- Cement / woodwool boards
- Cement and concrete
- Hemp / lime
Sustainability of building materials
This can have several slightly different meanings which are to do with:
- Whether the material is actually running out or very rare (e.g. Cuban Mahogany)
- Whether the embodied energythe total amount of energy it takes to make a material (or a building). See more on embodied energy of the materials is high or rapidly increasing (e.g. Yorkshire stone roofing slates now mainly come from India!)
- Whether there are other issues which affect the sustainability (for example, though there is plenty of gravel in the ground there is often an environmental problem with extracting it)
Life Cycle Analysis (sometimes known as ‘cradle-to-grave’ or better still ‘cradle to cradle’) is the analysis of a building’s total demands on the environment throughout its whole lifetime, usually measured in terms of energy used but also in terms of how building materials can be reused, or whether, for instance they lock in carbon, as with timber construction.
Greenspec have a good section covering materials.
The BREBuilding Research Establishment. do a free on-line guide called the Green Guide to Specification which rates elements of construction (such as walls, floors, windows etc.) from A++ down to E. It takes into account 13 different environmental factors. These are
- Climate change
- Water extraction
- Mineral resource extraction
- Stratospheric ozone depletion
- Human toxicity
- Ecotoxicity to Freshwater
- Nuclear waste (higher level)
- Ecotoxicity to land
- Waste disposal
- Fossil fuel depletion
- Photochemical ozone creation
and you can see how each element fares by each factor by clicking on it. However there has been considerable criticism of the guide because it doesn’t explain how its methodology works and it does not distinguish properly between embodied energy and in-use energy. The A to E ratings are simply relative ones with no actual values involved. The whole thing is a bit of a mishmash.
Recycled materials and reused materials
Recycled materials are those that are chopped up, melted down, ground down etc. and then made into something else (or maybe a similar thing).
Smile Plastics do a beautiful range of plastic sheets made from all kinds of plastic waste.
- However there is a bit of an issue here with what might be called ‘recondoning’. As with the recycling of uPVC in the window and door manufacturing industry the question arises as to whether oil based plastic should have been used in the first place, considering the risk of pollution from oil mining. Sure, it is better to recycle than to use new material but it would be better still not to have used that material at all.
There’s a growing number of outlets and on-line exchange facilities for reused materials but this is a kind of tricky issue because the way you design a house may depend on what is available at the time. No good designing a roof to use salvaged tiles or slates if they are not available when you need them. Helps if you can revert to a new equivalent if you get caught short, especially if the planners are keen on exactly what gets used. However there can be a good deal of satisfaction in reusing materials; big environmental benefits, connection with the past, and sometimes a more relaxed feeling about not needing to get things perfect.
Reuse and recycling can take several forms:
- re-using materials from a previous building on the site. Examples may include:
- hardcore derived from masonry
such hardcore is typically used for bedding under drives, parking areas etc. but it is important to make sure it doesn’t contain deleterious materials or contaminants. See the Building Regs, Approved Document, Part C
- walling stone
- roof tiles and slates
- windows and doors (this may require careful design for their incorporation)
- timber structural members
- plumbing such as tanks, taps, cylinders, valves etc (providing they are tested)
- electric cable and fittings (provided they are tested)
- hardcore derived from masonry
- buying in reusable materials. This may be desirable / necessary when materials must match up with part of an existing building
- buying in recycled materials. See the section on suppliers
- selling materials for reuse
Salvo has an excellent set of links to various companies which trade in recycled, reclaimed and reused materials
The National Wood Recycling Project is a network of social enterprises which recycles wood and wood products
Inno-Therm manufacture insulation from discarded denim/cotton, such as jeans
SurplusMatch Surplus and discount building materials marketplace
Recipro Online Builders’ Surplus Recycling and Exchange
Tradeleftovers A free site for tradesmen to shift spare materials
EBC UK Ltd do a range of recycled roofing materials including slates and sheets
Gardiners reclaimed building materials – in the Staffordshire area
A good all round book on ecologically sound building materials is ‘Natural Building’
A large data base of building materials and suppliers is available at SpecifiedBy
A particularly good book on the ecological aspects of building materials is ‘The Whole House Book’ (although it is now getting a bit dated on things like the building regulationsThese are the mass of regulations that cover safety, health, welfare, convenience, energy efficiency etc. in the way buildings are constructed. Not to be confused with Planning consent (which is more to do with whether you can put up the building in the first place)).