The Different Stages of Demolition
Introduction
The definition of the phrase ‘demolish’ is deliberate and controlled collapse of a structure. During the late 70′s Fred Dibnah took over as the most celebrated steeplejack in Britain when his work on demolishing tall chimneys without the requirement of explosives was displayed on Television. Fred was an intriguing individual 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 have to chop an niche at the bottom of the chimney, and place wooden props to underpin the structure. As a result of properly positioning the props, the chimney would be likely to collapse in the correct place once the wood was set alight and burned away. Once he was very nearly killed because he miscalculated somewhat, showing just how risky demolition work truly is.
The specific term to demolish only came to exist in 1570, and was adopted there after to mean the deliberate taking down or destroying of a building or structure. Although in reality the task of demolition, in some mode or other, has been occurring for thousands of years. Structures have been wrecked either by natural disruptions of the Planet’s crust or in the course of battles or attacks on towns for as long as there have been buildings. The remaining ruins were removed and rebuilt or used for other structures in the area and must be early examples of recycling.
Preserving the Past – Preparing the Future.
To protect The UK’s history of farming the land between the established regions of the villages and towns is shielded from expansion of urban sprawl. This land is known as Green Belt and it’s preserved for farming that is fundamental to the continuing economic system of the nation. By protecting the Green Belt, urban areas are being squeezed to provide housing, so developers need to be much more imaginative to locate suitable sites.
Britain is a land with an incredibly dense population per square mile. The amount of land readily available for construction is restricted in comparison to other nations. Consequently there’s always a healthy demand for space on which to build. Taking down old and abandoned structures and replacing them with brand-new is an excellent method to counteract this shortage.
Land that is disused industrial and commercial sites, but could be contaminated with dangerous waste or pollution, are called Brownfield sites. Once the land has been cleaned up they may be potentially valuable for redevelopment. Both Glasgow and South Wales developed gardens from disused commercial sites and put in Shopping centres to draw in tourists and generate income.
Greyfield sites are completely different to Brownfield sites because they do not have the environmental problems of dangerous waste material. The term greyfield comes from the large areas of asphalt that had once been car parks of commercial urban properties. Their advantage is in the fact that the commercial infrastructure which includes highways, electricity, water, sewerage, and gas is already in position. These types of urban areas that come to be under-utilised or abandoned and therefore are precious mainly because they require a small amount of remedial work to be exploited. Cities such as Leeds and Manchester have experienced a massive programme of transforming the old warehouses or factories into homes, retail establishments and restaurants, keeping the original shell and refurbishing the interior into modern accommodation.
The Demolition Process
A skilled Birmingham demolition company contracted to do the work will have taken the time to perform an initial basic review of the following.
The construction type and actual dimensions of the structure.
What products have re-use value?
What will the cleaned site’s re-use be intended for?
Where are the waste material by-products likely to be disposed?
What considerations need to be made with regards electricity, water, sewerage and gas mains.
Hydraulic excavators and bulldozers can be used to weaken the walls at the roots, so that the structure will topple; at the same time controlling the manner and direction of the fall. Issues of safety are very important, and clean-up systems are also taken into consideration when determining how the structure is to be demolished.
Old fashioned Demolition
In the old days the traditional means of demolishing a property was quite primitive. Once all the services were turned off, the men and machinery would go ahead and just knock down the walls. Then the whole framework would collapse and the ensuing rubble could be piled onto trucks and be dumped in land fill sites. Concrete foundations would be split up by pneumatic drills and then the site would be cleared of waste ready for the new work to commence. However these days demolition businesses are subject to stringent planning, safety and monitoring polices and are also heavily governed by the local council. The way in which a building is constructed will mean that one segment is dependent on another for solidity and strength. For example the roof of a house isn’t fastened down other than fixing roof tiles with nails to avoid them dropping. The rooftop stays in position using its own weight because the beams are laid on top of the walls instead of being attached into them like they once were for much older houses. The cross beams and purlins then connect the whole thing together to tie down the frame of the roof. To this slats are laid to provide a frame for laying on the tiles or slates. Some other parts of a building may also be 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 a professional in construction to understand how to do the deconstruction.
Deconstruction and Recycling
The modern system of demolishing structures is known as deconstruction – a green approach. Landfill sites are in short supply and so the aim when demolishing a building is to reduce the quantity of waste materials remaining.
