The demolition industry has a particular character for being a tough environment in which brute force takes precedence over calculated thinking; however this image is far from correct. There is a huge amount of work that happens behind the scenes of the demolition and construction industry that is firmly rooted in the academic arena. Moreover, 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 sort of work calls for a great balance of specific technical knowledge as well as experience of the industry and a natural intuition for the complexities of the job.
Topographical Surveys
A topographical survey is a report of the actual features of a given piece of land. The aim of a topographical survey is to map the naturally occurring and man-made traits 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 planet.
Topographical surveys could be carried out on a very broad 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 conditions or vegetation, and as such can be used for a number of tasks. A few of the more common uses are discussed below.
Common Applications for Topographical Surveys
Probably the most extensively 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 landscape 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 key role to play in the construction business. When people or companies are looking to construct any kind of structure they will need to perform extensive surveys as part of the design stage of the project. These surveys are often an essential part of any application for planning permission as well.
Surveys also play a key safety part in primary industries such as 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 ensure that they can guarantee the safety of their staff on site.
Most construction and demolition companies within the UK carry out demolition surveys for jobs they are working on.
Types of Survey
The arena of topography covers a large number of physical features so it is important to determine what type of topographical survey is suitable for a particular scenario.
“Lie of the land” Surveys
These types of topographical surveys are fashioned to create a summary of the physical characteristics of any given plot of land. Although the information collected by the survey will be very accurate, and may be very extensive, the purpose of these surveys is to give a site summary. They will usually be the first type of topographical survey that is carried out on a project.
These surveys will generally incorporate a boundary survey that sets out to determine the extent of the site and highlight any specific restraints that are determined by the geography of the site. They can also include a level survey that will plot the elevation of the terrain and the various gradients that exist.
Building Surveys
Building surveys are more typically concerned with man-made structures on a site, including the surveying of special apparatus and even infrastructure characteristics. This type of survey is more regularly associated with the demolition sector because it can give a detailed plan of the structure to be demolished.
A building survey will almost certainly include a measured survey, which involves creating a detailed plan of the external and internal proportions of a structure. Depending on the requirements of the job, a measured survey could provide simple building “footprint” dimensions, or might produce a highly detailed plan of the structure.
Content of a Topographical Site Survey
A survey of a demolition site will almost definitely include the details gathered by the types of boundary and building surveys described above. This information will be needed so that the demolition firm 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 aspect since any unmonitored damage to pipes and cables carrying water, gas and electricity might be very dangerous. The information might also be used to plan new buildings, based upon the existing supply of these ammenities.
Another aspect of the site study will often be an audit of materials on the site. This type of survey will be a quantity survey of the various kinds of materials that can be found on site, for example, tiles and masonry, concrete that can be utilised as hardcore or even timber. By getting an accurate audit of site materials the construction company can more accurately gauge the need to import building resources, or they can re-use the materials on a different job. These surveys could be made pre-demolition and post-demolition.
Nearly all building sites need topographical demolition surveys now legislation and safety have become critical requirements.
Importance of Site Surveys
Perhaps the most important reason to undertake a topographical site survey is to ensure the health and safety of the individuals who will be working on the site. The industrial sectors that most frequently call for site surveys are risky enough as it is without having to worry about the integrity of the ground on which they are working. Taking a detailed topographical survey can help to mitigate safety risks of this nature.
Another critical reason to get a proper survey done is to identify any potential problems that may arise because of the physical characteristics of the area. Particular things will not be evident on the surface of the site and will only be discovered once digging or demolition has begun. By then it may be too late to deal with 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 enterprise working on a project. Not only are building materials themselves expensive, but transporting 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 funds. Only by taking an exact audit of these supplies can a company properly plan its imported material requirements.
Topographical surveys can also highlight other areas that will be of use to the project managers. For example, if the gradients on a site would be prohibitive to certain vehicles or equipment then a new access route or alternative machinery will need to be found. Equally, an appropriate site will need to be found for the base of control operations for the project. Good site surveying can help out in these less tangible ways.
Positioning of Survey Control
During the surveying and construction phases of a building project, the equipment required for the physical surveying of the site and control of the survey data will often be kept 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 occurred and the site has been deemed safe for personnel 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 requires the topographical survey information. Most surveying companies will oversee this redeployment.
To truly rid any worksite of a building demolish the external framework as well as the footings it was built on.
Who can Perform Site Surveys?
Because topographical site surveys can play such a critical role in the success or failure of a construction or demolition project it is vital 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. Finding surveyors with these specific qualifications will certainly be advantageous.
When selecting a company to undertake the surveying work required for your project it will be sensible 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 performance on previous projects.
Who will use the Survey Information?
When an adequate level of information has been gathered by a site survey it needs to be handed out to the appropriate people on-site. Who gets which pieces of information will largely 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 half way through construction for example.
Project Planners
Project planners will generally 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 record before they can plan the construction phase.
Demolition Experts
Demolition organisations will want to know about the internal and external characteristics of any building or structures that they are set to take down. Whilst every job will have individual requirements, demolition workers will typically 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 particularly 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.