Introduction
The definition of the term ‘demolish’ is deliberate and controlled collapse of a structure. During the late 1970’s Fred Dibnah took over as the most well-known steeplejack in Great briBain when his work on demolishing large chimneys without the need for explosives was presented on Television. Fred was a fascinating individual and became well-known as an expert on restoring tall chimneys, so when it came to taking them down he knew just how to do it. He would cut an alcove at the foot of the chimney, then place wooden props to underpin the structure. By very carefully placing the props, the chimney would collapse in the correct direction when the wood was set alight and burned away. Once he was very nearly crushed because he miscalculated somewhat, showing how risky demolition work truly is.
The specific expression to demolish only came to exist in 1570, and was used from then on to mean the deliberate taking down or destroying of a building or structure. Even though in fact the job of demolition, in some mode or other, has been going on for millenia. Buildings have been demolished either by natural disturbances of the Planet’s crust or in the course of battles or assaults on towns for as long as there have been structures. The remaining wrecks would be taken away and rebuilt or used for other structures nearby and must be early types of recycling.
Preserving the Past – Preparing the Future.
To safeguard Britain’s history of farming the farm land between the established parts of the villages and towns is protected from expansion of urban sprawl. This acreage is called Green Belt and is preserved for farming that is essential to the continuing economic system of the nation. By conserving the Green Belt, urban areas are increasingly being squeezed to supply housing, so developers must be much more resourceful to uncover suitable sites.
Great Britain is a land with a very dense population per square mile. The amount of land available for development is limited when compared with other countries. Therefore there’s always a healthy need for space on which to build. Taking down old and abandoned properties and replacing them with brand-new is another way to counteract this shortage.
Land that may be disused industrial and commercial sites, but could possibly be contaminated with harmful waste or pollution, are classified as Brownfield sites. When 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 visitors and generate income.
Greyfield sites are distinct from Brownfield sites in that they do not possess the environmental issues of toxic waste material. The term greyfield originates from the large areas of asphalt that had once been car parks of industrial urban buildings. Their advantage is in the indisputable fact that the infrastructure such as highways, electricity, water, sewerage, and gas is already available. These urban areas that become under-utilised or abandoned and so are precious due to the fact they require hardly any remedial work to be developed. Cities such as Leeds and Manchester have had a massive programme of transforming the existing warehouses or factories into homes, retail establishments and bars, retaining the main shell and refurbishing the interior into valuable 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 physical size of the building.
What elements have re-use value?
What will the cleaned site’s re-use be 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 are often used to weaken the walls at the bottom, so that the building will topple; at the same time controlling the manner and direction of the fall. Safety issues are very important, and clean-up plans will also be considered when determining the way the structure will be demolished.
Traditional Demolition
In the old days the traditional way of demolishing a building was very primitive. After all the services were turned off, the men and equipment would go in and just knock down the walls. Then the whole building would collapse and the ensuing wreckage could be stacked onto lorries and be dumped in landfill sites. Concrete foundations were cracked by pneumatic drills and then the site would be cleaned of rubbish ready for the new work to start. Though nowadays demolition practitioners are at the mercy of rigorous planning, safety and monitoring polices and are heavily governed by the local council. The way in which a building is constructed will mean that one section relies on another for stability and sturdiness. For instance the roof of a property is not really fastened down apart from fixing tiles with nails to avoid them sliding. The rooftop stays in position using its own weight as the beams are laid on the top of the walls instead of being fixed into them like they used to be for much older buildings. The cross beams and purlins then link the whole thing together to tie down the frame of the roof. To this slats are laid as a frame for laying on the tiles or slates. Some other parts of a building are also 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 understand how to do the deconstruction.
Deconstruction and Recycling
The new approach to demolishing properties is called deconstruction – an environmentally friendly approach. Landfill sites are in short supply therefore the aim when demolishing a property is to minimise the quantity of waste material leftover.
Small structures like 2 or 3 storey buildings may be taken apart relatively easily. The project is often a painstaking task of dismantling manually – brick by brick – or beam by beam but by proceeding with care valuable elements are preserved for re-use. The value of deconstruction is that 90% or more of waste material is rescued from going into landfill sites and reclaimed components can be re-used and recycled for upcoming structures. The farmer opposite my new home sold his barns inside the farm yard for housing; when the builder demolished the barns he cleaned up the bricks and reused them to make the walls all around the farmhouse as a result retaining the character of the farm.