Small structures like two or three storey houses can be disassembled quite easily. The work is often a slow task of dismantling by hand – brick by brick – or beam by beam but by going carefully costly components are preserved for re-use. The beauty of deconstruction is that 90% or even more of waste materials is prevented from going directly into landfill sites and reclaimed resources can be re-used and recycled for upcoming buildings. The farmer opposite my family home sold his barns in the farm yard for construction; when the builder demolished the barns he cleaned up the bricks and reused them to make the wall around the farmhouse thus keeping the character of the farm.
Modern day solutions and machinery permits demolition firms to efficiently segregate waste material groups on or off-site. Building items are recycled and re-used whenever possible within the new construction creating significant savings in project costs not to mention being good for the environment.
Concrete can now be rapidly cracked with a giant guillotine.
Through the use of the new Nottingham crushing plant machinery the demolished building bricks and stone can be recycled into 6f2 recycled materials for use on new buildings.Crushed material from the demolition can be used as a sub-base for the new building foundations or used on other sites where construction is underway.
Copper pipes, lead, roof tiles or slates, floor tiles, wiring and doors, and wood panelling are valued objects which are conserved for recycling to be re-used. Many specialist companies offer reclaimed old or traditional building items in the majority of towns and cities.
Taller Architectural Structures
Tower blocks and chimneys are the kind of tall architectural structures that might need to be demolished. The demolition of tall structures necessitates expert tactics. The tallest structure 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 attack in late 2001 shows the terrible devastation that occurs when the demolition is unchecked and haphazard.
In the demolishing of tall buildings and sizeable structures a wrecking ball on a crane can be used, but is hardly ever practiced since the swinging ball is rather uncontrollable. The proximity of other structures is a determining issue which often inhibits the use of explosives to implode a tall building. So ‘High Reach’ demolition excavators are widely-used wherever other methods are not possible to demolish the highest 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
The use of explosives in demolition is incredibly specialist work and getting it wrong could well be catastrophic. If for instance there is atmospheric pressure from low cloud above the implosion site, the shockwave may spread outwards rather than upwards resulting in the wave of energy and sound to break glass windows. If the implosion is not prepared correctly the danger might be destruction of surrounding buildings where flying debris might cause harm to spectators.
For many people when they think of demolition they may have in mind the usage of explosives in the spectacular collapse of a tall building. This method is really called implosion using explosives. Implosion is essential for dense towns as it brings down a tall building so that the surrounding environment is damaged as little as possible. The collapse takes only a few moments for the building to fall into its footprint.
Due to the risks of working with explosives they will only be 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 failed to go off, workers are in great danger since the remaining structure is extremely unstable. Concurrently the demolition has to continue to secure the safety of the site.
Health and Safety
The task of demolition is an infinitely more technical and complicated process than a lot of people would appreciate. The work is extremely hazardous and requires experienced and skilled operators to carry out the task. It is crucial that personnel working in the market are adequately trained. Health and safety awareness is necessary in demolition services so it is preferable for operatives to have gained certificates of Competence in Demolition to ensure safety for both workers and public alike. All demolition work is regulated by 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 accidental collapse of a building since the stability of any structure is reliant on the interdependence of its 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 own specific list for planning approval in their area, but a typical order could be the following:-
Provision of data
Information should 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 applied, including disposal of hazardous substances, have to be submitted by the demolition company.
Survey of Demolition
A comprehensive survey of the site to recognize any structural problems, in addition to risks associated with hazardous or flammable substances, will need to be discussed at length with the authorities. (E.g. A disused garage where petrol was stored is often a potential fire hazard so preventative measures will surely have to be taken).
Preferred and Safe Method of Work
A good demolition company will be able to select the correct procedure for disposal showing the outline dismantling process. Planning is essential for assiduous monitoring. The authorities will require an in depth 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 like asbestos abatement, rodent baiting, dealing with hazardous substances, disconnecting utilities, and making safe any electric, gas or other services need to be shown in the planning stage. There is a great deal of preparation to be done before even starting work on demolishing the structure itself.
Protection of the Public
Safety cannot be compromised so wherever you can find heavily populated areas surrounding the demolition site the protection of the public is paramount. Any health risks will have to be assessed and temporary services arranged, and individuals inconvenienced will have to be informed.
Conclusion
The goal in demolition is always to eliminate an unwanted house as safely and quickly as possible and in our modern environment attempts are made to recycle or re-use the majority of the old material. This may not be a new idea although 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 remain standing today.
Demolition work by its nature is a very dangerous business and demolishing any building is a complex and skilled process. The next time you see demolition work occurring on a building give a thought to the individuals who work in a dangerous situation daily and just how much is involved in the meticulous planning, regulations compliance, care and skill that goes on to carrying out the project to clear the way for our future.
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