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Efficient use of materials

Construction materials are chosen for a number of reasons, including: 

  • Cost

  • Availability

  • Performance

  • Aesthetic quality

Increasingly, projects are including environmental performance as a specification consideration. The environmental performance of materials can be assessed in a number of ways, these are described in the table provided.  

MaterialExample

Reclaimed/Reused

Reuse of a brick as a brick

Reuse of reclaimed slate tiles on roofs

Recycled

Reuse of a crushed brick as aggregate

Reuse of timber beams as street furniture

Materials with recycled content

Plasterboard that is made with 85% recycled gypsum

Blockwork that is made with 50% recycled aggregate

Environmentally labelled

BRE Green Guide A+ rated materials – the Green Guide provides a simple online guide to the environmental impacts of building materials.

Low embodied energy

Use of plywood boards instead of chipboard

Use of glasswool insulation instead of polystyrene

Locally produced materials

Sand and gravel from available sources in Hertfordshire

Use of UK sources for all other materials

Natural materials

Using natural slate rather than artificial slate

Using thermafleece (sheep wool) or mineral wool rather than foam insulation

Materials with good whole life performance

Use of aluminium faced timber windows rather than PVC windows

Reclaimed/Reused/Recycled materials

Substitution of primary/virgin materials for reclaimed or recycled materials improves the sustainability of buildings by:

  • Reducing the reliance on primary materials.

  • Reducing construction and demolition generated waste, (or waste from other industries if the materials are sourced externally).

A number of material types lend themselves well to reclamation, notably those that have a high economic value or particular aesthetic quality such as:

  • Hardwood flooring

  • Timber structural joists and steel beams

  • Stone (e.g. York stone, limestone)

  • High value cladding (e.g. granite or marble)

  • Brickwork

The Waste and Resources Action Programme (WRAP) provides an environmental rating framework for materials, according to their recycled content. Product recycled content (as defined by ISO 14021), is measured as a percentage of total material mass.

Building recycled content can be calculated using a specially developed software too at WRAP. This link also includes a full database listing construction products that have a high recycled content. 

Many procurers, notably public sector clients, specify a 10% target for whole building recycled content. This target is calculated by product value, rather than mass.

Examples of products that inherently have a high recycled content are listed below. The products listed do not incur additional cost or impact upon other project considerations such as programme, aesthetic quality or functionality.

However, in some instances, products with a higher recycled content raise technical issues. For example the use of cement replacements (e.g. pulverised fuel ash) increases concrete curing time.

ProductTypical recycled contentBest practice recycled content

Plasterboard

36%

84%

Blockwork

0%

90%

Concrete

1) 20% of course aggregate 2) 50% of cement replaced by GGBS*

1) 100% of course aggregate 2) 70% of cement replaced by GGBS (ground granulated blast furnace slag)

Vinyl floor finish

12%

100%

Roof concrete tiles

0%

22%

Mineral/rock wool insulation

25%

50%

Environmental labelling

The Green Guide to specification contains environmental information on more than 1200 materials used in buildings (e.g. for external walls, roofs). It summarises their relative environmental impacts using an A+ to E ranking system, where A+ represents the best environmental performance (least environmental impact), and E represents the worst environmental performance (most environmental impact). The Green Guide is an integral part of BREEAM (the BRE Environmental Assessment Method).

Building type

Category/Element

Domestic

Roof Construction

Pitched roof timber construction

 

Structurally insulated timber panel system with OSB/3 each side, roofing underlay, counter battens, battens and concrete interlocking tiles

Retail

Insulation

Insulation

 

Cavity blown glass wool insulation - density 17kg/m3

 

Building type

Category

Sub category

Element

Industrial

External wall construction

Brick, stone and block work, cavity wall.

Brick or stone block work, cavity wall.

 

Brick on outer leaf, insulation, aircrete, block work, inner leaf, cement mortar, plaster, paint.

Many standard elemental specifications are A rated.

Material

  • Brick outer leaf, insulation, dense blockwork inner leaf, plasterboard. 

  • Aluminium insulated composite cladding, galvanised steel rails, dense blockwork, plasterboard. 

Internal walls

  • Steel/timber stud, plasterboard, wool insulation, paint.

  • Aerated block, plasterboard, paint. 

Roofing

  • Flat roof, inverted deck: Galvanised steel deck, asphalt, insulation, paving slabs. 

