Three months after the Grenfell Tower tragedy, we are starting to gain a better understanding of the issues raised by the fire. While it will be some time before we fully understand how it started or why it took hold in the way it did, a clearer picture is starting to emerge of how the Building Regulations ought to be interpreted, what panel types are most at risk and what steps parties can take in response to combustible cladding related issues. Some of the latest developments, plus an update on liability issues, are considered here.
Updated Building Regulations guidance
The Building Regulations require that in buildings over six storeys, any insulation product or filler material used in external wall construction should be of “limited combustibility” or Class A2.1. There has been some debate about the extent of this requirement because the Building Regulations also suggest a lower safety score of Class 0 (Euroclass B) for all external surfaces for tall buildings. It has now been clarified that while the surface of a panel may be classified as Class 0, the limited combustibility requirement for filler materials means either BS476-4 or 11, or EN 13501-1. Alternatively, external wall surfaces may be tested to BR135.
Conclusions from the panel safety tests and further guidance
Safety tests have been taking place to identify whether Aluminium Composite Material (ACM) panel samples, the type used at Grenfell Tower, satisfy the Building Regulations limited combustibility requirements. The tests have now concluded that ACM with unmodified polyethylene filler with any type of insulation presents a significant hazard on buildings over six storeys. Whilst ACM panels with a fire retardant filler could be used safely with non-combustible insulation such as stone wool, this depends on the insulation used and how it is fitted. ACM with a limited combustibility filler can be used safely subject to how it is fitted.
Following the fire there has been concern about non-ACM panel types with a near identical construction to those used on Grenfell Tower. While guidance on non-ACM panel types is still awaited, a list of historical data on cladding systems which have passed the BS8414 test in the Building Regulations has now been published to assist in identifying similar cladding systems.
Assessing liability for those involved with at-risk projects
If remedial works are required, it is recommended that professional advice is taken to ensure any works are carried out safely and that any recladding works satisfy the necessary standards. It has now been confirmed that new cladding must satisfy Class A2 to BS EN 13501-1 standards.
The liability of those who may have specified, installed or certified combustible cladding will depend on the relevant circumstances. Parties can take three steps to start assessing the extent of any liability.
Firstly, it is important to establish the relevant facts with the assistance of those involved as to how and why combustible cladding came to be installed. The cladding specification should be reviewed to establish what was originally planned.
Secondly, parties should consider whether final certificates under the construction contract were issued. Final certificates can act as a conclusive evidential bar to claims where the relevant timescales for challenge have expired and the certificate covers the relevant works. Partial certificates were considered in a recent judgment concerning liability for defective cladding. The court held that as the certificate had been issued for one phase of the works, it was only conclusive for the part of the works which it covered.
Thirdly, as many buildings requiring remedial works would have been constructed years ago, consideration of limitation periods will be relevant. The expiry of a limitation period will act as a defence to subsequent claims. The standard contractual limitation periods are six years for contracts signed under hand and 12 years for those executed as deeds. Complex arguments arise in respect of economic loss, where losses may not arise until years after completion. The limitation period for negligence is three years from the first knowledge of the cause of action subject to an overriding 15 year long-stop. The parties may displace the standard limitation periods by bespoke terms. In Inframatrix v Dean Construction, a case concerning roofing and cladding works to a new factory, the parties agreed a one year limitation period following which any claims were time barred. In another defective cladding case, the court made clear that contractual limitation periods will not bind third party claims, such as where contribution proceedings are issued.
The Grenfell Tower fire has initiated the largest health and safety review in the UK since 1945. This includes a public inquiry and independent review of Building Regulations and fire safety. Events following the Grenfell Tower fire have been extremely fast moving but a clearer picture is now starting to emerge of how the information and guidance issued can be applied to assess health and safety risks, and where to start when assessing liability issues.
About the author: Barry Hembling is a partner in the construction and engineering team at Fladgate LLP
 Paragraph 12.7 of Approved Document B
 See for example Table A
 Matthew Hall Ortech Limited v Tarmac Roadstone Limited  EWHC Technology 352 in relation to the Institution of Chemical Engineers Model Form of Condition of Contract (the "Red Book") and Crown Estates Commissioners v John Mowlem & Co Ltd  70 B.L.R. 1, CA in relation to the JCT Standard Building Contract 1980
 Amec Foster Wheeler Group Ltd (Formerly Amec Group Ltd) v (1) Morgan Sindall Professional Services Ltd (2) Morgan Sindall Group Plc  EWHC 902 (TCC)
 Co-Operative Group Ltd (Claimant) v Birse Developments Ltd (In Liquidation) (Defendant) & (1) Stuarts Industrial Flooring Ltd (In Administration) (2) Jubb & Partners (A Firm) (3) Geofirma Soils Engineering Ltd (Third Parties)  EWHC 530 (TCC)
 Inframatrix Investments Ltd v Dean Construction Ltd  EWCA Civ 64
 Bloomberg LP (Claimant) v (1) Sandberg (A Firm) (2) Sandberg LLP (3) Buro Happold Ltd (Defendants) Malling Pre-Cast Ltd (Third Party)  EWHC 2858 (TCC)