Pre-Demolition Site Surveys

The construction industry has a certain reputation for being a tough atmosphere in which brute force takes precedence over calculated thought; however this impression is far from appropriate. 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 world.

One branch of this unnoticed work is site surveying, or more specifically pre-demolition and post-demolition topographical surveying. This kind 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 plot of land. The aim of a topographical survey is to map the naturally occurring and man-made features of a particular landscape to a high degree of precision.

Topographical surveys can 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 developed to take into account a great number of factors, such as ground conditions or vegetation, and as such can be used for a multitude of tasks. A few of the more common uses are outlined below.

Common Applications for Topographical Surveys

Perhaps 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 landscape they relate to, including waterways, reliefs 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 industry. When individuals 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.

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. Companies in these industries will use surveys to prepare their projects, but also to ensure that they can ensure the safety of their workforce on site. As a result, topographical surveys are often a legal prerequisite for these types of projects.

On sites where there are buildings to be removed, building demolition surveys will help planners throughout the demolition phase of the project.

Types of Survey

The arena of topography covers a large number of physical characteristics so it is important to determine what type of topographical survey is suitable for a particular situation. A few of the more typical types of survey required for construction sites are discussed below.

“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. Whilst the information gathered by the survey will be extremely accurate, and may be very extensive, the purpose of these surveys is to provide a site summary.

These surveys will usually incorporate 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 measure the elevation of the terrain 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 constructions on a site, including the surveying of special machines and even infrastructure features. 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. It may be used on other projects as well.

A building survey will probably include a measured survey, which entails creating a precise plan of the exterior and internal proportions of a structure. Depending on the requirements of the job, a measured survey might provide simple building “footprint” dimensions, 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 mentioned above. This information will be needed so the demolition company can plan a demolition that is both adequate and secure. More often than not these surveys will also be legally requested.

Surveys will often include information about the utility services that are present on a site before any demolition or construction work happens. This is an important safety aspect because any unmonitored damage to pipes and cables carrying water, gas and electricity could be very dangerous.

Another aspect of the site study will often be an audit of materials on the site. This type of study will be a quantity survey of the various kinds 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 firm can more accurately determine the need to import building materials, or they can re-use the materials on a different job.

Contemporary construction and demolition businesses provide details within their corporate website so clients can see case studies or references regarding past projects.

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 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. Taking a detailed topographical survey can help to eliminate safety risks of this nature.

Another critical reason to get a proper survey done is to identify 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 started.

The inventory of site supplies, as previously stated, can be of great benefit to a demolition or construction organisation 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 money. Only by taking an exact 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 certain vehicles or equipment then a new entry route or alternative equipment will need to be found.

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 information will often be stored on-site. This is obviously a problem when it comes to the demolition stage of a project since the machinery is both costly and sensitive.

Once the demolition has taken place and the site has been deemed safe for personnel to return to it, the surveying equipment can be restored to its initial position on site. This will allow for efficient data gathering to take place for a post-demolition study, and keeps a single point of contact for anyone who needs the topographical survey information. Most surveying firms will oversee this redeployment.

To truly rid any worksite of any building demolish the external structure as well as the foundations it was built upon.

Who can Perform Site Surveys?

Since topographical site surveys can play such a crucial role in the success or failure of a building or demolition project it is critical that they are carried out carefully by the correct people. There are different branches of site surveying and each one will have unique certificates associated with it. Finding surveyors with these specific qualifications will certainly be beneficial.

When selecting a company to undertake the surveying work required for your project it will be sensible to choose a business 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 past projects. It may also be worth thinking about how a company can deliver the survey information, i.e. in 3-D models or CAD ready formats, for ease of integration with other members of the project staff.

Who will use the Survey Information?

Once 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 mostly depend on the job roles being performed, but can also rely on the stage that a project is at. There will be much less need for materials information half way through construction for example.

Project Planners

Project planners will usually need access to all of the information collected by a topographical survey, although they will particularly need to use information regarding 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 project.

Demolition Experts

Demolition organisations 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 individual requirements, demolition workers will generally need to know about the fundamental structure of a building and the materials it is made out of. They will need this information before demolition can take place.

Site Engineers

Construction engineers on-site will be mainly interested in the survey data about the relief and topography of the site. It is normally the case that they will want to assemble 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 stable foundation for any building. They will want this information prior to and during the construction stage of a project.