Composite Decking Roof Terrace

Is Composite Decking Fire Rated?

Is composite decking fire-rated?

We all know composite decking is a brilliant wood composite solution to timber, but is it 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, are 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.

So what can we take away?

Is Composite Decking fire-rated? Well, all building materials are fire rated in some way, but what we want to know is, what classification is composite decking. For that, we can say that it depends on the individual product but most will achieve a class C and some may achieve a class B fire rating. This does make them safer than using timber, but it means they are not suitable to be used on all buildings where they form part of the external facade.

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