Choice Comparisons – Composite vs Solid Timber

A comprehensive breakdown of the different benefits and attributes of solid timber and Urbanline Composites when used for decking and cladding applications.

Choice Comparisons – Composite vs Solid Timber
Attribute Timber
The most common solid timber species suitable for claddings and decking:
Urbanline Architectural Composite products
Durability The natural durability rating of a timber species rates the timber’s natural resistance to attack by wood-destroying fungi and wood destroying insects. The sapwood of all timber species has poor resistance and so the natural durability rating applies only to the heartwood of a timber species. The natural durability rating is not intended to predict a precise life expectancy for a species, due to the variability within a species and because of the differences in conditions between sites and applications where the timber species might be used. Wood-Plastic Composites are produced for their ability to be durable, without containing toxic chemicals. The physical and mechanical properties of Wood-Plastic Composites depend greatly on the interaction of the plant and polymer fibres, within the material. The Composites supplied by Urbanline Architectural, are produced with highly durable raw and recycled materials, to ensure product longevity. These Composites are termite proof and waterproof, have a longer life span and are attractive in design and durable in structure. More and more, people are opting to use Composite materials for walls, decks and screening applications.Latitudes’ and Millboard’s limited 25 year residential warranty is assurance the manufacturer is prepared to back their products for years of hard wearing and continuous use.
UV Stability Australia is well known to have one of the highest levels of ultra violet exposure in the world. The frequency of sunny days and high temperatures is instrumental in the breaking down of external finishes, causing timber movement and weathering of the exposed faces of timber products.Maintenance/coating of timber is required, not only to maintain the colour or look of a project, but also to protect the timber from harmful UV rays. Coating keeps the cells hydrated and fed, avoiding separation and shrivelling up, which results in cracking and twisting. Composite products has been formulated especially for the high UV exposure in Australia. Our Composite products have been tested extensively, including accelerated weathering testing of up to 30 years. Composite products are manufactured with UV stabilisers. For instance, Latitudes decking is manufactured using several polymers—polyethylene (low-density or high-density), polyvinyl chloride and polypropylene—plus wood flour and additives that stabilise the plastic and protect it from damaging UV rays.
Rot Resistance One of the biggest threats to timber is fungal decay. Both wet rot and dry rot, united in their love of damp, can cause serious structural damage to your timber project and investment. Composites are rot resistant.
Pest Resistance All woods are susceptible to termite attack, unless they are treated with an approved timber treatment/preservative. Composites are not susceptible to termite attack.
Mould Resistant Some timber species are susceptible to algae and fungal attack. Composites are algae and fungal resistant and are manufactured with mould inhibitors.
Shrinkage and Warping Timber expands and contracts in width, in direct proportion to the increase or decrease of moisture content. Timber is a hygroscopic material, which means it releases or absorbs moisture to equalise with the air/medium it is in contact with. The amount of moisture in the air is a relationship between temperature and relative humidity. Therefore, we can say that timber expands and contracts in width, in response to ambient changes in temperature and humidity.Factors that influence movement are tangential shrinkage, annual weather cycle, level of sun exposure, size of area for product to be installed and weather protection during construction. Shrinkage and warping occurs when all these factors are not taken into consideration when the timber is installed and also if the product is not maintained periodically. Expansion and contraction is minimal and predictable when installed to manufacturer’s recommendations and installation instructions.Composite products do not warp and distort when installed correctly – no more hassles or ongoing concerns!
Maintenance All timber decks and cladding need periodic maintenance to keep them looking good and to preserve the cell structure of the timber, which prevents deterioration. Depending on circumstances, you should re-coat your timber at 6-24 month intervals.Timber needs hydration and to maintain a relatively even moisture content. It’s also important to provide protection against fungal attack, which can result in discolouration and/or black spotting. Urbanline Composite products are virtually maintenance free. They need only periodic cleaning to keep them looking great.
Cost of Maintenance Periodic expense – purchase of timber coating products.Depending on the site installation, cost of scaffolding, cost of the inconvenience of restricted access i.e. wet coating on decking etc. Very minimal. Mostly, a wash down with a hose will suffice.
Warranties No warranty. Depending on the product, warranties vary from 10 to 25 years.
