Sustainable Design

Sustainability is a term that most of us have heard but may not fully understand. There is debate over exactly what the term should mean, but one commonly quoted and generally accepted definition defines sustainability as “the ability to provide for our needs without compromising the ability of future generations to provide for their needs.”

True as it is, this definition is quite benign and it does not convey the reality of the situation. What we need to understand is that, if we manage to achieve a sustainable society, then over the next couple of centuries or so the planet’s resources should be sufficient to continue to support human life here on earth, but if we don’t live sustainably, then by definition it will not. So the stakes are high, but what bearing does this have on the everyday work of the interior designer?

A sustainable future will only come about if we change the way we live and make different lifestyle choices. As designers, we can respond to the sustainability agenda in three basic areas:

Material selection: Sources and provenance, embodied energy, process and transport energy.

Conservation: Conservation of resources, efficient design, specification.

Occupier behavior: How people use the space—for example, provision of a shower promotes cycling or running to work. Staircases rather than lifts promote interaction and health.

Why is sustainability an issue?

Modern man first left Africa well over 100,000 years ago. Human population gradually increased, in a broadly steady manner, until relatively recently (the last couple of centuries or so) when that rate of increase became exponential. During the twentieth century alone, the planet’s population increased threefold from two billion to over six billion.

While our planet was easily able to support the demands of a much smaller and relatively unsophisticated human population in earlier centuries, the developed world today consumes an unsustainable amount of the earth’s natural resources. It is only because the majority of the world’s human population currently take proportionally less from the planet than the developed minority that serious problems are not yet a part of our day-to-day experience.

However, as the number of countries that are classed as developed grows, and as emerging nations reach higher up the development ladder, that minority of the population (currently around 20%) that take the majority (typically 75%) of resources will increase in number. Studies have shown that as countries become more developed (and more industrialized), damage to the environment increases.

In short, our increasing consumption of the earth’s natural resources is not sustainable; we cannot continue to exploit those resources (such as crude oil, which is processed into a huge array of products) at an increasing rate and expect all our wants to be met.

The reason that this is of concern to interior designers is because the construction and day-to-day running of a building consumes a great deal of energy and resources. Through the choices that they make when fitting out or refurbishing a building, designers will have the opportunity to affect, for better or worse, the environment. As designers, our answer to the problem should be that for every project we undertake, we pledge to minimize the impact on the environment of that project through the choices that we make.

Although the subject of sustainability is presented here as a chapter in its own right, designers should understand that thinking about (and acting upon) sustainability issues needs to be an integral part of the design process. They must consider the possibilities for creating lower impact interiors all the way through the project; it must become just as much a part of the job as space planning, accessibility issues, or sourcing, and not just an “add-on” that is considered after everything else.

Where choices are made

Choices regarding sustainability can be made at the building structure level (when creating new-build structures or when refurbishing existing ones); when deciding on appropriate furniture and fittings for a design proposal, and even in the choices of surface covering and finishes when dealing with a decorative scheme, as described below.

Building construction practices

Building technologies of the last few decades have made full use of modern materials. Unfortunately, what drove the development of many of these technologies was performance and speed of construction; sustainability was not an issue. Consequently, many existing structures have been constructed with materials that have poor environmental credentials, and the buildings that they have been used to create were not designed to minimize the consumption of energy in their day-to-day use.

New buildings

Materials such as reinforced concrete, for example, are ubiquitous in modern construction, yet the production of reinforced concrete elements of a building, whether in situ or off-site, takes no account of their disposal once the useful life of the building has passed. This means that demolition can be time-consuming, costly, and damaging to the environment, and it can be difficult to reuse or recycle the materials afterward.

Modern construction that does consider sustainability will, first of all, promote the use of materials that have minimal impact on the environment (commensurate with engineering performance), and they will be used to construct buildings which themselves use reduced amounts of energy. Some of the strategies employed to reduce energy use are very simple and in fact refer back to pre-industrial architectural ideas for their inspiration. For example, using greater amounts of insulation will help reduce heat loss when external temperatures are below those of the interior; it also reduces internal heat gain when external temperatures rise. Having opening windows on opposite aspects of a building can promote cross ventilation that can make buildings comfortable when external temperatures are raised. These very simple approaches to making the interior environment habitable have often been overlooked as emphasis has been placed on mechanical ventilation systems and air conditioning to create comfortable spaces that do produce the desired result, but at great cost in terms of energy use.

Alongside the use of these traditional strategies for managing the indoor environment, using traditional materials can promote a healthier indoor environment. The air we breathe inside buildings has become polluted from the effects of a reliance on modern, often synthetic, materials. Synthetics, derived from oil (and therefore not sustainable themselves), are prevalent in many floor coverings, wall coverings and paints; they are also within the resins and adhesives that are used in the production of materials often used in furniture construction (such as plywood and MDF), insulation materials, and so on. Potentially toxic substances can be off-gassed by synthetic materials, and it is these toxic compounds that gradually accumulate in our bodies. Our understanding of the effects of this is not complete, but concerns have been expressed about the long-term health consequences. Traditional paints and surface finishes that predate the introduction of synthetic compounds use mineral or plant extracts that significantly reduce or completely eliminate this toxic element of our interiors.

