Product Review – Composite Decking Products

Product Review – Composite Decking Products

With the introduction of mandatory Bushfire Attack Level (BAL) reporting for properties deemed to be located in bushfire prone areas; it is worth comparing the choices available to achieve a BAL 40 rating for decking – after all, every West Australian needs a place for the barbie.

There are currently only five real choices when it comes to composite decking in the Western Australian construction market;

The major challenge for builders and designers is how this product performs in the Australian weather conditions in comparison to the traditional Australian hardwood timber deck.  Typically manufacturers recommend 5-10mm expansion gaps and a grid pattern/format due to the excessive expansion of the product compared to timber.  The obvious advantage of all composite board products is the lack of required cleaning/oiling/staining maintenance and all the boxes the products tick for sustainable design.  For the sakeof brevity, I will avoid the greater discussion of the building’s sub-structure to achieve a BAL 40 rating.  There is a great deal of complexity when comparing these decking products so for the purposes of this blog, I just wanted to cover the differences under the broad categories;

  • BAL rating
  • Cost
  • Colour
  • Fixings and format size

James Hardie have also anticipated this legislative shift to mandatory Bushfire Attack Level (BAL) reporting for properties and realised the Hardie Deck product to the market.  Although Hardie Deck achieves a BAL 40 rating, it is a compressed fibre cement decking system with greater embodied energy to manufacture than composite boards, so does not fall into the scope of this blog.


The Ekologix boards have two format sizes of 23x88mmx5.4M (RRP $38/length) and 23x137mmx5.4M ($70/length) and is available in four colours.  The manufacturer Ekologix has used HDPE plastic throughout the entire board’s depth means that the board maintains are more natural appearance (in line with natural timber) and can be sanded if required.  The elimination of the cap-stock or veneer coating means that the board performs better from a sustainability design perspective but is more susceptible to staining.  Ekodeck’s competitors have eliminated the staining propensity by the use of the cap-stock or top veneer coating  which is often comprised of PVC.  The incorporation of a top veneer reduces a boards capacity to cope with heavy knocks and punctures as the board’s colour and texture isn’t homogenous throughout the board’s depth (this is not the case with ekodeck.).  Although cost competitive, Ekodeck boards offer no BAL rating to project located in bush-fire prone areas.


Millboard is a composite board product sold by M & B Building Products that is a minimum 100% more costly than M & B Sales standard composite board Modwood.  The product does not achieve any BAL rating so the reason for the increased pricing structure would be explained with the shear volume of product as the format sizes are either 32x176mm 3.6M lengths or 32x200mm 3.6M lengths.  As at March 2016, the range has an availability of 9 colours with some ‘weathered’ textures available.  This product can only be fixed with the proprietary stainless steel star head screw.  The cost of the boards (RRP $141-$170 per 3.6m length) and the associated cost of the fixings certainly will almost invariably result in this product only be specified in up-market individual houses.


Modwood is also an M & B Building Products composite board (grooved) which is supplied at a more competitive price than Millboard.  The most important feature of Modwood is that achieves a BAL 40 rating when using the ungrooved profile.  The two format sizes of Modwood are 23x88mmx5.4M and 23x137mmx5.4M with a RRP of $69-$120.  However, when assessing these apparent cost savings, one must remember the labour cost for fixing the boards is increased with the narrower widths.  Modwood is only available in four colour shades but either smooth or brushed finish.  The boards are glue fixed into a galvanised, powder-coated galvanised or stainless steel proprietary fixing system (called ‘Klevaklip’).

Timber Tech

The six ranges of composite boards by Timber Tech offer 19 colours with brushed and smooth finishes internationally, but only the XLM Plank (square edge) range achieves a BAL 29 rating.  The format size is 135x25mm for both the square edge and grooved boards and sectional profile is very similar to the Trex range.  The reduced BAL rating means that this product is unsuitable for specification in bush fire prone areas or BAL 40.

Trex Decking

Trex Decking offer 10 colours to the Western Australian construction market in square edged and grooved composite boards but there are 30 colours available internationally.  The diversity of colours and quality of finish of the boards are major advantages for specifying this for your next project but is unsuitable for bush fire prone areas as it only achieves a BAL 29 rating.  Interestingly, a number of hardwoods (bushfire resisting timber) also achieve a BAL 29 according to Australian Standard 3959-2009 Construction of buildings in bushfire-prone areas.  The grooved boards use the proprietary (‘universal’) fasteners that comprise of black plastic spacer and stainless steel screws that create 6mm gaps (AS 3959-2009 stipulates a 3mm gap is required to avoid ember attack ahead). The product is fully imported and therefore can create price point fluctuations with movements in the Australian dollar but Trex Decking is certainly a leader in this technology with 25 years of manufacturing composite decking products.  The format size is either 25x140mmx4.88M or 25x140mmx6.0M so the boards will be installed at a much faster rate with the wider board and longer lengths (thus saving on labour costs). Available through

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