Assessments of external wall cladding systems

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Heads of Local Authority Building Control

Approved Inspectors

10September 2018

Dear Sir or Madam,

ASSESSMENTS OF EXTERNAL WALL CLADDING SYSTEMS

The purpose of this Circular Letter is to draw attention to issues about assessments of external wall cladding systems.

Scope of this Circular Letter

The guidance in this Circular Letter applies to buildings and building work in England.

This guidance is principally relevant to projects for which a full plans application is made or initial notice submitted from the date of this letter. However, for existing projects, building control bodies may wish to reconfirm that satisfactory evidence has been submitted that the requirements of paragraph B4 of Schedule 1 are being met.

Introduction

The Government has recently consulted on amendments to the guidance in Approved Document B to restrict the use of assessments in lieu of tests. This reflects concerns reported in Dame Judith Hackitt’s report into Building Regulations and Fire Safety, and raised by many others, that assessments have been used inappropriately to support proposals for cladding systems. The Government shares those concerns and proposed in the consultation changes to guidance to deal with this. The Government has also commissioned the British Standards Institution to draft a new standard for the extended application of BS8414 results.

The Government has also consulted on proposals to ban the use of combustible materials in external wall systems for high rise residential buildings.

Pending Government decision on the outcomes of those consultations, this letter provides guidance to building control bodies on how they should be assessing

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compliance with the requirements of Paragraph B4 of Schedule 1 to the Building Regulations 2010 as amended.

Current Guidance

Section 12 of Volume 2 of Approved Document B (Fire safety – buildings other than dwelling houses) sets out two ways for duty holders to demonstrate compliance with the requirements of Paragraph B4 of Schedule 1 (External Fire Spread) to the Building Regulations 2010 as amended, in relation to buildings with a storey 18m or more above ground level.

These are:

• For any insulation product, filler materials (not including gaskets, sealants and similar) etc used in the external wall construction to be of limited combustibility (as defined in Table A 7 of Appendix A of Volume 2 of Approved Document B); or

• For the external wall to meet the performance criteria given in the BRE report Fire performance of external thermal insulation for walls of multi storey buildings (BR 135) for cladding systems using full scale test data from BS 8414 -1: 2002 or BS 8414-2: 2005.

The Government takes the view that, pending decisions following the consultations, and the publication of any new standard, building control bodies should only accept evidence of either of these two ways to demonstrate compliance. Building control bodies should look for clear evidence of the classification of materials used, to meet the definitions in Table A7 of Appendix A; or clear evidence of the results of tests carried out in accordance with BS 8414. Test results must be relevant and appropriate for the proposed external wall construction. Building control bodies should not accept proposals which lack such evidence.

Enquiries

Any enquiries on this Circular Letter should be addressed to enquiries.br@communities.gsi.gov.uk.

Yours faithfully

Bob Ledsome

Deputy Director

Technical Policy Division

Building Safety Portfolio