Materials: timber flooring Sustainable wood flooring: an analysis

Sustainable wood flooring: an analysis

Peter Kaczmar examines the meaning of ‘environmentally sustainable’ wood flooring.

Select cask oak flooring. Photo: Jeffreys Interiors

“For timber flooring to be considered as truly sustainable, its in situ service life must exceed, or at least equal, the time taken for the wood from which it is made to have grown in the first place.”

Timber flooring has enjoyed a strong market position over the past two decades and much of the rationale behind this has been due to its unique visual appeal as a naturally sourced building material. However, more recently, and increasingly, the use of timber floor coverings has been advanced on the grounds of its environmental credentials.

Environmental sustainability

Converting a log to boards generally uses little energy and produces less toxic pollution to the environment than the production of most other construction materials, although the extent of transport, drying, machining and coating required, together with the maintenance demand of the end product, all have an obvious bearing on its total embodied energy.

The ‘environmental’ dialogue has shifted away from notions of embodied energy to those of ‘sustainability’, principally motivated by the need to maximise carbon sequestration in harvested products within the built environment.

Daly’s principles

Sustainability is the ability to continue a defined behaviour indefinitely. However, this definition, in the context of the built environment, makes little or no allowance for the environmental impact of that behaviour. This has subsequently led to the concept of ‘environmental sustainability’ based on pioneering work by Herman Daly1 who, in 1990, proposed that:

1.For renewable resources, the rate of harvest should not exceed the rate of regeneration (sustainable yield);

2.The rates of waste generation from projects should not exceed the assimilative capacity of the environment (sustainable waste disposal);

3.For non-renewable resources, the depletion of the non-renewable resources should require comparable development of renewable substitutes for that resource.

By applying Daly’s principles to the manufacture of solid wood and wood-based floor coverings, the first two principles can be met, some would say, relatively easily by ensuring that >>

all timber used in its manufacture (i.e. during primary and secondary processing) is:

• sourced, harvested and processed using certified and legitimate renewable stocks; • harvested, processed, manufactured and installed using renewable energy sources; • disposed of at end of life in a manner that can be assimilated by the environment.

In today’s parlance, the latter is likely to mean either incineration for energy generation or composting, but only if the amount of carbon released can be demonstrably balanced by the regenerative demands of successive plantations used in the manufacture of any future wood or wood-based flooring products that are used to replace it on a ‘quantum-for-quantum’ basis.

Not all wood flooring will necessarily be in compliance with Daly’s third principle since this will depend on whether all the resources used in its manufacture can be shown to be renewable (and biodegradable). This may include a host of man-made polymers and composites used in the production of multi-layered and engineered flooring, including the adhesives used in its manufacture or indeed the materials going into the production of the seals, lacquers or overlays that are used to finish it. The demands of Daly’s third principle are unlikely to be satisfied by flooring variants whose manufacture involves non-renewable materials such as melamines or non-degradable polymers and composites. In reality, this means that only flooring made from unlacquered and untreated solid wood is likely to come close to satisfying the above principles of environmental sustainability.

Bristol Tectonic™ – FSC®-certified oak flooring at The Cow Shed Restaurant, Bristol. Photo: Chaunceys Timber Flooring

Social and economic factors

Since their original introduction, it is now generally recognised that Daly’s principles do not take account of social or economic factors that a sustainable system, reasonably, should be capable of supporting. This automatically introduces additional pressure on whether a particular commodity can truly be said to be environmentally sustainable since the achievement (and maintenance) of a given quality of life is likely to go hand in hand with regular alterations in lifestyles and/ or local environment. This can be driven by a variety of factors from moving house to fashion or even boredom which, in the case of wood flooring, may prompt its regular and premature replacement before its functional service life has come to an end, as fashions or needs dictate.

This introduces a conundrum in the concept of environmental sustainability in that it exerts additional pressure on Daly’s first two principles of sustainable yield and sustainable waste generation. Expressed in simple terms, for timber flooring to be considered as truly sustainable, its in situ service life must exceed, or at least equal, the time taken for the wood from which it is made to have grown in the first place. By curtailing its in situ service life through premature and/or frequent replacement, a carbon deficit will be produced and any credentials of environmental sustainability of the flooring will be diminished or lost. >>

Cascading timber utilisation

To offset this phenomenon, the concept of cascading timber use can show how to prolong the useful lifetime of the timber from which the flooring was made over and above the time taken for the wood to grow. This can be done through a process of recycling and re-use of the original flooring either by reworking or through its incorporation into new products (e.g. laminated window sections), or even by chipping to be used in the fabrication of alternative building products such as oriented strand board (OSB) or fibreboard. In this manner, end use diversification of a particular wood resource (in this case wood flooring) can be achieved and its useful lifespan extended so as to bring any carbon deficit back into balance and achieve better circularity within the natural carbon cycle.

Summary

Ultimately the level of environmental sustainability that can realistically be achieved through the selection of wood and wood-based flooring depends, in part, on the type of resources and processes involved in making it but, more importantly, on the manner in which it is used over the whole of its life and the time frame during which it can serve a useful purpose. This may or may not involve its incorporation into alternative products whose function differs markedly from that of the original.

Unfinished character B oak flooring hand-finished with Russwood antique hardwax oil. Photo: Russwood Given the pivotal role environmental sustainability has to play in light of our own man-made climatic crisis, today’s producers are eager to make claims of sustainability for commercial advantage which, all too frequently, are themselves ‘unsustainable’ when examined critically. It is not possible to simply brand a product such as wood flooring as ‘sustainable’ without knowing how it will be used, how frequently it will be replaced and, more importantly, how and when it will be integrated into the carbon cycle at the end of its life. n

About the author

Peter Kaczmar Senior Consultant BM TRADA

Further information

To find out more about timber and sustainability, visit www.trada.co.uk/sustainability

Further reading

• WIS 2/3-59 Recovering and minimising wood waste,

BM TRADA, 2020 • WIS 4-31 Life cycle costing, BM TRADA, 2019 • www.ukgbc.org/ukgbc-work/net-zero-whole-life-roadmap-forthe-built-environment • https://woodforgood.com/lifecycle-database

References

1. Daly, H. E., ‘Toward some operational principles of sustainable development’, Ecological Economics, 2:1–6, 1990