Introduction
The meaning of the phrase ‘demolish’ is deliberate and controlled collapse of a structure. During the late 1970’s Fred Dibnah took over as the most famous steeplejack in Britain when his work on demolishing large chimneys without having the requirement of explosives was displayed on Tv. Fred was an appealing figure and became well-known as an expert on restoring tall chimneys, so when it came to knocking them down he knew exactly how to acheive it. He would cut an niche at the base of the chimney, and place wooden props to hold the structure. By means of properly 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 very nearly crushed because he miscalculated slightly, demonstrating how dangerous demolition work really is.
The particular phrase to demolish only came into being in 1570, and was adopted after that to mean the deliberate taking down or destroying of a building or structure. Even though in reality the process of demolition, in some mode or other, has been taking place for millenia. Buildings have been wrecked either by natural disruptions of the Earth’s crust or during battles or attacks on towns for as long as there have been structures. The leftover ruins were removed and rebuilt or used for other structures close by and must be early examples of recycling.
Preserving the Past – Preparing the Future.
To safeguard Britain’s history of agriculture the acreage between the established regions of the villages and towns is protected from growth of urban sprawl. This land is called Green Belt and it is preserved for farming which is essential to the continuing economy of the nation. By safeguarding the Green Belt, urban areas are increasingly being squeezed to provide housing, so developers need to be a lot more resourceful to uncover suitable sites.
Britain is a country with an incredibly dense population per square mile. The amount of land readily available for development is small compared to other nations. Therefore there’s always a healthy demand for space on which to build. Taking down old and unused buildings and replacing them with new is an excellent method to combat this general shortage.
Land that may be disused industrial and commercial sites, but could be contaminated with dangerous waste or pollution, are known as Brownfield sites. As soon as the land has been cleaned up they can be potentially valuable for redevelopment. Both Glasgow and South Wales created gardens out of old industrial sites and put in Shopping centres to draw in holidaymakers and visitors and generate income.
Greyfield sites are different to Brownfield sites because they do not possess the environmental problems of harmful waste material. The term greyfield comes from the large areas of asphalt that had once been car parks of commercial urban properties. Their worth is incorporated in the fact that the facilities like roads, electricity, water, sewerage, and gas is already in position. These kinds of urban areas that become under-utilised or abandoned and therefore are valuable simply because they require little or no remedial work to be developed. Cities like Leeds and Manchester have had an enormous programme of converting the old warehouses or factories into homes, shops and cafes, retaining the original shell and refurbishing 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 construction type and actual physical dimensions of the structure.
What products have re-use value?
What will the cleaned site’s re-use be for?
Where are the waste by-products going to be disposed?
What considerations need to be made with regards electricity, water, sewerage and gas mains.
Hydraulic excavators and bulldozers may be used to undermine the walls at the foundation, so that the structure will topple; at the same time managing the manner and course of the fall. Questions of safety are paramount, and clean-up tactics will also be taken into account when determining the way the property will be demolished.
Old fashioned Demolition
At one time the standard way of demolishing a structure was very crude. After the services were disconnected, the men and equipment would go ahead and simply just knock down the walls. Then the entire framework would fall and the resulting rubble could be stacked on lorries and be dumped in landfill sites. Concrete footings were broken up by pneumatic tools and the site could be cleared of rubbish ready for the new work to begin. However nowadays demolition practitioners are at the mercy of strict planning, health and safety and inspection laws and are heavily controlled by the local council. The way in which a building is constructed means that one part relies on another for stability and strength. For instance the roof of a building isn’t fastened down save for fixing tiles with nails to stop them dropping. The roof stays in position with its own weight as the beams are laid on top of the walls instead of being fixed into them as they once were for much older houses. The cross beams and purlins then connect the whole thing together to secure the frame of the roofing. To this slats are laid to provide a frame for laying on the tiles or slates. Some other areas of a building are interdependent so when it comes to demolition these factors are taken into consideration in the sequence of deconstruction. In this way, like Fred Dibnah you need to be an expert in construction to know how to perform the deconstruction.
Deconstruction and Recycling
The modern approach to demolishing structures is known as deconstruction – an environmentally friendly approach. Landfill sites are in short supply and so the aim when demolishing a building is to reduce the quantity of waste material remaining.
Smaller constructions such as 2 or 3 storey homes can be disassembled quite simply. The work may be a slow task of dismantling manually – brick by brick – or beam by beam but by going very carefully expensive elements are safeguarded for re-use. The beauty of deconstruction is that 90% or maybe more of waste materials is rescued from going directly into landfill sites and reclaimed components can be re-used and recycled for upcoming buildings. The farmer opposite my bungalow sold his barns within the farm yard for construction; when the contractor demolished the barns he cleaned up the bricks and reused them to make the wall around the farmhouse hence keeping the character of the place.
