Composite Decking as Sustainable Alternative to Timber Decking in Sungei Buloh Nature Reserves

Intro / Background

This report has been developed in response to the request for proposals on developing solutions for engineering problems.

In 1993, Sungei Buloh (SB) Wetland officially opened as a nature park. Subsequently renamed SB Wetland Reserve to reflect its nature conservation status. SB is a mangrove swamp rich in biodiversity and it also acts as a carbon sink making its conservation important. Managed by the National Park Board (NParks) of Singapore, NParks has continued its efforts in conserving and expanding the wetlands with multiple public trails and an education centre.

To support the extensive trails wood decking are used for the boardwalks. Lumber was the material of choice as it assimilates well to the mangrove and is solid structural material. Lumber was also made viable from the 2000s to mid 2010s with its affordable price only surging in recent years as seen in Figure 1 (Trading Economics, 2021). However, the timber decking is deteriorating over the years cracks, splints and holes have been noticeable; the wear and tear has led to fragility of the decking which could be unsafe as such an upgrade should be carried out. The continuation usage of wood for refurbishment is not environmentally friendly or sustainable in the current age, and does not align with the intended NParks goal for a nature reserve to conserve nature and mitigate environmental impact.

Figure 1

Globally, there is an increasing demand for wood products but the supply is starting to dwindle due to the depletion of forest; as of 2016, “Brazil has only 16 years of timber forests remaining, South Africa 7 years, Colombia 12 years, Mexico 9 years, Nigeria 11 years, Thailand 9 years and Pakistan 10 years” (World Wildlife Fund, 2016, para.5). Due to poorly-managed forest with impulsive harvesting has led to an alarming rate of deforestation causing a rise in wood scarcity (Extreme, 2019). Therefore, it is not in NParks interest to continue the usage of wood decking for expansion or upgrade of SB.

With today’s technology, a viable alternative to wood decking would be composite decking. Composite decking are decking boards comprising of reclaimed wood and plastic film; the materials are from post-industrial and post-consumer sources allowing the deck boards to be made entirely out of recycled material (Trex, n.d.). As composite decking does not require painting and sealing which uses harmful or toxic chemicals, it continues to reduce environmental impact even after installation (Preece, 2019). Keystone (2019) also mentioned that the average lifespan of wooden decking is about 10 to 15 years whereas a composite decking has a minimum lifespan of 25 to 30 years. Even though it is much pricier to use composite decking, composite decking has a longer lifespan and higher durability as compared to wood but most importantly sustainable for the environment.

Knowing the current impacts in the wood industry, as a nature reserve, SB should source and incorporate materials such as composite decking in their renovations and development of the wetland. The continuation of usage of wood is not sustainable in light of mass deforestation, a changing climate also reduces the longevity of wood. Therefore, there is a need for alternative material that is not only durable but environmentally friendly.

Problem Statement

As a nature reserve set-up in 1993, SB boardwalks are due for renovation due to the degrading nature of timber planks; but in a deforested 21st century, wood has become a scarce resource. A sustainable solution would be to use composite decking made out of recycled plastic and wood.

Purpose Statement

The purpose of this report is to propose to BCA and NParks the adoption of composite decking as a sustainable solution when upgrading and expanding SB boardwalks.