A site investigation and a topographical survey are two distinct types of surveys that are carried out for different purposes.

If you are considering a major alteration to your home like a basement we recommend that both a topographical survey and a site investigation be completed. This might seem like overkill but these two investigations will identify anything that might derail your project or something that may prove expensive in the future if not dealt with during the early stages.

A site investigation is a process that involves the collection of information about a particular site or location to determine the suitability of the site for a specific purpose. The investigation is typically carried out by a team of specialists, including geologists, geotechnical engineers, environmental consultants, and others. The site investigation includes soil sampling, analysis of groundwater conditions, and testing for the presence of hazardous materials or contaminants alone with foundation recommendations. The aim is to understand the site’s physical and chemical properties to determine its suitability for the proposed use.

On the other hand, a topographical survey is a survey that involves mapping the features of a particular piece of land. The survey provides a detailed plan of the land, highlighting any significant changes in elevation, such as hills, valleys, or other terrain features. This type of survey is typically conducted to identify and locate existing natural and manmade features such as benches, traffic barriers, bollards, post boxes, streetlamps, traffic lights, traffic signs, bus stops) and manhole covers. Particularly in urban areas, there will be a huge amount going on underground with water and power supplies so the location of utilities is especially important.

The overall purpose of the topographical survey is to accurately report ( within + or – 2mm) any and all limitations or considerations needed relating to the site of the proposed development. An architect, structural engineer, or developer can then assess the feasibility of the proposed basement or development, as well as decide what the best way to proceed would be; if there are identified issues they maybe design a workaround.

In summary, the main difference between a site investigation and a topographical survey is that the former is focused on determining the suitability of a site for a specific purpose, while the latter is focused on mapping the features of a piece of land.

f you are considering a basement, then speaking to a structural engineer at the very earliest stage is advisable. We have lots of experience with commercial and residential basements and will ensure you understand all that is required before you spend money on designs or planning.

Give us a call on 01993 225 085 or email rhys.skym@swjconsulting.co.uk for a no-obligation chat.