On 21st December 2018, the Government in England implemented an amendment to the Building Regulations prohibiting the use of ‘combustible cladding’ in high-rise relevant buildings with any storey over 18 metres.
The regulation adaptations will apply whenever work is carried out in England and comes within the scope of Building Regulations, whether a newbuild or refurbishment project It is also applicable if a building, which is not currently within the scope of the ban, subsequently undergoes a change of use that means it falls within remit, at which point the external walls must be brought into compliance with the new requirements.
The recently built Bermondsey Works in London is a 60m high, concrete frame with lightweight steel frame infill panel, structure containing 148 apartments, a school and three floors for the City of London Academy. As a building over 18m high containing one or more dwellings, it’s a perfect example of where the new Building Regulations in England now come into force regarding combustible cladding in high rise buildings. It also demonstrates how using an Alumasc Facades by K Rend EWI system provides the perfect BBA accredited solution for modern framed construction.
The change is being implemented through explicit regulation rather than guidance, specifically by changing Regulation 7 of the Building Regulations which deals with materials and workmanship, and now states that building work shall be carried out:
a) with adequate and proper materials and
b) in a workmanlike manner
The materials were previously subject to older British Standard classification and this has been changed to the European classification. The regulation now says:
“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, classified in accordance with BS EN 13501-1:2007+A1:2009“
BS EN 13501-1 defines the classes A1 and A2 as follows:
Class A1 - Will not contribute in any stage of the fire, including the fully developed fire
Class A2 - Will not significantly contribute to the fire load and the fire growth in a fully developed fire
The relevant characteristics “s1” and “d0” are defined as follows:
s1 - Weak or no smoke
d0 - No flaming droplets
“Relevant” buildings mean a building with a storey (not including roof-top plant areas or any storey consisting exclusively of plant rooms) at least 18 metres above ground level and which “contains one or more dwellings; contains an institution; or contains a room for residential purposes but does not include a room in a hostel, hotel or boarding house.”
By including institutions (which are defined in the Regulations) it also covers some residential schools, care homes and hospitals, sheltered accommodation, student residences or other institutional accommodation blocks. The final group includes any building which contains “a room for residential purposes”. Hostels, hotels or boarding houses are excluded, unless they are converted into residential accommodation, such as student housing.
The material change-of-use requirement is very important, because it means that – for example – a hotel may be built using materials not permitted in a student residence, but the hotel cannot then be converted to a student residence without replacing any non-compliant materials.
The Exicco Pro system from Alumasc Facades by K Rend is currently a BBA certified system which can meet the new regulations specified. It has been tested to BS EN 13501-1:2007+A1:2009 achieving A2-s1, d0 classification ensuring it is suitable for high-rise construction. It is designed for use on framed construction including steel or timber frame, incorporating a drained cavity.
The design of high rise buildings with cladding will often contain a cavity which is vented and/or drained (rather than ventilated) and it is also necessary to ensure the spread of fire between floors is prevented. The Exicco system is designed to mitigate this risk through the incorporation of noncombustible insulation at the interface in the cavity and also the vertical and horizontal fire compartmentalisation. Detailed in the images below, the fire strip is designed that in the event of a fire, the cavity will close and prevent the spread of flames by starving the fire of oxygen.
Exicco also meets the requirements of key insurers such as NHBC and Premier Guarantee in addition to those of the key accreditation bodies such as the BBA (as mentioned) and the CWCT (Centre for Window & Cladding Technology).
The Exicco system still offers design flexibility through a variety of sub systems within the range which meet the new regulations, insulation requirements and aesthetic styles:
- Silkolitt Exicco pro
- VBriQ Exicco pro
The pro element of the system dictates the use of Mineral Wool insulation Silkolitt and VBriQ offer diverse aesthetic finishes. The Silkolitt element of the system presents a textured render finish with a choice of grain sizes depending on how smooth you require the finish. Although there is a standard colour range Silkolitt is offered in any colour within the NCS range, offering endless options.
VBriQ offers a brick effect in a variety of standard colours or can match most UK brick types.
For more information on the Exicco Systems or the new Regulations, please contact K Systems.