Synthetic materials

Additionally, synthetic materials are generally not “vapor-open”; that is, they do not allow moisture to be absorbed and released, so they trap moisture within the space, forcing it to condense out on wall surfaces, giving rise to high humidity in kitchens and bathrooms and further problems such as mold.

The natural alternatives to synthetics are usually vapor-open materials (for example, clay plasters, wood fiber, hemp or sheep’s wool insulation, mineral and natural paints, etc.) and are undamaged as they allow moisture to pass through, thereby regulating the humidity of the interior. Research has shown that these materials are several times more effective at dealing with indoor humidity than mechanical ventilation.

New, more stringent, and ever-evolving standards of building energy performance are employed by architects to manage the energy use within new buildings. In some parts of the world, there is a growing trend for residential developments to be constructed such that they use no additional energy at all for space heating. Instead, these “Passive House” standards (there are different definitions of this standard that go by similar names and that are broadly similar in intent) rely on the heat produced by the buildings’ inhabitants during their normal day-today activities, by waste heat generated from lighting, IT, TV, and other domestic electrical appliances, and by cooking, to heat the space. Successful examples of these houses can be found in parts of Europe and North America where snow and freezing temperatures are common during the winter, and the external temperatures are uncomfortably high in summer. Unusually high thermal performance like this is the result of careful construction that not only uses increased amounts of insulation but also practically eliminates drafts through “airtight” construction. In these buildings, ventilation is very carefully managed (with much more efficient systems than standard air conditioning), and heat exchangers are used to transfer heat from outgoing to incoming air to maintain the internal temperature. The theories behind Passive House construction might seem contrary to the principle discussed earlier, which referred to a return to simple traditional practices in building design and ventilation, but they do represent another valid approach to the overall reduction of energy use in our buildings.

Building refurbishment

Building a completely new structure allows us the opportunity to employ techniques that will provide the best sustainable solution, such as those described above. However, while it is useful to understand the principles, the interior designer is unlikely to have much involvement over what is, essentially, an architect’s work.

Working within existing buildings still provides the designer with many opportunities to reduce the energy requirements of that building and improve its environmental performance. In fact, a growing trend is for designers to take the opportunity (where time, budget, and the will of the client allow) to upgrade as much of the infrastructure of a building as possible at the same time as working on new planning solutions and decorative schemes. The vast majority of our existing building stock will still be standing several decades from now, and most of these buildings would allow us to live and work more sustainably if some degree of retrofit was undertaken.

It may well be feasible to utilize many of the sustainable materials mentioned when discussing new buildings above, and so the majority of the sustainability benefits obtained there can also be found in retrofit projects, though the scale of their use may not be so great.

Generating energy

The discussion so far has concentrated on reducing environmental impact through the use of natural materials and also reducing energy use through high levels of insulation, and so on. Most of us will be aware that there are many systems on the market that allow energy from renewable sources (for example, wind, solar, ground heat, and hydro) to be harvested to generate electricity for use in the home, or to heat water directly; many architects and designers are specifying such systems in a bid to improve the environmental performance of their projects.

There is, however, growing concern from some architects and designers that these “environmental fixes” are being applied in situations that are not appropriate and without proper and careful consideration of the consequences. For example, fitting a small-scale wind turbine to a domestic property may seem on the face of it like a good idea, but in reality the vast majority of homes are built in areas where the average annual wind speed is simply not high enough to make these devices work efficiently. Consequently, clients quickly become disillusioned with the technology when it doesn’t work as advertised, which in turn leads to a poor reputation for the technology, and there is ultimately a higher cost for the environment than if the technology had not been employed in the first place. The late Howard Liddell, an architect with decades of experience in sustainable design, counseled vociferously against the indiscriminate use of “eco bling,” arguing instead for an “eco-minimalist” approach where the basics (insulation, draft proofing, etc.) must be taken care of before any attempt is made to apply green technologies for generating electricity or harvesting energy through other means.

Sourcing

If one of the major aspects of an interior designer’s role is finding the materials, furniture, fittings, and so on that will go to make up the interior scheme, then it follows that the designer has a lot of control over the choice of sustainable products. There are different strategies that can be employed when looking to source and at the same time reduce the environmental impact of what is being sourced.

One axiom to be adopted when sourcing is “reduce, reuse, recycle.” This is an approach that neatly leads to the best possible sustainable result. The designer should always be asking questions about the suitability and practicality of any item or material under consideration for a scheme.