  • Pitched roof: concrete tiles, battens, sarking felt, on timber roof structure with insulation between rafters. 

Floor finish

  • Hardboard sheathing, linoleum. 

  • Wool/nylon carpet, natural.

  • Fibre underlay.

Timber certification

The timber industry has developed a number of sustainable certification schemes for individual forests and plantations. These provide independently certificated guarantees that these were managed in a sustainable way (i.e. as per widely recognised sustainable forest management criteria, such as biodiversity, recognition of local community and indigenous right, and so on). The sustainable certification schemes (with a valid Chain of Custody for the product purchased and the appropriate supplier) that are recognised by the BREEAM are listed below:

SchemeRecognised label/acronym

The Forest Stewardship Council (FSC)

logo fsc

Programme for the Endorsement of Forest Certification schemes

logo pefc

Canadian Standards Association

logo csa

Sustainable Forestry Initiative with Chain of Custody

logo sfi

Malaysian Timber Certification Council

logo mtcc

Low embodied energy materials

Embodied energy is the energy used to extract, process and transport a material (from cradle to factory gate). For example, the embodied energy of a brick is the energy consumed by all the processes associated with a brick, from the acquisition of natural resources to product delivery.

Generally, higher mass materials are subjected to intensive manufacturing processes and require extensive transportation energy (e.g. HGV diesel); they therefore have higher embodied energy. However, embodied energy can be offset by using materials with a higher recycled content.

The following tables denote comparison examples of different options by material type (insulation) and by function (structure).

Materials - solutions - low embodied energy materials

Materials - solutions - low embodied energy materials 2

Local materials

The use of local materials presents three notable benefits: 

  • Support for the local/UK economy and skilled tradesmen.

  • Reduced environmental impact associated with road haulage.

  • Aesthetic qualities that complement local character distinctions - Hertfordshire is known for its weatherboard cladded houses and chiltern brick.

Natural materials

Natural materials typically have a lower environmental impact than synthetic alternatives; however, some can cost more and some have shorter lifespans. Example products and associated impacts/benefits are set out in the table below.  

Standard productImpacts and benefitsNatural alternativeImpacts and benefits

Chemical based paint

Production includes complex chemical processes and can be toxic during manufacture and application

Low VOC paint – water and vegetable oil based paints

Has low embodied energy and mostly non-toxic

Foam insulation

Good thermal performance and less thickness is needed, but produces toxic substances in combustion

Wool insulation

Can be 100% natural (sheep wool) and provide good thermal performance

Chipboard

Has high chemical and adhesive content, but contains recycled timber chippings. Difficult to recycle.

Compressed timber composite (plywood, softwood)

Has no chemical content and provides a good base for finishes

Reconstituted slate

Has high chemical content and high embodied energy but low cost and easy to install and maintain

Natural slate

100% natural material with no chemical content. It is non-combustible, resistant to acids and highly durable

Whole life performance

The whole life performance of a material is the performance of a material (or building) over a defined period of time. Typically building performance is measured over 60 years. Whole life performance takes into account the following issues: 

  • Capital costs
  • Maintenance, replacement and repair costs
  • Facilities management costs
  • Disposal costs

Whole life costing analysis measures the economic impact of a built asset over its life, taking into consideration design, construction, installation and operation of building systems; rather than focusing solely on initial capital costs. 

Whole life considerations also impact upon the selection of materials with low environmental impact. For example, high mass external wall cladding options such as brick have a higher direct environmental impact than light weight timber and steel systems. However, they typically have lower maintenance requirements and a longer life, therefore their whole life costs are lower. 

Often, whole life costing analysis demonstrates that investing a little more initially can present very favourable lifecycle savings. Whole life costing analysis is a mandatory requirement in publicly procured projects.

Major lifecycle significant items

Major lifecycle significant items in order of impact are as follows: 

  • Internal finishes consisting of: flooring (carpet, vinyl etc) - walls - ceilings - doors (internal and external)
  • Emergency lights which include their own batteries
  • Fixtures fittings and furniture
  • Automatic building control systems
  • Closed circuit TV systems
  • Heating systems
  • Light fittings
  • External windows
  • Rainwater goods
  • External walls

In some instances, it may be appropriate to select lower grade materials where the building or its fit out is expected to be short term (e.g. retail environments). Items or rooms requiring high levels of maintenance should always be designed so that they are easy to access.