Is Composite Decking Fire Rated?

What is Fire Rating? 

First, let's understand fire rating. Fire rating isn't the term we, as part of the UK construction industry, aren using much. Instead, we are looking at the fire classifications as this is much more descriptive and helpful. You can see from our previous article on the fire classification system that all materials can be categorised from non-combustible with no addition to the spread of fire, to flammable.

So, are wood composite deck boards fire rated? 

The fire rating is more of a classification of its reaction to fire. And, by that, you could argue that composite decking has a fire rating. However, this would be misleading to the majority of people who were asking. 

This classification is different for each board and is dependent on its makeup. Before installing, always make sure that you check the datasheet of the deck board to ensure you know the classification and how it performs. Realistically, composite decking as a wood composite will generally achieve a class C fire classification, but in some circumstances, it can achieve a class B fire rating. 

What does that mean for buildings in the UK?

It means that in the UK, because of recent amendments to the Approved Document B, composite boards should not be installed on residential buildings higher than 11m where they form part of the external facade, e.g. balconies. This means that if you had a balcony on such a building, it must be made using non-combustible materials. 

If the system the composite decking boards are placed on is BRoofT4 compliant, this means composite decking could be used as part of a roof terrace on buildings taller than 11m.