The ban on combustible materials in the external wall of buildings - what you need to know

12 minute read
07 December 2018



This insight was published prior to the Building Safety Act receiving Royal Assent on 28 April 2022. As such, whilst accurate at the time of publication, its contents may have been superseded by the changes implemented by the Act or its related secondary legislation.

You can find a list of all Gowling WLG articles relating to the Building Safety Act here.

Government introduces ban on combustible materials

Since the publishing of the Hackitt Interim Report in December 2017 and the Final Report in May 2018, the Government has been under increasing pressure to revise building regulations permitting the use of combustible materials in cladding systems.

On 29 November 2018 the Government made 12 announcements in relation to fire safety in high rise buildings over 18m high[1]. The most important of the announcements was the publishing of the Building (Amendment) Regulations 2018 (S.I. 2018/1230) (the "Amendment Regulations") which - when they come into force on 21 December 2018 - will introduce significant changes to the Building Regulations 2010, the most notable being the total ban of combustible materials in the external wall of buildings subject to some key exemptions. Updates to the familiar Approved Documents B and 7 have been published to take account of the Amendment Regulations. We explain the key changes below.

In accordance with section 14(3) of the Building Act 1984, these Amendment Regulations were made after consultation with the Building Regulations Advisory Committee for England and with other bodies representative of the interests concerned (including, for example, the recommendations of the Hackitt Report).

Ban of combustible materials in the external wall of buildings

Regulation 7 of the Building Regulations 2010 requires that materials used in building work are appropriate for the circumstances in which they are used. New regulation 7(2) of the Amendment Regulations - being the most significant of the changes introduced - requires that all materials which become part of (what have now been defined within the Amendment Regulations as) an 'external wall' or 'specified attachment' achieve European Class A2-s1, d0 or Class A1. This means is that only limited combustibility (A2-s1, d0) or non-combustible (A1) materials will be permitted.

Certain limited components are exempted by regulation 7(3). This move towards a more prescriptive standard is a departure from the level of discretion that the previous building regulations regime permitted, albeit that it does not go as far as some industry groups wanted, and is a move towards eliminating the use of combustible materials in cladding systems.

Amended regulation 7(2) will apply to any building with a storey at least 18m above ground level and which contains one or more dwellings; an institution; or a room for residential purposes. This would include student accommodation, care homes, sheltered housing, hospitals and dormitories in boarding schools but would exclude any room in a hostel, hotel or a boarding house, and all commercial buildings.


The definitions of what constitutes an 'external wall' and 'specified attachments' are now included in regulation 2 of the Amendment Regulations. An external wall will include:

  1. anything located within any space forming part of the wall;
  2. any decoration or other finish applied to any external (but not internal) surface forming part of the wall;
  3. any windows and doors in the wall; and
  4. any part of a roof pitched at an angle of more than 70 degrees to the horizontal if that part of the roof adjoins a space within the building to which persons have access. However, access only for the purpose of carrying out repairs or maintenance is not included.

This therefore includes any boarding, insulation, cavity barrier and such like within the make-up of the external wall.

The regulations also apply to "specified attachments", which will include:

  1. a balcony attached to an external wall;
  2. a device for reducing heat gain within a building by deflecting sunlight which is attached to an external wall; or
  3. a solar panel attached to an external wall.

Approved Document B: Fire safety

Approved Document B has been updated to provide guidance with regards to the requirements of regulation 7(2) set out above. In particular, paragraph 12.6 of the amendments states that "…any insulation product, filler material (not including gaskets, sealants and similar) etc. used in the construction of an external wall should be of limited combustibility or better…". This is then consistent with the requirements at regulation 7(2) for certain materials used to achieve European Class A2-s1, d0 or Class A1. The effect of this is that - with very limited exceptions - it is no longer permissible to encapsulate combustible insulation within masonry or concrete walls.

Additional minor changes have been made to Approved Document B Volume 2 to update some of the references as a consequence of the updated guidance.

Transitional Provisions

Although the Amendment Regulations come into force on 21 December 2018, they will not apply where a building notice or an initial notice has been given to, or full plans deposited with, a local authority before 21 December 2018 and either the building work to which it relates has started[2] before that day, or is started within two months from such date.

