Introduction
The definition of the term ‘demolish’ is deliberate and controlled collapse of a structure. During the late 70′s Fred Dibnah became the most renowned steeplejack in Great briBain when his work on demolishing tall chimneys without the requirement for explosives was shown on Television. Fred was an intriguing individual and became famous as a specialist on fixing tall chimneys, so when it came to knocking them down he knew just how to acheive it. He would cut an niche at the base of the chimney, then place wooden props to underpin the structure. By meticulously setting the props, the chimney would be likely to collapse in the right place when the wood was set alight and burned away. Once he was almost killed because he miscalculated somewhat, showing just how risky demolition work really is.
The actual word to demolish only came into being in 1570, and was used there after to mean the deliberate taking down or destroying of a building or structure. Even though in fact the process of demolition, in some mode or other, has been occurring for millenia. Properties were demolished either by natural disruptions of the Planet’s crust or during battles or assaults on villages for as long as there have been buildings. The remaining ruins would be removed and rebuilt or used for other buildings in the area and must be early examples of recycling.
Preserving the Past – Preparing the Future.
To conserve Britain’s tradition of farming the acreage between the established parts of the villages and towns is shielded from growth of urban sprawl. This farm land is called Green Belt and is preserved for farming which is fundamental to the ongoing financial state of the nation. By safeguarding the Green Belt, urban areas are increasingly being squeezed to provide housing, so developers end up being much more resourceful to find acceptable sites.
Britain is a country with an exceptionally dense human population per square mile. The quantity of land available for construction is limited in comparison with other nations. Therefore there’s always a healthy demand for space on which to build. Taking down aged and unused properties and replacing them with brand-new is one way to combat this general shortage.
Land that is disused industrial and commercial sites, but could be polluted with dangerous waste or pollution, are called Brownfield sites. When the land has been cleaned up they can be potentially valuable for redevelopment. Both Glasgow and South Wales produced gardens from disused commercial sites and put in Shopping centres to draw in tourists and generate income.
Greyfield sites are different to Brownfield sites in that they don’t have the environmental problems of dangerous waste material. The term greyfield arises from the large areas of asphalt which often had once been car parks of industrial urban units. Their worth is incorporated in the fact that the commercial infrastructure such as roads, electricity, water supply, sewerage, and gas is already available. These urban areas which become under-utilised or abandoned and therefore are precious mainly because they require little or no remedial work to be renovated. Cities such as Leeds and Manchester have had a massive programme of converting the old warehouses or industrial facilities into homes, retail establishments and eating places, retaining the main shell and renovating the interior into desirable accommodation.
The Demolition Process
Any experienced and professional Nottingham demolition contractor should be able to make an assessment of the following basic items.
The design type and actual physical size of the structure.
What elements have re-use value?
What will the cleared site’s re-use be for?
Where are the waste material by-products going to be disposed?
What steps need to be made with regards electricity, water, sewerage and gas mains.
Hydraulic excavators and bulldozers may be used to weaken the walls at the roots, so the building will topple; at the same time managing the manner and path of the fall. Questions of safety are extremely important, and clean-up strategies are also considered when choosing the way the property will be demolished.
Old fashioned Demolition
At one time the standard means of demolishing a building was quite primitive. After the services were turned off, the men and equipment would probably go in and simply just knock down the walls. Then the entire framework would fall and then the ensuing debris could be piled on lorries and be dumped in land fill sites. Concrete foundations were broken up by pneumatically-driven tools and the site would be cleaned of waste ready for the new work to start. However these days demolition practices are subject to rigorous planning, health and safety and monitoring laws and are hugely controlled by the local council. The way a building is constructed will mean that one segment relies on the other for stability and strength. For example the roof of a building is not really fastened down save for fixing roof tiles with nails to stop them slipping. The rooftop stays in place with its own weight because the beams are laid on the top of the walls rather than being fixed into them as they were in the past for much older properties. The cross beams and purlins then tie the entire thing together to secure the frame of the roof. To this slats are laid as a frame for laying on the tiles or slates. Some other sections of a building are also interdependent so when it comes to demolition these concerns are considered in the sequence of deconstruction. In a sense, like Fred Dibnah you have to be a professional in construction to understand how to perform the deconstruction.
Deconstruction and Recycling
The newest method of demolishing properties is known as deconstruction – an environmentally friendly approach. Landfill sites are in short supply and so the aim when demolishing a property is to minimise the volume of waste materials remaining.
Small constructions for instance two or three storey houses may be taken apart quite easily. The job can be a slow task of dismantling by hand – brick by brick – or beam by beam but by going carefully costly elements are preserved for re-use. The beauty of deconstruction is that 90% or more of waste material is prevented from going straight into landfill sites and reclaimed components can be re-used and recycled for future structures. The farmer opposite my house sold his barns in the farm yard for construction; when the contractor demolished the barns he cleaned up the bricks and reused them to make the walls around the farmhouse hence retaining the character of the farm.
Contemporary techniques and equipment permits demolition firms to effectively segregate waste varieties on or off-site. Building resources are recycled and re-used whenever possible in the new construction creating significant financial savings in project costs not to mention being good for the planet.
