Composite Deck Boards vs Hardwood Balau Decking

I’ve often been asked to quote, on or at least comment on, composite decking. Firstly we need to have a look at what composite deck boards are.

Composite deck boards are generally made from plastic and saw dust which can be anything from saw dust, wood chips to wood fibre pieces or bamboo. They can be either be new or recycled materials. One method of manufacturing composite deck boards is by extrusion. That is the materials are mixed together and forced through an opening to create a relatively consistent size and shape. Compression moulding is the other method used and consists of taking the combined liquid materials and compressing them under high pressure and heat into a mould to create the deck board.

Composite boards cannot be used as structural material as they do not have the required structural properties of, for instance, S5 SABS approved structural or industrial grade treated pine, or balau for that matter. As such the substructure of a deck still needs to be built using H3 CCA Treated pine. If the argument is that composite decks will last longer than solid timber, then half that argument is invalid because the structure is not made from composite materials. It is only the deck boards that are from composite materials and cannot “rot” in the traditional sense. However composites can fail if the process they underwent was not sound. There are various failures that can occur. A search on Google for “composite fails” will return many ways these boards can fail from a sub standard manufacturing process to fading in extreme direct sunlight, to warping, cupping or twisting due to heat from the harsh African sun.

Sustainability and “eco friendly” is often used as an argument in favour of composites. The balau and pine we use in decks is from sustainable forestry and is certified as such when imported or harvested locally. Producing composites also requires a lot of heat which is obtained from which source? So although composites can be made from recycled materials, one also needs to factor in the carbon foot print of making them, even though it is probably less than the carbon foot print of harvesting solid timber. Composites therefore do not carry a zero carbon foot print.

From a cost point of view composites are generally more expensive than balau. As with anything, you can get cheap or expensive and the risks of buying cheap composites speaks for itself. Some composites can be up to 4 times the price per square metre of balau. A cheap composite will tend to fail quicker as opposed to a more expensive one. If the cost of these boards is up to 4 times the price of balau then it stands to reason that  ALL the balau can be replaced up to 4 times before the cost becomes the same. It is highly unlikely that you will need to replace your deck surface four times in the life of the deck. What will commonly occur in a balau deck surface is that some boards will fail before others. Any failure of balau deck boards is normally long-term in any event. Deck boards are relatively easy to replace and relatively inexpensive. It is the structure that is expensive to replace and normally results in the whole deck having to be replaced. If our structures are both CCA treated pine in both types of deck, then the greater risk lies in the structure, not the boards.

The fixing system generally used to fix these boards to the pine substructure is a hidden screw of sorts and again there are various products available each one with it’s own advantages and disadvantages. A plastic clip is often used which is slotted into a groove routed along the edge of the board and then fixed to the bearer. Two boards often share a single clip which is then concealed below the deck board. So no screw holes through the face of the board. With the screw head being so small they can fail in that the screw can be screwed too far through the plastic clip. The clip itself is plastic and at certain temperatures will fail. The clip can only be guaranteed against failure below certain temperatures. In my opinion nothing replaces a Kalgard coated decking screw counter sunk through the face of a solid timber board to limit failure. In a balau deck, screw holes are filled with a clear epoxy and saw dust mixture so are not as visible as one would think once filled and sanded flat.

Scratches and fading in composites should be taken into account. A lot of manufacturers of composites guarantee a maximum percentage fade rate. How does one measure 10% fade? If a composite deck fades or gets scratched it can’t be sanded to remove these.

Maintenance of the deck is often used as an argument for using composites over balau. Water is largely drawn into wood through the end grain and not the face or side grain. Being balau it is naturally resistant to water ingression. If you take a 20 year old piece of good quality yellow balau and cross-cut it, you will most often find that no water has been absorbed through the board. Balau deck boards can be left un-oiled which will result in a grey appearance. Oiling or not oiling a deck won’t increase or decrease the life span of the deck by any material length of time. If oiled, maintenance is simple. Oil can be sprayed, brushed, wiped, sponged or even dipped. And oil won’t peel and flake. Coatings will. So it is quick and easy to maintain. If left un-oiled a pressure clean every 6 to 12 months is sufficient to keep your deck looking good.

Based on the above I am more concerned about the structure of a deck than the surface one uses. Structures are costly to replace. Deck boards are not. The above arguments for composites do not, in my opinion, warrant using them as opposed to balau.

We will however install a composite deck for you if you so wish, but I am not convinced that you will achieve the desired result by switching from solid timber to composites.

For a quote on your deck and other timber related structure please contact us using the contact us form below or call us on 082 496 5444.

Wooden Decks and Balau Deck Boards for Sale Durban

Besides offering a full wooden deck building service in Durban of supply and install, we also sell balau deck boards to end users for use in wooden decks in Durban and KZN.  Please use the contact us form below to enquire about deck building services or read on for more info on sale of deck boards and decking materials.

Because we secure our balau deck boards in bulk we are able to offer these deck boards to the wooden deck builder or end-user at a highly competitive price and more competitively than your popular outlets in Durban.

We stock largely 19mm x 68mm and 19mm x 90mm wooden balau deck boards but other sizes and species are also available, on request. We stock a range of lengths from 2.4m to 4.8m. Please check with us what we have in stock before ordering and provide us with the rough dimensions of your wooden deck so we can select the correct lengths for you to minimize waste. If for instance you are building a wooden deck measuring 4.8m then you would opt for 2.4m deck boards and space your joists with centres of 400mm or 480mm (but not 450mm or 500mm) as these are all factors of 2.4m. On the other hand if your wooden deck measured 5.4m long then you would opt for 2.7m deck boards and space your joists with centres of 450mm or 540mm being a factor of 2.7m. This way the off cut at the end of each deck board is minimized and a saving can be obtained. I will gladly help you plan your substructure and deck boards so as to build a structurally sound deck and minimize waste. Contact me below with the size of your deck and the height above ground.

There are mainly two different types of balau that can be purchased, red and yellow balau. In my experience the yellow balau is harder and therefore more durable. The red balau I have bought in the past seems to be more porous and will therefore absorb more water and rot more quickly. Although balau is very hard, contains natural oils and resins and repels water naturally all wood will eventually rot. The aim is to choose a decking timber that will outlast other timbers but is still affordable and easy on your pocket. We stock only yellow balau.

We sell mainly reeded deck boards. These are the deck boards with grooves on one side. The grooves are not there for anti-slip as is commonly thought. They are in fact there to be placed down against the joist. The reason is to allow any trapped water to dissipate quickly. By keeping the water away from the gap between the deck board and the joist will reduce rot to a degree and result in your wooden deck lasting longer.  It is not absolutely essential but does help to some degree.  Also by having the grooves up you cannot epoxy the screw holes closed, because you can’t sand it off due to the grooves, thus allowing more water to pool in the counter sunk screw hole causing accelerated rot. Grooves up also traps dirt and grime which actually causes the deck surface to become more slippery than a smooth surface. So always grooves down.

We are able to deliver in the greater Durban area. Please enquire about delivery charge.

To contact us for a full wooden deck building service in Durban, or to order deck boards and other timber decking materials, you can call us on 082 496 5444 or use the contact us form below.