Newer techniques and equipment allows demolition companies to successfully segregate waste types on or off-site. Quality materials are recycled and re-used when practical in the new building making considerable reductions in project costs in addition to being good for the planet.
Concrete can now be rapidly cracked with a giant guillotine.
Rather than rubble belonging to the demolished property being taken to a landfill site for disposal it can be crushed on site to become 6f2 sub-base material or 6f2 crushed material, for the foundations of the new building, or it can be sold on and transported to other sites.
Copper pipes, lead, roof tiles or slates, floor tiles, wiring and doors, and solid wood panelling are useful items which might be preserved for recycling to be re-used. Many specialist suppliers offer reclaimed old or traditional building supplies in most towns and cities.
Tall Architectural Structures
Tower blocks and chimneys are the kind of tall structures which may need to be demolished. The demolition of tall buildings requires expert techniques. The tallest structure to be demolished lawfully was in 1967/8 of the Singer Building in New York. The fall of the World Trade Centre after the 9/11 attack in late 2001 demonstrates the horrendous devastation that occurs when the demolition is out of control and haphazard.
In the demolishing of high properties and big structures a wrecking ball on a crane may be used, but is rarely practiced since the swinging ball is rather uncontrollable. The proximity of other property is a deciding factor which stops the application of explosives to implode a tall building. So ‘High Reach’ demolition excavators are used where alternative methods are not suitable 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
Using explosives in demolition is extremely specialist work and getting it drastically wrong could well be devastating. If for example there is atmospheric pressure from low cloud above the implosion site, the shockwave may spread outwards instead of upwards causing the wave of energy and sound to break glass windows. If an implosion is not prepared correctly the danger may be destruction of surrounding buildings where flying debris could cause injuries to spectators.
For many people when they consider demolition they may have in mind the usage of explosives in the dramatic collapse of a tall building. This method is really called implosion using explosives. Implosion is vital for dense cities since 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 footprint.
Due to the dangers of working with explosives they are only used when other methods are too costly or impractical. Where there’s a partial collapse of a building and there are still primed explosives that did not go off, workers are in great danger because the remaining structure is extremely unstable. At the same time the demolition has to continue to secure the safety of the site.
Health and Safety
The work of demolition is an infinitely more technical and complicated process than a lot of people would appreciate. The work is highly hazardous and requires experienced and skilled operators to undertake the job. It is essential that personnel working in the market are thoroughly trained. Health and safety awareness is necessary in demolition services so it is advisable for operatives to have gained certificates of Competence in Demolition to ensure safety for both workers and public alike. All demolition jobs are regulated by Construction, Design and Management Regulations.
The sequence of demolition to follow are prerequisites of work a demolition company Nottingham 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 the 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 the supporting cards is removed.
There’s a strict sequence of events before any demolition will take place. Councils all over the country will have their own specific list for planning approval within their area, but a typical order would be the following:-
Provision of data
Information has to be provided about the construction of the structure to be demolished. Details of its previous use and also the appropriate demolition methods to be employed, including disposal of hazardous substances, need to be submitted by the demolition company.
Survey of Demolition
A comprehensive survey of the site to spot any structural problems, as well as risks associated with hazardous or flammable substances, will have to be discussed in detail with the authorities. (E.g. A disused garage where petrol was stored is a potential fire hazard so preventative measures will have to be taken).
Preferred and Safe Method of Work
A professional demolition company should be able to select the right way of disposal showing the outline dismantling process. Planning is essential for meticulous monitoring. The authorities will require an in depth statement of the safety procedures to used, and all parties involved must agree the methods 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 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 property 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 should be assessed and temporary services arranged, and individuals inconvenienced will need to be informed.
Conclusion
The goal in demolition is always to eliminate an unwanted house as safely and quickly as possible also in our modern environment attempts are made to recycle or re-use the majority 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 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 a very risky business and demolishing any building is a complex and skilled process. Next time you observe demolition work occurring on a building give a thought to the people 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 undertaking the project to clear the way for our future.
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