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The demolition trade has a certain reputation for being a harsh atmosphere in which brute force takes precedence over calculated thought; however this impression 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 grounded in the academic world.

One branch of this unnoticed work is site surveying, or more specifically pre-demolition and post-demolition topographical surveying. This kind of work demands a great balance of specific technical know-how as well as experience of the industry and a natural intuition for the complexities of the job. This article explores the ins and outs of this work.

Topographical Surveys

A topographical survey is a study of the physical features of a given piece of land. The aim of a topographical survey is to chart the naturally occurring and man-made features of a specific landscape to a high degree of precision. 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 broad range of landscapes, from open countryside to urban developments 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 multitude of tasks. A few of the more common uses are discussed below.

Common Applications for Topographical Surveys

Probably the most extensively used, and most commonly recognised application for topographical surveys is cartography, or map making. Modern maps include a great amount of detail about the landscape they relate to, including waterways, reliefs and ground surface, all of which will have been obtained via a topographical survey. This information is also being offered online.

Topographical surveys also have a major role to play in the construction business. When individuals or organisations are looking to build any kind of structure they will need to undertake extensive surveys as part of the design phase of the project.

Surveys definitely play a key safety role in primary industries like mining, or in other industries that interact with the land, such as demolition and infrastructure. Organisations in these fields will use surveys to prepare their projects, but also to be sure that they can guarantee the safety of their staff on site. As such, topographical surveys are often a legal requirement for these types of projects.

A site due for demolition work might undertake a demolition survey regarding worker protection and monetary planning motives.

Types of Survey

The world of topography covers a large number of physical characteristics so it is beneficial to identify what form of topographical survey is appropriate for a particular situation.

“Lie of the land” Surveys

These types of topographical surveys are designed to create a summary of the physical properties of any given plot of land. Whilst the information collected by the survey will be very accurate, and might be very extensive, the objective of these surveys is to give a site summary. They will usually be the first type of topographical survey that is undertaken on a job.

These surveys will usually include a boundary survey that sets out to define the extent of the site and spotlight any specific restraints that are determined by the geography of the site. They can also include a level survey that will measure 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 apparatus and even infrastructure characteristics. This type of study is more commonly associated with the demolition industry since it can give a detailed plan of the building to be demolished.

A building survey will probably include a measured survey, which entails creating a comprehensive plan of the external and interior proportions of a building. Depending on the requirements of the job, a measured survey could provide simple building “footprint” measurements, or might produce a very detailed plan of the structure. This information can be used to produce 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 necessary so the demolition firm can plan a demolition that is both adequate and secure. Often these surveys will also be legally requested.

Surveys will often contain information about the utility services that are present on a site prior to any demolition or construction work takes place. This is an essential safety aspect since any unmonitored damage to pipes and cables carrying water, gas and electricity could be very dangerous.

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 types of materials that can be located on site, for example, tiles and masonry, concrete that can be used as hardcore or even wood. By taking an accurate audit of site materials the construction company can more precisely determine the need to import building materials, or they can re-use the materials on a different job.

Although it is one necessary short-term expense, a pre demolition survey could produce economic gains in the long-term by identifying potential complications.

Importance of Site Surveys

Maybe the most significant reason to undertake a topographical site survey is to ensure the health and safety of the individuals who will be doing work on the site. The industries that most frequently call for site surveys are risky enough as it is without having to be concerned about the integrity of the ground on which they are working.

Another critical reason to get a proper survey done is to highlight any potential difficulties 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 discovered once digging or demolition has begun.

The inventory of site supplies, as previously mentioned, can be of great value to a demolition or construction company 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 reused on site provides 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 requirements.

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 certain vehicles or machinery then a new entry route or alternative equipment will have 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 phases of a construction 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 clearly a problem when it comes to the demolition stage of a project since the machinery is both expensive 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 workers to return to it, the surveying equipment can be restored to its initial 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 anyone who requires the topographical survey information. Most surveying firms will oversee this redeployment.

The need for strict measurement and planning is crucial in garage demolition projects given that houses and other structures may be nearby.

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 carefully by the right people. There are different divisions of site surveying and each one will have specific qualifications associated with it.

When selecting a company to undertake the surveying work required 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 performance on previous projects. It may also be worth considering how a company can deliver their survey data, i.e. in 3-D models or CAD ready formats, for ease of integration with other members of the project team.

Who will use the Survey Information?

Once an adequate level of information has been accumulated by a site survey it must be handed out to the appropriate personnel on-site. Who gets which pieces of information will mostly depend on the job roles being executed, but can also rely on the stage that a project is at. There will be much 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 concerning the physical relief of a site before the design phase, and a site materials record before they can plan the construction phase. The more data that can be made available to project planners will assist the smooth running of the venture.

Demolition Experts

Demolition businesses will want to know about the internal and external properties of any building or structures that they are set to take down. Whilst every job will have individual requirements, demolition experts will generally need to know about the fundamental structure 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 information about the natural lay of the land to determine what work will be required to create a stable footing for any building.