What Biophilic Design Gets Wrong About Healthy Materials

Biophilic design has moved from niche concept to mainstream specification language remarkably quickly. Walk through almost any premium residential, hospitality or workplace project brief today and you will find it: living walls, natural timber, stone surfaces, indoor planting, views of greenery, references to circadian light.

The intent is right. The evidence base supporting human connection to nature in the built environment is substantial and growing. Lower stress, better cognitive performance, reduced blood pressure, faster recovery times — the case for designing with nature in mind is not a wellness trend. It is increasingly well-supported science.

But there is a problem that the biophilic design conversation has largely avoided.

Looking like nature and being biologically healthy are not the same thing.

The Gap Between Aesthetics and Biology

Biophilic design is, at its core, a sensory and psychological framework. It describes how the presence of natural elements, patterns, materials and spatial qualities can support human wellbeing by meeting our evolved need for connection with the natural world.

What it does not do, systematically, is assess whether the materials being used to create that connection are themselves healthy.

This is a significant blind spot — and it matters to anyone specifying a project where genuine occupant health is part of the brief.

A timber-look vinyl plank floor is not biophilic in any meaningful biological sense. It mimics the visual pattern of wood grain whilst off-gassing volatile organic compounds (VOCs) for years after installation. A limewash-effect synthetic paint layer introduces a natural aesthetic while potentially releasing plasticisers and solvents into the indoor air. A "living wall" maintained with synthetic fertilisers and systemic pesticides brings visual connection to nature whilst quietly degrading the indoor environment it was meant to support.

None of these fail a biophilic design checklist. All of them can undermine the health outcome the biophilic intent was supposed to serve.

Why This Happens

The field of biophilic design has developed largely through the lens of environmental psychology, architecture and urban design. Its frameworks — from Stephen Kellert's six design elements to Terrapin Bright Green's 14 Patterns — focus on spatial experience, sensory engagement and the quality of the human-nature relationship.

Material health sits in a different discipline: indoor environmental quality, Building Biology, toxicology and material science. These two bodies of knowledge have not been well integrated.

The result is that a project can achieve high marks for biophilic design while still creating an indoor environment that performs poorly on material transparency, chemical exposure and indoor air quality.

This is not a criticism of biophilic design as a discipline. It is an observation that the framework, as most practitioners apply it, is incomplete when the goal is genuine occupant health.

Where the Specification Gets Complicated

The challenge shows up most clearly in three areas.

Natural-looking materials that are not natural

Timber-effect products — vinyl flooring, HPL panels, printed laminates over particleboard — dominate the specification market because they are cost-efficient, durable and, increasingly, visually convincing. They are regularly included in "biophilic" interiors because they satisfy the visual criteria.

But the substrate matters. Particleboard and MDF cores often contain urea-formaldehyde adhesives. Vinyl products contain plasticisers including phthalates. Synthetic surface coatings introduce their own compound load. The visual reference to nature is present. The material health outcome is not.

"Natural" materials that carry their own risks

The alternative — using genuinely natural materials — does not automatically resolve the problem either. Solid timber, for example, can be finished with coatings that are high in VOCs. Stone can be sealed with synthetic compounds. Natural wool may be treated with mothproofing chemicals. Clay plasters can contain additives. Bamboo products are frequently bound with formaldehyde-containing adhesives.

The category "natural material" is not a reliable indicator of indoor air quality performance. What matters is the complete specification: the material itself, how it was processed, what it was treated with, how it is installed and how it will perform during its working life.

Living elements that introduce their own exposures

Indoor plants and living walls can genuinely improve air quality, support psychological wellbeing and contribute to the sensory richness of a space. They can also introduce moisture, mould and microbial risk if the system design, substrate and maintenance regime are not considered carefully.

The same living wall that provides a striking focal point and earns biophilic design recognition can also create ongoing moisture issues affecting the broader indoor environment — particularly in buildings with limited ventilation capacity or inadequate moisture management.

The plant is not the problem. The system design, the maintenance contract and the broader building context determine whether the living element actually supports health.

What WELL Certification Does and Does Not Cover

WELL Building Standard addresses both biophilic design and material health, but separately and with different levels of rigour.

The Biophilic Design Certification pathway within WELL rewards connection to nature: views of nature, natural patterns, dynamic and diffuse light, presence of water, living systems and natural materials. It is a meaningful framework for ensuring that projects actively consider the human-nature connection.

The Materials concepts in WELL address restriction of hazardous substances, transparency in supply chains and optimisation of material health. This is a substantive body of requirements — but it applies to materials broadly, not specifically through the lens of whether those materials are being used in a biophilic context.

A project can earn WELL biophilic points whilst also using synthetic materials that do not meet the WELL Materials requirements, if those materials are not among the specific product categories assessed. The two pathways do not automatically cross-reference.

For professionals specifying projects where both biophilic intent and material health matter, WELL provides a useful framework — but it requires active integration across the two concept areas, not passive assumption that one covers the other.

What Genuine Biophilic Design Requires

If the goal is to create spaces that are both sensorially connected to nature and biologically healthy, the specification process needs to hold both criteria simultaneously.

This means assessing materials not only for their visual, tactile and sensory contribution to the biophilic brief, but also for:

• Their chemical composition and any substances of concern
• Their off-gassing profile over time, particularly during and after installation
• The adhesives, finishes, coatings and treatments applied in processing and installation
• Their moisture performance and any associated microbial risk
• Their interaction with the building's ventilation capacity and indoor air quality system
• Their maintenance requirements and what those maintenance inputs introduce into the space

It also means being precise about what "natural" means in a specification context. Natural origin is a starting point for investigation, not a conclusion. Genuinely natural materials, specified with care and installed correctly, can perform extremely well across both biophilic and material health criteria. But that outcome requires informed judgement, not assumption.

The Opportunity for Design Professionals

This gap represents an opportunity for professionals who understand both sides.

Biophilic design is increasingly mandated or encouraged in premium residential, hospitality, workplace and wellness-led projects. Client demand for spaces that feel connected to nature is genuine and growing. At the same time, client awareness of material health, indoor air quality and building biology is also increasing — particularly among clients commissioning premium projects.

The professional who can bring these two bodies of knowledge together — who can specify biophilic elements that are also materially sound, who can brief a living wall installation that genuinely supports rather than compromises indoor environment quality, who can distinguish between a natural material and a natural-looking material in a specification — is providing a service that most current practices cannot offer.

That is a commercial differentiator. More importantly, it is a better outcome for the people who will live, work and recover in those spaces.

A More Complete Approach

Biophilic design and healthy building practice are not in tension. They share a foundational concern: the wellbeing of the people who inhabit built environments.

What they need is better integration at the specification level — a more rigorous approach to material assessment within the biophilic brief, and a more active use of biophilic design principles within healthy building practice.

The question to ask at every specification decision point is not only: does this element connect occupants with nature? But also: does this element support the health of the people it is meant to benefit?

If the answer to both is yes, the project is doing what biophilic design was always intended to do.

Annie Scog is a healthy-building educator and consultant working at the intersection of material health, building performance and human-centred design. She is the founder of Healthy Home Expert and the creator of the Certified Healthy Building Professional program.

If you are a design or building professional wanting to develop greater literacy across materials, indoor environmental quality and occupant health, the Certified Healthy Building Professional program provides an integrated framework for practical application across real projects.