Welsh Government bans the use of combustible materials in buildings over 18m

27 January 2020

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The Welsh Government has published amendments to Building Regulations in Wales restricting the use of combustible materials in the external walls of certain buildings over 18m in height bringing it into line with the earlier and comparable ban in England.

The restrictions apply to the external walls and specified attachments for residential blocks of flats, student accommodations, care homes, sheltered housing, hospitals and dormitories in boarding schools with a storey above 18 m in height.

The amendments require that all materials which become part of an external wall or specified attachment achieve European Class A2-s1, d0 or Class A1.

The amendments came into force on 13 January 2020 with very short and limited transitional provisions.

The Transitional Provisions

The amendments made do not apply in any case where a building notice or an initial notice has been given to, or full plans deposited with, a local authority before the day these Regulations come into force and either the building work to which it relates—

(a) has started before that day; or

(b) is started within 8 weeks of the amendments coming into force (this would be 9 March 2020).


The external wall of a building includes a reference to:

i. anything located within any space forming part of the wall;

ii. any decoration or other finish applied to any external (but not internal) surface forming part of the wall;

iii. any windows and doors in the wall; and

iv. 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, but not access only for the purpose of carrying out repairs or maintenance;

Specified attachment means:

i. a balcony attached to an external wall; or

ii. a solar panel attached to an external wall.

Components exempted from this requirement include:

a) cavity trays when used between two leaves of masonry;

b) any part of a roof (other than any part of a roof which falls within paragraph (iv) of regulation 2(6)) if that part is connected to an external wall;

c) door frames and doors;

d) electrical installations;

e) insulation and water proofing materials used below ground level;

f) intumescent and fire stopping materials where the inclusion of the materials is necessary to meet the requirements of Part B of Schedule 1;

g) membranes;

h) seals, gaskets, fixings, sealants and backer rods;

i) thermal break materials where the inclusion of the materials is necessary to meet the thermal bridging requirements of Part L of Schedule 1; or

j) window frames and glass.

Material change of use:

  • Where the use of a building is changed such that the building becomes a residential block of flats, student accommodation, care home, sheltered housing, hospitals or dormitories in boarding schools with a storey above 18 m in height the construction of the external wall, and specified attachments, such work, if any, must be carried out as is necessary to ensure that any external wall, or specified attachment, of the building only contains materials of a minimum European Classification A2-s1, d0 or A1.

Relevant statutory instruments, amendment regulations and Approved Documents:

For more information on the amendments and how these may affect your project please speak to your NHBC Surveyor or Project Manager.

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