The Amendment Regulations will come into effect very soon, and it is advisable for steps to be taken now in relation to schemes that are being currently planned. Government guidance indicates that adequate commencement of works would likely be indicated by work such as:

  1. excavation for strip or trench foundations or for pad footings;
  2. digging out and preparation of ground for raft foundations;
  3. boring for piles or pile driving; or
  4. drainage work specific to the building(s) concerned.

Material Change of Use

Amended regulations 5 and 6 provide that, where the use of a building is changed such that the building becomes a building described in regulation 7(4)(a) (being any building with a storey at least 18m above ground level and which contains one or more dwellings; an institution; or a room for residential purposes), the construction of the external wall, and specified attachments, must be investigated and, where necessary, work must be carried out to ensure they only contain materials achieving European Class A2-s1, d0 or Class A1. The important change here is that a change of use is much more onerous than merely remediating. For remediation, only materials that become part of the wall are subject to regulation 7(2) whereas with a change of use, all materials in the wall will have to comply, whether new or existing. This will have particular implications for timber-framed buildings.

This is likely to be most significant for strip out and conversion works taking place after 21 December 2018.

Approved Document 7

The familiar Approved Document 7 relating to materials and workmanship has been updated to introduce the restriction on the use of combustible materials in external walls. The following text is introduced:

"The Building Regulations restrict the use of combustible materials in the external walls of certain buildings over 18m in height. Refer to regulation 7(2) of the Building Regulations and to Approved Document B: volume 2, part B4 for details."

HHSRS Guidance

On 29 November 2018, the Government issued operating guidance in relation to the Housing Health and Safety Rating System (HHSRS); the risk-based assessment evaluation tool that is used by local authorities to identify and protect against potential risks and hazards in private buildings. The new HHSRS guidance relates specifically to the potential for the hazard of fire in cladding systems on high rise residential buildings.

The HHSRS tool is used by local authorities to discharge their duties under the Housing Act 2004 where category 1 (general duty to take enforcement action) or category 2 (discretionary power to take enforcement action) hazards exist on residential premises or under the Building Act 1984.

The guidance suggests that subject to certain exceptions[3], the presence of ACM (category 2 or 3) cladding, or any other cladding and filler or core that is combustible, would be a deficiency that contributes to the hazard and would require rectification; either by the private landlord of the building or by intervention by the local authority.

The costs of local authorities taking any necessary emergency remedial action can be recovered from the private landlords. We note, however, that it is not the intention for the Amendment Regulations to be retrospectively applied through the Housing Act 2004 or the Building Act 1984. There have been no amendments to either of these pieces of legislation.

So, what does this mean in practice?

For starters, all new buildings which fall within the criteria will have to have their external walls constructed completely of non or limited-combustibility materials and any building which is required to be re-clad as a consequence of currently having ACM cladding or any other non-compliant cladding system will have to be re-clad in materials which are of limited combustibility or non-combustible; and unless the proposed system passes the large-scale BS 8184-1 and 2 tests, this could include any insulation or other boarding etc. which forms part of the external wall structure, also having to be replaced, although further guidance is being sought on this.

Secondly, any building which undergoes a change of use to become a building which falls within the regulation 7(4)(a) categories will also have to comply with the amended building regulations - so the office tower blocks being converted to apartments which have been popular over the last few years will fall within this criteria.

But is this the end of the story?

There are still questions being asked as to whether the scope of the guidance and the height of buildings[4] to which the criteria applies is right and further consultation and lobbying is taking place in this regard, so there may yet be further changes which would help to simplify the position leaving everyone in the industry clear as to the requirements, but in the meantime, further guidance on best practice is expected imminently.

If you have any queries on these changes or other matters, please contact Sue Ryan or Tom George.


[1] i.e. there has been or will be adequate commencement of the works
[2] Many industry groups have been lobbying for the 18m requirement to be reduced to 11m
[3] Government Building Safety Programme - update and consolidated advice for building owners following large scale testing
[4] Many industry groups have been lobbying for the 18m requirement to be reduced to 11m and Scotland has just approved a change from 18m to 11m.

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