WELL Building Standard

What is WELL?

The WELL Building Standard is a performance-based certification system focused exclusively on the health and wellbeing of building occupants. Developed by the International WELL Building Institute (IWBI), it assesses buildings across ten concepts: Air, Water, Nourishment, Light, Movement, Thermal Comfort, Sound, Materials, Mind, and Community.

Unlike BREEAM or LEED, which assess broad environmental sustainability, WELL focuses specifically on how a building affects the people inside it. Material choices are directly relevant to several WELL concepts - particularly Air (VOC emissions), Sound (acoustic materials), and the dedicated Materials concept.

WELL v2 is the current version, with certification levels at Bronze, Silver, Gold, and Platinum. It is increasingly specified alongside BREEAM or LEED, creating a dual certification that addresses both environmental impact and occupant wellbeing.

The Materials concept

WELL v2 includes a dedicated Materials concept (X06-X14) that addresses material transparency, chemical hazard reduction, and responsible sourcing. This is where material specification has the most direct impact on WELL credits.

X06 · VOC restrictions

Maximum emission rates for paints, adhesives, sealants, flooring, insulation, and furniture, tested to CDPH or equivalent.

X07 · Material transparency

At least 25% of products by cost disclose ingredients via HPDs, Declare, or Cradle to Cradle.

X08 · Material optimisation

Rewards products third-party assessed to avoid hazardous chemicals - Declare Red List Free, C2C Gold+.

X09 · Waste reduction

A construction waste management plan targeting at least 70% diversion from landfill.

X10 · Responsible sourcing

Credit for FSC-certified timber, EPD-backed products, and manufacturer sustainability commitments.

Note. WELL's Materials concept is the most prescriptive certification framework for material ingredient transparency. It goes beyond carbon and environmental impact to focus on what chemicals are in the products and what effect they might have on occupant health.

Material impacts on air quality

The WELL Air concept contains some of the standard's most stringent material-related requirements. Indoor air quality is directly affected by the materials installed in a building, particularly during and shortly after construction.

Topic	Detail
VOC emissions	WELL sets maximum emission limits for formaldehyde, total VOCs, and individual compounds. These limits are stricter than most building regulations and require product-specific testing
Wet-applied products	paints, coatings, adhesives, and sealants must meet specified VOC content limits (typically aligned with EU Decopaint Directive or stricter)
Composite wood	all composite wood products (plywood, MDF, particleboard) must be certified to ultra-low formaldehyde emission standards (CARB Phase 2 or E1 with additional testing)
Furniture and furnishings	WELL extends material requirements to furniture, which is unusual among building certification schemes

Sound and acoustic materials

WELL's Sound concept (S01-S07) sets performance targets for acoustic comfort that directly influence material specification. Achieving these targets requires careful selection of acoustic absorption materials, sound insulation products, and vibration isolation systems.

Topic	Detail
Background noise	maximum levels specified by room type (e.g. 35 dB(A) for open-plan offices). Requires acoustic insulation and isolation of mechanical equipment
Reverberation time	maximum values set by room type. Typically requires acoustic absorption panels or ceiling tiles with appropriate NRC (Noise Reduction Coefficient) ratings
Sound masking	optional credit for electronic sound masking systems in open-plan environments
Impact sound	maximum impact sound levels between floors, requiring resilient layers or floating floor systems

Practical steps for material specification

These strategies help you select materials that support WELL certification efficiently.

Request VOC reports early

Get test reports at specification stage - not once products are already on site.

Default to low-VOC finishes

Specify low- or zero-VOC paints, adhesives, and sealants for all wet-applied products.

Use the WELL Materials Library

Find pre-verified compliant products at material.wellcertified.com before specifying.

Ask for HPDs and Declare

These labels provide the ingredient transparency that WELL credits require.

Plan a flush-out

Minimum 14 days at specified air change rates before occupancy to reduce residual VOCs.

Favour natural materials

Clay plaster, lime plaster, cork, and solid timber typically have inherently low or zero VOC emissions.

Tip. Many products that meet Greenguard Gold or Blue Angel certification also satisfy WELL VOC requirements. These certifications can serve as a shortcut for compliance checking.