Modern day techniques and equipment enables demolition firms to efficiently segregate waste material types on or off-site. Quality products are recycled and re-used whenever practical in the new construction creating considerable reductions in project costs as well as being good for the planet.
Concrete can now be easily cracked using a giant guillotine.
Demand increases daily for 6f2 recycled material because it is an excellent aggregate for foundations of road and new buildings. as it provides a viable alternative to disposing of the demolished building remnants to landfill.
Copper pipes, lead, roof tiles or slates, floor tiles, wiring and doors, and wooden panelling are useful objects which are conserved for recycling to be re-used. Countless specialist companies offer up reclaimed old or classic building products in a lot of towns and cities.
Taller Structures
Tower blocks and chimneys are the kind of tall structures that might need to be demolished. The demolition of tall structures necessitates specialist techniques. The tallest structure to be demolished lawfully was in 1967/8 of the Singer Building in New York. The collapse of the World Trade Centre after the 9/11 assault in 2001 illustrates the horrendous devastation that develops when 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 utilised, but is rarely practiced because the swinging ball is relatively uncontrollable. The proximity of other buildings is often a determining issue which often prevents the employment of explosives to implode a tall structure. So ‘High Reach’ demolition excavators are used wherever alternative approaches will not be possible to demolish the highest part 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 very specialist work and getting it drastically wrong would be devastating. If for example there is atmospheric pressure from low cloud above the implosion site, the shockwave may spread outwards instead of upwards resulting in the wave of energy and sound to break windows. If the implosion is not prepared correctly the risk may be damage to surrounding properties where flying debris might cause injuries to spectators.
For many individuals when they think of demolition they may have in mind the use of explosives in the dramatic collapse of a tall building. This method is really called implosion using explosives. Implosion is vital for dense cities because it brings down a tall building so the surrounding environment is damaged as little as possible. The collapse takes only seconds for the building to crash into its own footprint.
Because of the dangers of working with explosives they are only used when other methods are too costly or impractical. Where there is a partial collapse of the building and there are still primed explosives that did not go off, workers are in great danger because the remaining structure is very unstable. On the other hand the demolition has to carry on and secure the safety of the site.
Health and Safety
The task of demolition is an infinitely more technical and complicated process than most people would appreciate. The job is highly dangerous and requires experienced and skilled operators to undertake the work. It is crucial that personnel working in the industry are adequately trained. Health and safety awareness is important in demolition services so it is best 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 the Construction, Design and Management Regulations.
Your local Nottingham demolition company has the necessary skills to ensure that they complete the procedure above in order to gain demolition planning approval.
Sequence of Demolition
An incorrect sequence of dismantling can lead to unplanned collapse of a building since the stability of any structure is reliant on the interdependence of the component parts. Think of a house of cards and what happens 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 have their particular specific list for planning approval within their area, but a typical order could be as follows:-
Provision of data
Information should be provided about the construction of the structure to be demolished. Details of its previous use and also the appropriate demolition methods to be used, including disposal of hazardous substances, need to be submitted by the demolition company.
Survey of Demolition
A thorough survey of the site to recognize any structural problems, in addition to risks regarding hazardous or flammable substances, should be discussed in detail with the authorities. (E.g. A disused garage where petrol was 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 appropriate method of disposal showing the outline dismantling process. Planning is essential for vigilant monitoring. The authorities will require an in depth statement of the safety procedures to used, and all parties involved have to agree the techniques before any demolition can take place.
Preparation and Planning
Issues like asbestos abatement, rodent baiting, dealing with hazardous substances, disconnecting utilities, and making safe any electric, gas or other services must be shown in the planning stage. There is a lot 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 you can find heavily populated areas around the demolition site the protection of the public is paramount. Any health risks will have to be assessed and temporary services arranged, and people affected will need to be informed.
Conclusion
The goal in demolition is to eliminate an unwanted structure as safely and quickly as possible also in our modern environment efforts are made to recycle or re-use a lot of the old material. This is not a brand new idea even though the word itself is relatively modern. On the borders between England and Scotland after the Romans left, a substantial 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 several remain standing today.
Demolition work by its nature is a very 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 people who work in a dangerous situation daily and just how much is associated with the meticulous planning, regulations compliance, care and skill that goes on to carrying out the project to clear the path for our future.