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The amount of recycled and reused materials in a build will affect its environmental friendliness. Both methods will reduce the need for new materials and the associated energy expended in its transport and production as wells as reducing the total waste sent to the UK's landfill sites.
Bricks are one of the most widely used construction materials. Bricks remain durable with age but do change colour over time as they react to sunlight. This effect can be desirable for adding character to a new building. There is a large market in recycled whole bricks.
Re-using bricks from de-constructed buildings will save the creation of new brickwork. When a building is de-constructed the bricks are removed and cleaned up allowing them to be used again just as easily. Re-usable bricks tend to be more expensive than standard new bricks at around £1.10 per brick, and are available in various shades caused by the sun ageing the brick. This is particularly advantageous when building an extension on to a property as a better match of brick can be used to make it stand out less than if fresh brickwork was used.
Recycling brickwork on site will save in transportation costs and landfill fees. Where brickwork is not suitable to be used again as a brick (due to damage or excessive wear) it can be crushed to create a rubble. This rubble can be used as aggregate in concrete, as a base layer in road construction or to provide filler to earth landscaping techniques such as Cornish Hedges.
Bricks can also be made from recycled constituents.
The UK currently uses around 50 million square meters of wood every year, with only 11 million square meters produced within the UK. 70% of the soft wood used in the UK is used in the construction industry. The UK produces around 7.5 million tonnes of waste wood each year of which only around 1.2 million is reused or recycled. When wood is placed in a landfill it decomposes releasing methane gas which is a very potent greenhouse gas and a major contributor to climate change. While wood can be a sustainable construction material it is important to recycle and reuse to help counter the imbalance of wood imported (and therefore transported, burning fossil fuels and releasing CO2) vs. produced locally.
Reusing wood from existing builds allows for a high grade construction quality wood without the need for reprocessing. Often timber based roof supports can be reused as roof supports in a different building. Where damage has occurred or other problems prevent them from being reused wooden supports can be used to create garden fixtures or furniture. Railway sleepers can reused to create garden fixtures such as benches and to provide retaining support for flower beds. Wooden floorboards from an older building, if in a good condition, can be reused in a new building.
Wood should be recycled when the wood is too damaged to be reused. There are a number of ways to recycle wood. Wood can be mulched and added to soil to enrich it and help against erosion. It can be shredded and used in animal bedding (if untreated) or in compost heaps to assist the circulation of air within it. Wood fibres can be recovered to create construction materials such as MDF and chipboard although these themselves are harder to recycle. Where all other options for recycling fail, wood can be burnt to produce energy. While this process releases CO2 it should be noted that trees remove CO2 from the atmosphere during their lifetime and burning wood will save burning another fuel such as coal which only contributes to the level of CO2 in the atmosphere.
Concrete is used extensively on construction projects. The production of concrete requires a lot of heat and energy and so maximising the use of already existing concrete will help stretch the energy involved in its production. Concrete cannot be reused in the same way that brickwork and wooden materials can. Concrete can be recycled by crushing it. The fine concrete dust can be added to new mixes of concrete as aggregate to reduce the amount of new material needed and replace some of the fly-ash used (a by-product of coal fired power stations). Larger coarser chunks of concrete rubble can be used as aggregate in road construction as well as in the foundations of new buildings.
Building insulation can be reused and recycled between builds. This is especially true for wool insulation commonly used in roofs. This can be pulled up from the de-constructed building and relaid with ease. Where artificial wool is used this can save on the production of new man made fibres which create 11,000 tonnes of glass waste during fibre glass production. Plastic and wood based insulation boards which may be difficult to dispose of. Plastic based boards are often rejected by land fill sites. Both can be reused if they can be re cut to an appropriate size.
Surfaces used within a structure can be reused extensively. This includes kitchen surfaces, shelving etc. where it is not possible to reuse these they can be recycled as for wood. Where new fittings are required make sure they contain as much recycled material as possible, this is especially true for kitchen surfaces which are often MDF or chipboard with a thin protective layer on them.
Currently 48% of all flat glass (primarily glazing) ends up in the landfill. Glass from old builds can be reused by refitting existing windows to new frames, where size will allow. Where this is not possible the glass can be crushed down and recycled. When recycled glass can either be used to form new windows or, where quality is an issue, it can be used in other areas of glass use, such as being made into containers. Glass can also be turned into construction aggregate for use in the construction of tiles, roads and even paint (some paints can contain as much as 30% glass). Every tonne of recycled glass used in the production of new glass will save over 300kg of CO2 as well as reducing space taken up in land fill sites.
Plastics rare made from oil, and oil is a finite fossil resource and also require transportation. Plastic does not degrade easily either which means that it will fill space in landfills for thousands of years to come. The production of new plastics also requires a lot of energy and can release pollutants such as dioxins into the environment. There are many different types of plastic making it difficult to know what can be recycled to go into a new material. This means that all plastic waste should be recycled to allow for the maximum potential of it to be reused. PVC window frames can be recycled into new frames using drinks bottles to add to the material where necessary.
Copper wiring and pipework located in and around buildings can be either reused in its current form or can be sent to be smelted down and reused. Copper has risen significantly in price in recent years. Copper mining has a substantial impact on the environment and has been known to cause water table pollution, so reducing the need for fresh material will benefit both a project's finances and the environment.
Tiles and ceramics
Roof and interior tiles are often made from mined stone and require transportation around the world. Roofing slate can be carefully de-constructed and reused in its original form as can some interior tiles. Where tile work has become damage it can be turned into rubble and used as aggregate around a site.
We have used composite roof tiles rather than slate as they are made from recycled materials, cheaper, and thicker so providing better insulation. They look the same as they are a dark slate grey colour.
Worn out vehicle tyres are also a useful material to have on a building site as well as plentiful. 480,000 tonnes were scrapped in 2002 with 80,000 tonnes going straight to the landfill. These can be re-used to build structures by filling them with compacted earth resulting in a strong and fire resistant structure (such as the earth-ship style house). These can also be used when landscaping to help create stable earth banks.
Recycled tyres can also be reduced to crumb through a process of grinding. This rubber crumb can be used to create impact protection for children's play areas as well as being added to the roads of a site to help keep noise levels down.
When building green the first priority of the build regarding construction materials should be to use already existing materials. This is favoured because it reduces the need for using new materials and any excessive fuel miles will have already be done.
An example is imported wood, even though the source forest is sustainable, reusing wood locally saves on having to import new material from hundreds or thousands of miles away.
Where it is not possible to reuse existing materials recycled materials should be used, while often not in the original form (for example as aggregate), every kilo of recycled material will in some way reduce the amount of new material required. It also reduces the amount of waste sent to landfill where it would only slowly rot unused.