Approved Document B changes balcony guidance

Approved Document B (ADB) was amended in June 2022, with the new guidelines laid out set to take effect from the 1^st of December 2022 on projects in England. For those projects whose initial notice was given to a local authority prior to the 1^st of December 2022 and either the building work has started or building work is starting within six months of the 1^st of December, the prior guidelines still apply.

Fundamentally, the major amendments follow the assent of the Building Safety Act on the 28^th of April 2022. Two of those amendments include a change of guidance applying above 11m (formally 18m) and a broader scope covering more building categories not previously under the requirements of Part B.

Whilst the primary focus of the document is set out as improving and limiting external fire spread, secure information boxes, evacuation alert systems and clarifications/corrections for balconies it is still a significant update. Putting this simply – Part B initially referenced balconies 22 times in the 180 pages of guidance. This amendment references it an additional 16 times.

What are the Regulation B amendments?

Thanks to the new amendments, ADB now features a section dedicated to balconies. The 10.10 guidance specifically applies the following requirements:

In buildings that include a ‘residential’ purpose (purpose groups 1 and 2) with a storey 11m or more in height (see Diagram D6) balconies should meet either of the following conditions.

1. Only contain materials achieving class A1 or A2-s1, d0, except for any of the following.
   1. Cavity trays when used between two leaves of masonry.
   2. Intumescent and fire-stopping materials where the inclusion of the materials is necessary to meet the requirements of Part B of Schedule 1 to the Building Regulations 2010.

• Membranes.

1. Seals, gaskets, fixings, sealants and backer rods.
2. Thermal break materials where the inclusion of the materials is necessary to meet the thermal bridging requirements of Part L of Schedule 1 to the Building Regulations 2010.
3. Any material achieving class A1fl or A2fl-s1 when it forms the top horizontal floor layer of a balcony and is provided with an imperforate substrate under it which extends to the full size of the class A1fl or A2fl-s1 material.

• Electrical installations.
• Fibre optic cables.

1. Achieve both of the following conditions.

1. Have an imperforate soffit which extends to the full area of the balcony, achieves a minimum REI 30 rating, and is constructed of materials achieving class A2-s1, d0 or better.
2. Materials achieving class B-s1, d0 or worse extending beyond the boundary of a single compartment should include a band of material rated class A2-s1, d0 or better, a minimum of 300mm in width centred on that boundary line.

Clause 10.15 (previously, now clause 10.21) includes an additional point to the list:

Any material achieving class A1fl or A2fl-s1 in accordance with BS EN 13501-1 is exempted when it meets both of the following conditions.

1. It forms the top horizontal floor layer of a balcony.
2. It is provided with an imperforate substrate under it which extends to the full size of the class A1fl or A2fl-s1 material.

How do the Regulation B amendments affect balconies?

Firstly, there are now two options in 10.10 for achieving compliance:

10.10 (a) – Other than for height, this is not new guidance for balconies, following the ‘cladding ban’ and exemption list originally published in 2018.

10.10 (b) – This is a new section which gives a second option of compliance when using combustible products.

The wording is specific but confusing. We have reached out to several thought leaders in the industry to get their opinions and clarification. Whilst we might not be able to fully unravel the implications of the new amendments, there seem to be two interpretations from most at present.

Either it can be read as a route to using laminate glass (EVA and PVB’s are both class B) if using Class A strips of 300mm centred on the balustrade line, or it may imply that where a balcony spans between two apartments, a class B material may be allowable as long as it contains a 300mm strip on the line where the vertical barriers would be located on a façade.

However, neither of these assumptions may be correct and with both, there is still doubt about whether the boundary means the façade, the balcony balustrade or something else entirely. There is doubt about how the centred 300mm strip is in relation to the boundary. There is doubt around the examples of class B products expected to be used in balconies – is laminate glass anticipated to be included here or will an entirely different product be used?

To seek clarity, Sapphire continues to work with the ICM to try and seek clarity from the Department for Levelling Up and Local Communities (DfLULC) and the National Fire Chief Council (NFCC). Both parties have been present in the creation of these amendments.

Update, April 2023: At the time of initial publication, Sapphire were seeking clarity from both the Department for Levelling Up and Local Communities (DfLULC) and the National Fire Chief Council (NFCC). Since publication, the DfLULC has responded to us to provide clarity on the 300mm non-combustible strip referred to in point 10.10bii. Summarily, this is referring to balconies which span between two different apartments and the intention is to inhibit horizontal fire spread between the two parts of the balcony. In other words, seeking to avoid a fire spreading from one apartment to another by skipping the compartmentation. 

The changes to Part B have meant a restriction of the materials used to construct balconies and balcony balustrades with consideration for fire safety in mind. Prior to the tragedy at Grenfell Tower, balconies were referenced directly when used as a means of escape from fire and as a means of resisting fire spread, but these additional 16 references show the shift in the perception of balconies as a critical component of fire safety.