The 3 Most Common Misunderstandings of Decking

Following the Grenfell disaster in 2017, anyone designing decking or specifying materials for terrace systems in the UK will – or should be – aware of the requirements of the Building (Amendment) Regulations 2018 relating to the use of fire-rated materials on high-rise residential buildings.

This tragic fire which cost 72 lives could have been mitigated if the non-combustible exterior cladding had been replaced with a like product during renovations, but a cost-saving, combustible alternative was used instead.

The new legislation covers not only external cladding, but also materials used for, and on, balconies and roof spaces.

But as architectural design is about form as well as function, designers are keen to find attractive alternatives to timber and composite decking that are compliant, sustainable, durable and cost-effective.

There are, however, three points that frequently confuse architects.

Grenfell Tower in London after burning

1. At what building height do the regulations apply?

The regulations currently specify that all residential buildings of 18 metres or more must use Class A non-combustible materials for cladding, balconies, roof spaces etc.

However, in 2019 a fire broke out at a student accommodation unit in Bolton, UK. As the building was only 17.8 metres high it was exempt from the regulations and combustible materials had been used in its construction. Subsequent investigations suggested these materials contributed to the spread of the fire.

This prompted discussions in 2020 as to whether the regulations should be amended to include all buildings at or above 11 metres high, in line with regulations in Scotland, and so include all buildings of six or more storeys.

At the time of publishing this post, the regulations still stipulate 18 metres. Our personal recommendation is to play safe and use Class A fire-rated materials for your balconies, roof terraces and decking on any building above 11 metres.

2. Are only Class A rated products acceptable?

To achieve a Class A fire rating certificate, products must undergo fire testing. This is important, as the combustibility of some materials may not be immediately apparent.

There are, however, many materials that are naturally non-combustible – concrete, stone, porcelain, and steel are a few examples. None of these gives off toxic fumes, ignites, or promotes the spread of fire.

For this reason, many decking and terrace products are permitted without certification. Examples include our Atria, and Farrino porcelain surfaces, and our steel planters in Corten and powder-coated finishes.

3. Do the regulations just apply to the decking surface?

No, the regulations cover the entire system. This includes the subframe joists, fire-rated pedestals, and any other components such as shims and spacers used to make the deck level or create an even slope for drainage.

Our fire-safe modular terrace system is fully Class A fire-rated, from its extruded aluminium support joists to its height-adjustable pedestals that remove the requirement for levelling packers.

Fire-safe Terrace at Mustard Wharf, Leeds, UK

Want to gain a greater understanding of fire-rated materials?

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