Pre-Demolition Site Surveys
The demolition industry has a certain reputation for being a harsh environment in which brute force takes priority over calculated thinking; however this image is far from correct. There is a substantial amount of work that goes on behind the scenes of the demolition and construction industry that is firmly rooted in the academic arena.
One branch of this unnoticed work is site surveying, or more specifically pre-demolition and post-demolition topographical surveying. This sort of work demands a great balance of specific technical understanding as well as experience of the industry and a natural intuition for the intricacies 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 chart the naturally occurring and man-made features of a particular landscape to a high degree of accuracy.
Topographical surveys could be carried out on a very wide range of environments, from open countryside to urban developments and across a variety of reliefs and land surfaces. Surveys can be developed to take into account a great many factors, such as ground variables or vegetation, and as such can be used for a number of tasks.
Common Applications for Topographical Surveys
Probably 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, elevations and ground surface, all of which will have been collected 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 companies are looking to construct 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 essential part of any application for planning permission too.
Surveys also 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. Businesses in these industries will use surveys to plan their projects, but also to ensure that they can guarantee the safety of their workforce on site. As a result, topographical surveys are often a legal prerequisite for these types of projects.
Many construction and demolition companies in the UK perform demolition surveys for projects they are working on.
Types of Survey
The arena of topography addresses a large number of physical characteristics so it is beneficial to identify 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 reviewed 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. Whilst the information gathered by the survey will be very accurate, and might be very extensive, the purpose of these surveys is to give a site summary. They will often be the first type of topographical survey that is carried out on a project.
These surveys will usually 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 may also include a level survey that will measure the elevation of the terrain and the numerous gradients that exist.
Building Surveys
Building surveys are more generally concerned with man-made constructions on a site, including the surveying of special machines and even infrastructure characteristics. This type of survey is more regularly associated with the demolition industry since it can give a detailed plan of the building to be demolished.
A building survey will almost certainly include a measured survey, which involves creating a precise plan of the external and internal proportions of a structure. Depending on the requirements of the job, a measured survey could provide basic 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 always include the details gathered by the types of boundary and building surveys described above. This information will be required so the demolition company can plan a demolition that is both satisfactory and safe. Often these surveys will also be legally required.
Surveys will often include information about the power services that are present on a site before any demolition or construction work takes place. This is an important safety factor since any unmonitored destruction to pipes and cables carrying water, gas and electricity might be very dangerous. The information can also be used to plan new buildings, based upon the existing supply of these ammenities.
Another aspect of the site survey will often be an audit 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 getting an accurate audit of site materials the construction company can more accurately determine the need to import building materials, or they can re-use the materials on a different project. These surveys can be made pre-demolition as well as post-demolition.
Topographical surveys and resource quantity reviews form one particular branch of demolition services provided by contemporary organisations that conform with industry best practices.
Importance of Site Surveys
Maybe the most important reason to undertake a topographical site survey is to ensure the safety of the individuals who will be doing work on the site. The industries 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. Taking a detailed topographical survey can help to mitigate safety risks of this nature.
Another critical reason to get a suitable survey done is to highlight 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.
The inventory of site materials, 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 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 managers. For example, if the gradients on a site would be prohibitive to particular vehicles or equipment then a new entry 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 construction 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 stage of a project since the equipment is both costly and sensitive. It is therefore wise to move this equipment off-site during demolition.
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 effective data collecting to take place for a post-demolition survey, and retains a single point of contact for anyone who needs the topographical survey information.
Who can Perform Site Surveys?
Since topographical site surveys can play such a critical role in the success or failure of a construction or demolition venture it is critical that they are carried out thoroughly by the correct people. There are different divisions of site surveying and each one will have specific qualifications associated with it. Getting surveyors with these specific skills will certainly be advantageous.
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 past projects.
Who will use the Survey Information?
When 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 what pieces of information will largely depend on the job roles being executed, 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 need access to all of the information collected 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 inventory before they can plan the construction phase. The more information that can be made available to project planners will aid the smooth running of the venture.
Demolition Experts
Demolition companies will want to know about the internal and external characteristics of any building or structures that they are arranged to take down. Whilst every job will have individual requirements, demolition experts will typically need to know about the fundamental framework 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 terrain. It is normally the case that they will want 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 steady foundation for any building. They will want this information before and in the course of the construction stage of a job.
