Ultra Decking

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Composite Decking Board Cores

I’ve been asked several times by clients domestic and commercial, does the composite decking board depth and core type make a difference with strength and overall performance over the decks service life.

On this page we will discuss the different depths and design of all composite decking boards and what truly matters when purchasing.

Square hollow composite decking

Ultra Deckings home choice range of composite decking boards are 150mm wide and 25mm deep.

The square hollow core is a very commonly sold design here in the UK. Most customers first thoughts are, the deeper or thicker the decking board the stronger it will be. This isn’t always true, when choosing a square hollow composite decking board, the key part to confirm and check is the depth of the top and side walls inside the square core. The square core top and walls regardless of the boards overall depth should be at least a minimum of 5mm on each side wall including the top and bottom of the square core. If the walls and tops of the square core fall below 5mm the strength is more than likely very weak leading to structural problems such as cracking, splitting or even failure over time.

With a square hollow core to ensure its structural strength over the decks service life for a home or residential installation, the cores square thickness must be a minimum of 5mm and above. The sub-structure or joists should have a span of no more than 300mm. You could go to a 400mm span between joists, but it isn’t advisable. During accelerated time lapse testing with a 400mm span between joists has led to cracking and splits and eventually structural failure.

In summary, a square hollow core decking board of any thickness for residential/home decking projects must be a minimum of 5mm in depth on the side and top walls to ensure the required strength over the decks service life.

Circle Hollow Composite decking

Ultra Deckings Premier range is designed with a circular hollow core. Our experience has shown this design to be of similar strength and durability to that of a composite decking board with a solid core.

Independent tests from SGS has confirmed that Ultra Deckings Premier Range of composite decking boards can withstand the stresses and weight of up to 4 average family cars before failure. The Premier range of composite decking boards are recommend for areas with public access and high footfall. Of course, residential customers can opt for the added strength and durability of the Premier range for that added peace of mind.

For commercial customers, we strongly recommend a circular hollow core as the smart choice. The Ultra-Decking Premier and Signature ranges are designed and built to withstand high footfall areas offering many years of service. Circular hollow cores can distribute impact or shock waves evenly throughout its core and easily deal with the harshest weather conditions, especially changes to temperature fluctuations that are experienced here in the UK. Many industry experts and commentators suggest and recommend that a circular hollow core composite decking board has improved strength qualities and better equipped to deal with temperature contraction and expansion.

Good visual tips to confirm quality is the circular cores circular diameter. A large diameter is a good indication of the board’s weakness. In addition, view the inside of each circular core, if you can view lines or scratches down the inner core’s length, this is another good indication that the mould used to produce the decking board is of poor quality craftmanship.

In summary, a circular hollow core decking board is the intelligent choice for commercial composite decking usage offering similar strength to that of a solid board and gives it flexibility for expansion and contraction.

Solid composite decking board

Solid Composite decking boards come in 2 options, a full or a half solid board.

Solid composite decking boards are an additional option for commercial decking projects. Subject to quality, they have no match in strength and are built to withstand large footfall or public areas and offer a long lifespan due to the boards dense design.

The only downside to a solid composite decking board is expansion and contraction. The dense design does not easily stand up to fast temperature changes as easily as a hollow design. This can lead to movement causing warping in some instances.