The question of permanence is also of relevance—should the designer specify items that could, in time, become heirlooms? Quality pieces, passed from one generation to the next, will clearly reduce the amount of furniture consumed. Thinking long term can be just as important as ensuring that the client’s needs are met in the short term.

Trying to ascertain the environmental credentials of products or materials can be difficult; it is still not as easy as it should be, but this is gradually changing for the better. Enlightened suppliers and manufacturers who don’t have anything to hide are more likely to provide information on environmental performance or history, sometimes in the form of a life-cycle assessment that details the environmental impacts associated with all stages of a product’s life from “cradle to grave.” As this information is usually not independently produced, it is probably best to maintain a degree of healthy skepticism when dealing with these, but they can be useful nonetheless.

Materials— some thoughts

The use of almost any material within a scheme is going to impact the environment in some way. Natural materials, such as wood and stone, are used for many reasons, not least because of their looks, but acquiring these materials can put a strain on the local environment.

Stone

Variations in the patterning of stone occur wherever these materials are found, and particular variations that are sought for their decorative effect can be extremely localized. Some of the most sought-after examples are now reaching exhaustion in the quarries where they originate and once they are used, they are gone forever. When stone is quarried, it is sawn to size and often polished to bring out the pattern inherent in the material. Both of these operations require large amounts of water to cool the saw blades and polishing machinery.

Timber

Many hardwoods are also sought out for their decorative qualities. Some highly desired timber species are vulnerable to extinction, and it can be very difficult to be sure of the provenance of much of the timber that is used for construction and decorative purposes. However, schemes do exist that ensure the timber is grown and harvested in a responsible manner; the timber is then tracked to market, ensuring an unbroken “chain of custody” from source to customer. The most widely recognized of these is administered by the Forest Stewardship Council, and timber bearing the FSC mark is available ever more widely. The Good Wood Guide from Greenpeace provides information on the status of particular species and suggests alternatives for those timbers that are endangered in some way, and it can easily be accessed via the Internet.

Plastics

Most plastics available today are derived from oil—another nonsustainable resource. Although we dispose of huge amounts of plastic, an increasing amount is being recycled, and products made with recycled content are often indistinguishable from those made with virgin material. Still, many designers will choose to avoid plastics if other suitable materials exist, but sometimes it is the case that plastics are the most suitable in some circumstances—this is a choice on which the designer will have to come to their own conclusion.

Other materials

Other materials will have their own considerations—experience will help the designer in determining what to look out for when sourcing, but research may be needed to ensure environmental compatibility.

Thomas Dieben is a designer at Denieuwegeneratie a young Amsterdam-based design studio in Holland. The Dutch Mountain House was their first project.

Was the decision to partly bury the building due to a sustainability agenda or planning regulations?

→The central idea of burying the house was a contextual decision—we didn’t want to disturb the open forest plot too much. The regulations didn’t allow for a two-story house, but by lowering the ground floor half a level, we could fit in two layers, with the entrance on the highest level.

This is a really striking project and, due to its nature, tends to focus on the interior, which is quite pared back and doesn’t feel traditionally “eco.” What was your rationale for this?

→The interior was created as a cave-like open space, almost carved out from the enclosing shell leaving the disposition of rooms, light, and materials mostly flexible, which allows the house to be altered without any issues for years to come. It can still be read in the materials and connective details. The outer shell is kept clean with unfinished concrete; within this, the rooms are defined by lightweight wooden structural boxes with different finishing materials chosen by the clients.

In some respects, the interior seems to curate their collections. Was this an important part of the design process?

→The clients were strongly involved in the design of the interior. Lucas, the owner, is an art historian and collector of both African art and vintage artifacts. His extreme taste is a reflection of his personality. All we had to design was a house that could work as a canvas for their personality. Many, if not most, of the striking interior jokes, such as the bookcase in a car interior, sprung out of the resident’s imagination.

What was your attitude to materials on the project, particularly the concrete, which is not generally considered to be an ecologically sound material?

→As a material, concrete has quite a big carbon footprint. The energetic advantages it has as thermal mass in an embedded context are actually unrivaled by other choices of structure. This is exemplary for the discussions that were part of this project: what do we consider more important—energy or material? In this case, the energy won since the energetic advantage is a longer-lasting advantage. This is a hard but necessary discussion. It puts the complexity of sustainable design in perspective. It forces you as a designer to take stand: do not try to solve everything at once.

What was your overall attitude to sustainability? Was this dictated by energy performance, low carbon footprint, or recycling?

→We have tried to insert sustainable thinking in all levels: context, volume, orientation, architecture, materials, installations, and energy use.

Although we started the design with a high-tech attitude, we ended with a preference for low-tech solutions. We recognized during the design phase the domination of energy thinking in sustainable design and wanted to counter it with architectural thinking: flexibility and contextuality.