Colour Variance Natural colour variance. Dependant on the Composite product. Some Composites are manufactured with natural fibres, which may mean some colour variation between boards and initially, in full sun, the colour will lighten a little. This will stabilise after 8-12 weeks of full sun exposure. The grain direction of some Composites will reflect light differently, depending on the orientation of the boards.
Sustainability / Environment Timber has an excellent sustainability rating and very low environmental impact. This is because the quantity of carbon contained within the wood of the decking/cladding product itself, is greater than the equivalent greenhouses gas emissions throughout its life cycle. Considerable quantities of carbon are also contained within Composite products, but energy use in the manufacture of this product generally results in emissions of greater quantities of carbon, than what is contained in the finished product. Periodic coating/maintenance and timber board replacement on decks and claddings, increases the environmental impacts, however, if the service life of a Composite product is double or even triple that of solid timber the environmental performance measures would nonetheless favour solid timber.
Installation Timber cladding to be installed as per manufacturer’s instructions. Composites to be installed as per manufacturer’s instructions, taking careful note of required clearances etc. The installation of Composites has many similarities with timber installation, including the same tools and equipment.
Life Span In a given site and application, a Class 1 species will last longer than a Class 2 species and so on. It should be noted that a Class 2 species, in a less hazardous situation, might last longer than a Class 1 species, in a different, but more hazardous situation.For each of the four Classes, there is an expected service life range. The above ground ranges are different from the in-ground contact ranges.The relevant Australian Standard AS 5604 provides natural durability ratings for a large number of species, in several categories, including lyctid susceptibility, termite resistance, in-ground contact durability, outside above-ground durability and marine borer resistance. Class 1 rated species are the most durable and Class 4 rated species the least durable.In fairness, sometimes cladding and decking timbers do not live up to user expectations. In most cases, this is not the fault of the material, but rather, a result of a lack of understanding of the various species of timber, their suitability and their installation and maintenance. Plastic and wood Composites are worked similarly to real wood and do not require treatment. They hold up well to water, sun, insects, and salt air – typical enemies of timber.With the Urbanline Duro Composite product, the plastic encapsulates and binds the wood to resist moisture penetration and degradation from fungal rot, bringing together some of the best properties of both wood and plastic.Urbanline Millboard, however, is manufactured from a blended polyurethane and mineral base. In production, it is bonded with a hybrid polymer ‘lastane’ top layer. These advanced and unique materials ensure that you have unprecedented combined benefits, to ensure your enjoyment, safety, and worry-free decking for years to come.The manufacturer limited warranties that support these products suggest years of maintenance free use.
Water Resistance Timber is not water resistant and will expand when wet and contract when drying out. Generally, timber needs to be coated or impregnated with preservatives to give it water resistance. Generally, Composites have excellent moisture resistance (some more so than others). Urbanline Millboard is the amazing Composite decking that is wood free is unaffected by moisture – totally water resistant!
Leaching Some timber species leach. When tannins are washed out of the timber in the rain, it can cause run-type staining on surfaces underneath. Composite products do not leech.
Slip Resistance for Decks Most natural timber surfaces do not meet the non-slip standards and generally require the surface to be coated with a timber slip-resistant coating. Urbanline Latitudes and Millboard products have received very positive anti-slip ratings.
The Bottom Line A robust life cycle assessment indicates that Wood-Plastic Composites have substantially higher environmental impacts in comparison to naturally-durable solid wood products, such as Western Red Cedar. However, the use of real timber does provide a natural warmth and authenticity that Composites find it difficult to match. Wood-Plastic Composites provide an exciting alternative to solid wood for many applications. These products are relatively new, under constant development, and have improved dramatically over the last five years. The main advantage is that they are very low maintenance and, whilst they could never reach the high level of environmental certification of natural timber, they are safe and hard wearing, have a long life span and help conserve the environment by keeping more trees in the forest.

The above information is provided for general education and informational purposes only and does not constitute an endorsement, approval or recommendation of any kind. The actual suitability and applicability of this information for a given use depends upon a host of considerations. These include laws and regulations applicable to the intended use of the information, specific attributes of that use or project, and the specifications for any product associated with this information.