Materials for interior walls, floors and ceilings

 Materials for interior walls, floors and ceilings

Materials for interior walls, floors and ceilings

Some materials commonly used inside your home can contain chemicals that can harm your health.

Common materials for walls, floors and ceilings include:

  • timber — sheets and veneers including plywood and particleboards/MDF, strip flooring, mouldings, benchtops and architraves (solid timber, melamine and MDF)
  • concrete — polished slabs for floors
  • fibre cement — wet area linings
  • plasterboard
  • ceramic tiles for floors and walls
  • stone
  • floor coverings such as carpet (synthetic and wool), linoleum, vinyl, cork, sisal, coir, and bamboo.

To protect your health and minimise harm to the environment, look for materials that:

  • are durable
  • don’t emit volatile organic compounds
  • can be recycled
  • are made from sustainably sourced natural materials or from recycled materials.

Toxicity, emissions and air quality

Volatile organic compounds

Volatile organic compounds (VOCs) are chemicals that become airborne (and therefore breathable) at room temperature. VOCs can have health effects — for example, some VOCs have been linked to asthma.

VOCs are commonly found in:

  • Carpets, carpet backings and underlays (common VOCs in these products include formaldehyde, toluene and vinyl chloride).
  • Treatments for stain-resistance and insect-resistance in carpets.
  • Carpet glues.
  • Vinyl flooring.
  • Timber flooring on concrete.
  • Engineered timbers such as plywood.
  • Reconstituted wood products such as MDF and particleboard.
  • Finishes such as polyurethane and paints.
  • Plastic wallpapers.

To minimise your exposure to VOCs:

  • Look for carpet backings and underlay made of felt, natural latex or jute rather than foamed polyurethane.
  • Look for water-based or acrylic-based adhesives.
  • Look for natural finishes, or finishes that are water-based or acrylic-based. Even products that appear natural — such as bamboo, wool and wood may have finishes that emit VOCs. See Painting and decorating for more about what to look for in paints and finishes.
  • If you’re considering flooring or other surfaces made from engineered timber, or reconstituted wood products, look for products with low emissions. Any product made from engineered timbers should be covered or sealed to minimise emissions of VOCs. Manufacturers often recommend that these products must be encapsulated.
  • Consider options such as ceramic tiles, polished concrete, and linoleum — these have low emissions of VOCs. Natural timber flooring with a low-VOC or natural finish is another option.

Wool scouring and dyeing

Significant amounts of metal compounds and chemicals may be used during the wool scouring and dyeing processes of carpet manufacture. While the residual levels of these compounds/chemicals may be low in the finished products, the waste streams from processing can be highly toxic to workers and waterways. Textiles using plant-based dyes are preferable, but not widely available.

Recyclability, re-use and waste minimisation

Recycling and safe disposal

Depending on the finish and backing, wool carpet can be recycled or safely disposed of in landfills. If it has a natural backing it makes great weed matting.

Linoleum, made from linseed oil, pine resins, limestone and wood flour rendered onto a natural jute backing can be composted or incinerated safely at the end of its life. Note that very old linoleum may have asbestos in the backing and must be removed by a specialist removal company.

Gypsum plasterboard has good recycling potential — used plasterboard can be recycled to make new plasterboard (although not currently in New Zealand), or used as a compost additive. Finely ground gypsum is an excellent soil conditioner.

Minimising material waste

Generally, the more materials you use, the more waste youll produce. For flooring, if you use an insulated concrete slab, polished and sealed, you may not need extra floor coverings.


Wall, floor and ceiling products come from local and imported sources. Plasterboard, timber products, a range of floor coverings, and some ceramic tiles are made in New Zealand. Some of these use raw materials grown or manufactured overseas and imported for further processing.

To ensure materials you choose have come from sustainable sources, look for:

  • information about how much effort the relevant industries are putting into environmental management, natural area regeneration, and minimising effects on local communities
  • independent environmental labels such as Environmental Choice New Zealand — carpets, floor coverings, plasterboard and paints endorsed by Environmental Choice are available on the New Zealand market
  • evidence of environmental management standards (such as ISO 14001, Enviro-Mark®) and environmental management systems such as Zero Waste, EBEX 21, The Natural Step
  • look for wood components that are certified as coming from a sustainable source. See Decking and outdoor furniture for more about timber certification schemes.
  • information about how much effort the relevant industries are putting into environmental management, natural area regeneration, and minimising effects on local communities.


Products such as bamboo, coir (from coconut fibre), sisal, cork, jute, wool carpet and timber should be from renewable, sustainably managed sources. Linoleum also has a high level of renewable components.

Products with components from non-renewable (but plentiful) natural sources include tiles, plasterboard (paper, gypsum), fibre-cement, concrete and stone/stone composites.

Vinyl products are based on non-renewable chemical compounds, as are synthetic carpets — although carpet products can have a high recycled content.

Efficiency and functionality

Energy efficiency

Some floors and walls – concrete, stone, brick and tiles — act as a thermal mass in your home. They absorb heat during the day and release it later when the temperature drops (see Thermal mass for heating and cooling for more information). These features, together with passive heating design, keep inside temperatures warm and stable.

It is worth considering the ongoing benefits of a thermal mass floor or wall, when you are making decisions. While a thermal lass option may seem expensive, a cheaper option may end up costing you more in heating costs in the future.


Heavy materials such as concrete, stone and tiles are very durable and should need little maintenance.

Softer materials such as carpets and coverings made from plant fibres will not last as long, need regular cleaning and may need more regular replacement — so it is important to consider how easy that is to do, and how the product will be disposed of. Check how different carpet construction (eg loop versus pile) can affect durability and ease of cleaning.

Hard flooring and walls may need covering or treatments to ensure durability and reduce the need for regular replacement. Linoleum is a hard-wearing and durable floor-covering that needs no extra treatment once it is laid. However, you should never cover a floor or wall that is intended to act as a thermal mass – this will stop it from absorbing any of the sun’s warmth (for more information, see Using thermal mass for heating and cooling) .


Maintenance for durability is usually a consideration for products with natural components. Think about:

  • the need for treatments, finishes and coatings for protection against moisture and insects
  • the use and disposal of maintenance products that are potentially harmful to you, or the environment
  • whether regular maintenance is needed for ongoing durability.

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