The demolition industry has a particular reputation for being a harsh environment in which brute force takes precedence over calculated thought; however this impression is far from correct. There is a substantial amount of work that happens behind the scenes of the demolition and construction sector which is firmly grounded in the academic arena.
One part of this unnoticed work is site surveying, or more specifically pre-demolition and post-demolition topographical surveying. This kind of work calls for a good balance of specific technical knowledge as well as experience of the industry and a genuine intuition for the complexities of the job.
Topographical Surveys
A topographical survey is a report of the physical features of a particular piece of land. The purpose of a topographical survey is to chart the naturally occurring and man-made features of a particular landscape to a high degree of precision. Whilst topography itself may refer to the surface of any object, it is more commonly associated with the surface of the Earth.
Topographical surveys can be carried out on a very wide range of environments, from open countryside to urban areas and across a variety of reliefs and land surfaces. Surveys can be designed to take into account a great many factors, such as ground variables or vegetation, and as such can be used for a number of tasks.
Common Applications for Topographical Surveys
Probably the most extensively used, and most commonly recognised application for topographical surveys is cartography, or map making. Modern day maps include a great amount of detail about the terrain they relate to, including waterways, elevations and ground surface, all of which will have been obtained via a topographical survey. This information is also being made available online.
Topographical surveys also have a major role to play in the construction business. When people or organisations are looking to build any kind of structure they will need to undertake extensive surveys as part of the design stage of the project. These surveys are often an indispensable part of any application for planning permission too.
Surveys definitely play a key safety role in primary industries such as mining, or in other industries that interact with the terrain, such as demolition and infrastructure. Companies in these fields will use surveys to prepare their projects, but also to be sure that they can ensure the safety of their workforce on site.
On projects where there are buildings to get demolished, building demolition surveys generally help planners during the demolition phase of the job.
Types of Survey
The world of topography addresses a large number of physical features so it is beneficial to determine what type of topographical survey is suitable for a particular situation. A few of the more typical types of survey necessary for construction sites are discussed below.
“Lie of the land” Surveys
These types of topographical surveys are fashioned to create an overview of the physical properties of any given plot of land. Whilst the data collected by the survey will be very accurate, and can be very extensive, the purpose of these surveys is to give a site summary.
These surveys will usually incorporate a boundary survey that sets out to define the extent of the site and highlight any particular restraints that are determined by the geography of the site. They may also include a level survey that will plot the elevation of the land and the various gradients that exist.
Building Surveys
Building surveys are more typically concerned with man-made constructions on a site, including the surveying of special equipment and even infrastructure characteristics. This type of study is more commonly associated with the demolition sector since it can give a detailed plan of the building to be demolished.
A building survey will almost certainly include a measured survey, which entails creating a detailed plan of the external and interior proportions of a structure. Depending on the requirements of the project, a measured survey might provide simple building “footprint” measurements, or might produce a very detailed plan of the structure. This information can be used to generate interior floor plans and even roof plans.
Content of a Topographical Site Survey
A survey of a demolition site will almost always include the information gathered by the types of boundary and building surveys described above. This information will be required so that the demolition company can plan a demolition that is both adequate and secure.
Surveys will often include information about the energy services that are present on a site before any demolition or construction work happens. This is an essential safety factor because any unmonitored damage to pipes and cables carrying water, gas and electricity could be very dangerous. The information can also be used to plan new structures, based upon the existing supply of these utilities.
Another aspect of the site survey will often be an inventory of materials on the site. This type of survey will be a quantity survey of the various sorts of materials that can be found on site, for example, tiles and masonry, concrete that can be used as hardcore or even timber. By taking an accurate audit of site materials the construction firm can more precisely gauge the need to import building materials, or they can re-use the materials on a different job.
Undertaking a thorough and complete house demolition survey would ensure the safety of residents in the immediate locality of the work site.
Importance of Site Surveys
Perhaps the most important reason to undertake a topographical site survey is to ensure the safety of the people who will be working on the site. The industrial sectors that most commonly call for site surveys are dangerous enough as it is without having to be concerned about the integrity of the ground on which they are working.
Another important reason to get a suitable survey done is to identify any potential problems that may arise because of the physical properties of the area. Particular things may not be evident on the surface of the site and will only be uncovered once digging or demolition has started. By then it may be too late to resolve these problems, or at best they will be costly issues to solve.
The inventory of site supplies, as previously mentioned, can be of great value to a demolition or construction enterprise working on a project. Not only are construction materials themselves expensive, but transporting them to the site may be a very expensive task in itself. Any time that material can be reused on site offers an opportunity to save development time and funds. Only by taking an exact audit of these materials can a company properly plan its imported material needs.
Topographical surveys can also identify other areas that will be of use to the project managers. For example, if the gradients on a site would be prohibitive to particular vehicles or equipment then a new entry route or alternative equipment will need to be found. Equally, an appropriate site will need to be found for the base of management operations for the project. Good site surveying can help out in these less tangible ways.
Positioning of Survey Control
During the surveying and construction stages of a building project, the equipment required for the physical surveying of the site and control of the survey information will often be stored on-site. This is obviously a problem when it comes to the demolition period of a project since the equipment is both costly and sensitive. It is therefore sensible to move this equipment off-site during demolition.
Once the demolition has taken place and the site has been deemed safe for staff to return to it, the surveying equipment can be restored to its original position on site. This will allow for efficient data collecting to take place for a post-demolition study, and maintains a single point of contact for anybody who needs the topographical survey information. Most surveying firms will oversee this redeployment.
One of the most specialised areas of industrial demolition concerns the disposal of dangerous substances that may be damaging to the environment.
Who can Perform Site Surveys?
Because topographical site surveys can play such a crucial role in the success or failure of a construction or demolition venture it is critical that they are carried out thoroughly by the right people. There are different divisions of site surveying and each one will have specific certificates associated with it. Getting surveyors with these specific skills will certainly be beneficial.
When selecting a company to undertake the surveying work necessary for your project it will be sensible to choose a company with a good reputation and a proven track record. Ask to see examples of their previous work and try to obtain feedback about their overall performance on past projects.
Who will use the Survey Information?
When an adequate level of details has been accumulated by a site survey it needs to be passed out to the appropriate people on-site. Who gets which pieces of information will largely depend on the job roles being executed, but can also rely on the stage that a project is at. There will be less need for materials information half way through construction for example.
Project Planners
Project planners will usually need access to all of the information gathered by a topographical survey, though they will particularly need to use information concerning the physical relief of a site before the design phase, and a site materials inventory before they can plan the construction phase. The more data that can be made available to project planners will aid the smooth running of the venture.
Demolition Experts
Demolition companies will want to know about the interior and exterior properties of any building or structures that they are arranged to take down. Whilst every project will have different requirements, demolition experts will generally need to know about the fundamental framework of a building and the materials it is made out of.
Site Engineers
Construction engineers on-site will be mainly interested in the survey data about the relief and topography of the site. It is usually the case that they will want to build on a flat surface, so they will use details about the natural lay of the land to calculate what work will be required to create a steady footing for any building.