The construction 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 appropriate. There is a huge amount of work that goes on behind the scenes of the demolition and construction sector that is firmly grounded in the academic arena.

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 good balance of specific technical understanding as well as experience of the industry and a genuine 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 actual features of a given plot of land. The aim of a topographical survey is to map the naturally occurring and man-made features of a specific landscape to a high degree of precision. Whilst topography itself may refer to the surface of virtually any object, it is more commonly associated with the surface of the Earth.

Topographical surveys could be carried out on a very broad range of landscapes, from open countryside to urban areas and across a variety of reliefs and land surfaces. Surveys can be developed to take into account a great number of factors, such as ground variables 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 widely used, and most generally recognised application for topographical surveys is cartography, or map making. Modern maps include a great deal 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.

Topographical surveys also have a key role to play in the construction industry. When people or companies 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 important part of any application for planning permission as well.

Surveys definitely play a key safety role in primary industries such as mining, or in other industrial sectors that interact with the terrain, such as demolition and infrastructure. Companies in these fields will use surveys to plan their projects, but also to make sure that they can ensure the safety of their workforce on site. As such, topographical surveys are often a legal prerequisite for these types of projects.

On projects where there are structures to get demolished, building demolition surveys generally help planners during the demolition stage of the job.

Types of Survey

The arena of topography addresses a large number of physical features so it is beneficial to determine what type of topographical survey is appropriate for a particular scenario. A few of the more common types of survey necessary for construction sites are discussed below.

“Lie of the land” Surveys

These types of topographical surveys are designed to create a summary of the physical characteristics of any given plot of land. Although the data gathered by the survey will be extremely accurate, and may be very extensive, the purpose of these surveys is to give a site summary.

These surveys will generally incorporate a boundary survey that sets out to determine 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. A survey can be customised to specification though.

Building Surveys

Building surveys are more generally concerned with man-made structures on a site, including the surveying of special equipment and even infrastructure features. This type of study is more regularly associated with the demolition sector 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 exterior and interior dimensions of a building. Depending on the requirements of the project, 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 definitely include the details gathered by the types of boundary and building surveys described above. This information will be necessary so that the demolition firm can plan a demolition that is both satisfactory and secure. Often these surveys will also be legally required.

Surveys will often contain information about the utility services that are present on a site before any demolition or construction work takes place. This is an essential safety factor since any unmonitored destruction 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 resources 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 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. These surveys can be made pre-demolition as well as post-demolition.

Although it is one needed short-term expense, a pre demolition survey can produce economic rewards in the long-term by highlighting potential issues.

Importance of Site Surveys

Maybe the most significant reason to undertake a topographical site survey is to ensure the health and safety of the people who will be doing work on the site. The industrial sectors that most frequently 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 critical reason to get a proper survey done is to highlight 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 begun.

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 may be a very expensive task in itself. Any time that material can be reused on site provides an opportunity to save development time and money. Only by taking an accurate audit of these materials can a company correctly 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 specific vehicles or equipment then a new entry route or alternative equipment will have to be found. Equally, a suitable 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 kept on-site. This is clearly a problem when it comes to the demolition phase of a project since the equipment is both costly and sensitive.

Once the demolition has taken place 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 survey, and maintains a single point of contact for anyone who requires the topographical survey information. Most surveying companies will oversee this redeployment.

It is important to carry out surveys prior to and also following the demolition of buildings because disruption to utility services must be supervised closely.

Who can Perform Site Surveys?

Because topographical site surveys can play such a vital role in the success or failure of a building or demolition project it is critical that they are carried out thoroughly by the right people. There are different branches of site surveying and each one will have specific certificates associated with it.

When choosing a company to undertake the surveying work required for your project it will be wise to choose a business with a good reputation and a proven track record. Ask to see examples of their previous work and try to get feedback about their overall performance on past projects.

Who will use the Survey Information?

Once an adequate level of details 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 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 require 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 prepare the construction phase.

Demolition Experts

Demolition companies will want to know about the interior and exterior properties of any building or structures that they are set to take down. Whilst every project will have individual requirements, demolition workers 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 site. It is normally the case that they will need to assemble on a flat surface, so they will use information about the natural lay of the land to calculate what work will be required to create a stable foundation for any building.