to reduce the risk of fire spread over the wall.
How does the ban affect materials that are temporarily removed to remediate another part of the wall?
Some building work may involve temporarily removing materials which are already part of the external wall in order to replace another part of the wall system, such as where a rainscreen is removed to access the insulation beneath.
Regulation 7(2) states that “building work shall be carried out so that materials which become part of an external wall, or specified attachment, of a relevant building are of European Classification A2-s1,d0 or A1”. It is for building control bodies to assess compliance with this requirement. Materials which are retained and are not impacted by remediation activity are unlikely to be considered to become part of the external wall. However, the application of the ban will depend on the particular circumstances and the specifics of each project should be discussed with the relevant building control body.
It should be noted that regardless of whether the ban applies, compliance with Regulation 4 must always be demonstrated.