Concrete can now be easily cracked using a huge guillotine.
The demolished building can actually be reused by turning it into 6f2 recycled gravel which can be done on site and then utilised as hard core for the new building foundations.
Copper pipes, lead, roof tiles or slates, floor tiles, wiring and doors, and solid wood panelling are valuable objects which can be saved for recycling to be re-used. A lot of specialist companies offer up reclaimed old or classic building items in most towns and cities.
Taller Architectural Structures
Tower blocks and chimneys are the sort of tall buildings that might need to be demolished. The demolition of tall structures requires skilled approaches. The highest building to be demolished lawfully was in 1967/8 for the Singer Building in New York. The collapse of the World Trade Centre after the 9/11 assault in 2001 demonstrates the awful devastation that develops if the demolition is out of control and haphazard.
In the demolishing of high buildings and larger structures a wrecking ball on a crane can be employed, but is rarely used since the swinging ball is somewhat uncontrollable. The closeness of other structures is often a deciding factor which often prevents the employment of explosives to implode a tall building. So ‘High Reach’ demolition excavators are used wherever alternative techniques will not be possible to demolish the top portion of a tall building. Once it is down to a manageable height demolition can continue in the usual way. The various methods of demolishing tall buildings are by implosion using explosives, controlled collapse and piecemeal. To control the dust produced in demolition, water hoses and spray equipment are sometimes used and then it is called a wet demolition.
Explosions
Using explosives in demolition is extremely specialist work and getting it wrong would be catastrophic. If for instance there exists atmospheric pressure from low cloud above the implosion site, the shockwave may spread outwards as opposed to upwards causing the wave of energy and sound to break windows. If the implosion is not prepared correctly the danger may be damage to surrounding buildings where flying debris might cause injuries to spectators.
For many individuals when they consider demolition they might have in mind the employment of explosives in the dramatic collapse of a tall building. This method is in fact called implosion using explosives. Implosion is essential for dense urban areas since it brings down a tall building so the surrounding environment is damaged as little as possible. The collapse takes only mere seconds for the building to fall into its footprint.
Because of the hazards of dealing with explosives they are only used when other methods are too costly or impractical. Where there is a partial collapse of a building and there are still primed explosives that did not go off, workers will be in great danger because the remaining structure is highly unstable. On top of that the demolition needs to continue to secure the safety of the site.
Health and Safety
The work of demolition is a much more technical and complicated process than most people would appreciate. The work is extremely risky and requires experienced and skilled operators to undertake the work. It is essential that personnel working in the market are adequately trained. Health and safety awareness is vital in demolition services so a good idea is for operatives to have gained certificates of Competence in Demolition to guarantee safety for both workers and public alike. All demolition jobs are regulated by way of the Construction, Design and Management Regulations.
The sequence of demolition to follow are prerequisites of work a Nottingham demolition company has to work through to gain planning for your demolition works.
Sequence of Demolition
An incorrect sequence of dismantling can lead to premature collapse of a building because the stability of any structure is reliant on the interdependence of the component parts. Consider a house of cards and what the results are if one of many supporting cards is removed.
There is a strict sequence of events before any demolition can take place. Councils across the country will have their particular specific list for planning approval within their area, but a typical order would be the following:-
Provision of information
Information has to be provided about the design of the structure to be demolished. Details of its previous use as well as the appropriate demolition methods to be employed, including disposal of hazardous substances, have to be submitted by the demolition company.
Survey of Demolition
A thorough survey of the site to identify any structural problems, as well as risks associated with hazardous or flammable substances, will have to be discussed at length with the authorities. (E.g. A disused garage where petrol has been stored is often a potential fire hazard so preventative measures will have to be taken).
Preferred and Safe Method of Work
A good demolition company should be able to select the right way of disposal showing the outline dismantling process. Planning is essential for assiduous monitoring. The authorities will need a detailed statement of the safety procedures to used, and all parties involved need to agree the techniques before any demolition can take place.
Preparation and Planning
Issues such as asbestos abatement, rodent baiting, handling hazardous substances, disconnecting utilities, and making safe any electric, gas or other services must be shown in the planning stage. There is a great deal of preparation to be done before even starting work on demolishing the property itself.
Protection of the Public
Safety can’t be compromised so where there are heavily populated areas surrounding the demolition site the protection of the public is paramount. Any health hazards will need to be assessed and temporary services arranged, and individuals affected must be informed.
Conclusion
The aim in demolition is always to eliminate an unwanted building as safely and quickly as possible also in our modern environment attempts are made to recycle or re-use most of the old material. This isn’t a new idea even though the word itself is relatively modern. On the borders between England and Scotland after the Romans left, a sizable portion of Hadrian’s Wall was hauled away and use was made of the beautifully dressed stone to construct the new buildings in the towns and villages nearby and some are still standing today.
Demolition work by its nature is an extremely dangerous business and demolishing any building is a complex and skilled process. Next time you see demolition work occurring on a building give a thought to the individuals who work in a dangerous situation daily and how much is involved in the meticulous planning, regulations compliance, care and skill that goes on to undertaking the project to clear the path for our future.