Substructure

The components required for installing a deck depend on the type of surface it will be built on and the type of beam selected. There are two main installation types: on a solid surface or as a floating structure, such as on a rooftop terrace. Below is an overview of the different types of beams and the corresponding components needed for each installation method.

Fire certification

We often get questions about how a deck behaves in a fire, especially for roof terraces and decks close to buildings. Below, we explain what our fire classification means and where it does and doesn’t apply.

Two ways of looking at fire

There are two separate standards for the fire behaviour of a deck. Each one measures something different.

1. Reaction to fire (EN 13501-1)
   How much does the deck itself contribute to a fire? How quickly does the surface ignite and how far does the flame spread? This classification applies to every deck.
2. External fire exposure of roofs (EN 13501-5, BROOF)
   What happens when a roof build-up is exposed to fire from outside, for example burning debris carried by the wind? This classification matters as soon as the deck is installed on a roof or roof terrace.

Our reaction to fire classification

The classification depends on the profile and the colour:

How do you read this? The letter indicates the fire behaviour: Bfl is better than Cfl, and Cfl is better than Dfl. The s-value refers to smoke production: s1 means little smoke.

The classification applies to the complete build-up

The boards were tested and classified in their end-use application, together with the Duofuse system underneath. The classification only applies to this build-up:

• Duofuse aluminium joists DFBA040 or DFBA043
• Duofuse plastic clips DFC005
• a 40 mm air gap beneath the boards
• a substrate of at least class A2fl-s1, a minimum of 6 mm thick and 1350 kg/m³ (for example concrete or fibre cement)
• open joints of up to 6 mm, both lengthwise and widthwise

Are you laying the boards on timber joists, using different clips or placing them directly on insulation or roofing membrane? Then this classification doesn’t automatically apply.

What about the open joints?

The test was carried out with 6 mm open joints, lengthwise and widthwise. The effect of the joints on flame spread is therefore included in the result. In none of the test samples did the flame break through to the substrate.

A deck on a roof?

For roofs, a different classification applies: BROOF(t1). In Belgium, this is the required class. BROOF is not awarded to the board alone, but to the complete roof build-up: decking board, joist, roofing membrane, insulation and supporting structure.

Duofuse does not currently hold a BROOF classification. Planning a roof terrace? Get in touch and we’ll look at your project together.