The demolition trade has a particular reputation for being a harsh environment in which brute force takes precedence over calculated thought; however this image is far from appropriate. There is a substantial amount of work that happens behind the scenes of the demolition and construction industry that is firmly rooted in the academic arena. Furthermore, this unseen work is critical to the success of the more visible procedures.
One part of this unnoticed work is site surveying, or more precisely pre-demolition and post-demolition topographical surveying. This type of work calls for a great balance of specific technical knowledge as well as experience of the industry and a natural intuition for the intricacies of the job. This article explores the ins and outs of this work.
Topographical Surveys
A topographical survey is a report of the physical features of a given piece of land. The purpose of a topographical survey is to map the naturally occurring and man-made features of a particular landscape to a high degree of accuracy. Whilst topography itself can 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 developments and across a variety of elevations and land surfaces. Surveys can be designed to take into account a great number of factors, such as ground variables or vegetation, and as such can be used for a multitude of tasks. A few of the more common uses are discussed below.
Common Applications for Topographical Surveys
Perhaps the most widely used, and most generally 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 gathered via a topographical survey.
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 perform extensive surveys as part of the design phase of the project. These surveys are often an essential part of any application for planning permission too.
Surveys also play a key safety role in primary industries like mining, or in other industries that interact with the land, such as demolition and infrastructure. Companies in these fields will use surveys to plan their projects, but also to be sure that they can guarantee the safety of their workforce on site. As such, topographical surveys are often a legal requirement for these types of projects.
The newly appreciated health dangers of asbestos help make asbestos demolition surveys crucial to jobs where older structures are being destroyed.
Types of Survey
The world of topography addresses a large number of physical characteristics so it is beneficial to determine what form of topographical survey is appropriate for a particular scenario.
“Lie of the land” Surveys
These types of topographical surveys are designed to create an overview of the physical properties of any given plot of land. Although the information collected by the survey will be extremely accurate, and may be very extensive, the objective of these surveys is to provide a site summary.
These surveys will generally include a boundary survey that sets out to determine the extent of the site and spotlight any particular restraints that are determined by the geography of the site. They can also include a level survey that will plot the elevation of the land and the numerous gradients that exist. Any survey can be customised to specification though.
Building Surveys
Building surveys are more typically concerned with man-made structures on a site, including the surveying of special equipment and even infrastructure features. This type of survey is more commonly associated with the demolition sector since it can give a detailed plan of the structure to be demolished. It can be used for other projects as well.
A building survey will almost certainly include a measured survey, which involves creating a detailed plan of the external and internal dimensions of a building. Depending on the requirements of the job, a measured survey could provide simple building “footprint” measurements, or might produce a highly detailed plan of the structure.
Content of a Topographical Site Survey
A survey of a demolition site will almost always include the details gathered by the types of boundary and building surveys described above. This information will be needed so the demolition firm can plan a demolition that is both satisfactory and safe. Often these surveys will also be legally required.
Surveys will often contain information about the energy services that are present on a site prior to any demolition or construction work takes place. This is an important safety aspect because any unmonitored damage to pipes and cables carrying water, gas and electricity might be very dangerous.
Another aspect of the site survey will often be an inventory of resources on the site. This type of survey will be a quantity survey of the various types of materials that can be located 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 company can more accurately determine the need to import building resources, or they can re-use the materials on a different project. These surveys could be made pre-demolition as well as post-demolition.
Modern construction and demolition businesses supply information on their own company website where clients can view case studies or references for past projects.
Importance of Site Surveys
Perhaps the most significant reason to perform a topographical site survey is to ensure the safety of the individuals who will be doing work on the site. The industries that most commonly call for site surveys are dangerous enough as it is without having to worry about the condition 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 characteristics of the region. Certain things will not be evident on the surface of the site and will only be discovered once digging or demolition has started. By then it may be too late to fix these problems, or at best they will be expensive issues to solve.
The inventory of site supplies, as previously stated, can be of great benefit to a demolition or construction company working on a project. Not only are construction materials themselves costly, but importing them to the site could be a very expensive task in itself. Any time that material can be recycled on site offers an opportunity to save development time and money.
Topographical surveys can also identify other areas that will be of use to the project planners. For example, if the gradients on a site would be prohibitive to particular vehicles or machinery then a new access route or alternative equipment will need to be found.
Positioning of Survey Control
During the surveying and construction stages of a construction project, the apparatus required for the physical surveying of the site and control of the survey information will often be stored on-site. This is clearly a problem when it comes to the demolition period of a project since the machinery 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 gathering to take place for a post-demolition survey, and retains a single point of contact for anybody who needs the topographical survey information.
Experience is often a deciding variable when selecting a buildings demolition service provider because every job has unique requirements and unique challenges.
Who can Perform Site Surveys?
Because topographical site surveys can play such a vital role in the success or failure of a construction or demolition venture it is critical that they are undertaken 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 advantageous.
When choosing a company to undertake the surveying work necessary for your project it will be wise to choose a company with a good reputation and a proven track record. Ask to see reviews of their previous work and try to get feedback about their overall performance on previous projects.
Who will use the Survey Information?
Once an adequate level of information has been accumulated by a site survey it must be passed out to the appropriate personnel on-site. Who gets which pieces of information will mostly depend on the job roles being performed, but can also rely on the stage that a project is at. There will be less need for materials information midway through construction for example.
Project Planners
Project planners will generally require access to all of the information gathered by a topographical survey, although they will particularly need to use information about the physical relief of a site before the design phase, and a site materials record before they can prepare the construction phase. The more data that can be made available to project planners will aid the smooth running of the project.
Demolition Experts
Demolition businesses will want to know about the interior and exterior properties of any building or structures that they are arranged to take down. Whilst every job 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 information about the relief and topography of the terrain. It is usually the case that they will need to build on a flat surface, so they will use details about the natural lay of the land to determine what work will be required to create a steady footing for any building.
