Movement monitoring surveys involve the placement of fixed targets on to a structure. These targets are then precisely monitored using a total station surveying device. Once the results have been processed the target’s movement in both plan and elevation can be accurately plotted and reported.

The monitoring survey company uses total stations to undertake this task. A total station is used as a highly accurate piece of equipment that can measure horizontal and vertical angles very accurately. A total station is combined with a distance meter which combined with the angular measurements triangulates the surveyed positions. Some total stations can accurately measure very long distances (500 metres plus).

The survey targets that are measured are usually in the form of reflective stickers or survey prisms. The targets serve a simple purpose of being a fixed location that allows accurate, repeatable surveys over time. The targets are securely fixed to items to ensure consistency over time. The fixing methods are usually glue or mechanical fixings.

The data gathered by the total station is processed and then presented in report and graph format. This gives the client a clear idea of what is going on with regards to movement in plan and elevation. Trigger values can be set that automatically trigger certain actions such as ceasing works on site until the movement issues have been resolved.

Monitoring surveys are utilised on a range of different sites from small insurance claims to large national infrastructure projects such as Crossrail in London.

A fixed position monitoring survey is the method of monitoring a set location on a wall / structure and observing movement in the horizontal and vertical planes over time. 

Fixed position monitoring is used for a number of projects ranging from small basement projects to large infrastructure projects such Crossrail tunnel project under London.

The monitoring project always starts with the initial setup of the monitoring targets and local survey control network. The targets are fixed to the structure in the pre-designated locations utilising either glue or drilled screws.

Without a fixed monitoring point to resurvey each time the consistency will be poor or non-existent. Fixed points are installed on to the structure and usually consist of survey prisms or reflective target stickers. When using prisms they are typically secured using screws drilled into walls or using high strength glue.

A local survey control network also needs to be installed. This involves placing survey targets (prisms or reflective survey points) away from the site. These are used by the total station as a way of calculating it’s precise position each time a monitoring survey needs to be undertaken.

A monitoring survey is undertaken using a piece of equipment called a total station. A total station is a high accuracy optical instrument that is used to measure distances and angles. Total stations are usually mounted on tripod legs whereby the operator can look through the lens and record survey points. In some cases, automation is required If so a total station can be left in a safe location and operated remotely.

At each survey interval, the total station has to be set up using the local control network. Once set up accurately, the monitoring survey process can be undertaken. Each monitoring point is precisely surveyed using the total station and recorded to the instrument.

Once this data has been reached the office, it is uploaded to the monitoring survey software which can generate data to illustrate movement (or lack of) over time.

A monitoring survey process is usually undertaken on the advice of a professional such as a Structural Engineer or Party Wall Surveyor. If a building or structure is a risk of movement then a monitoring survey is usually commissioned.

Typically monitoring surveys are commissioned when undertaking heavy construction works next to existing buildings. Some examples include:

• Piling works
• Underpinning
• Basement excavation
• Demolition

A monitoring survey scheme can also be commissioned where an insurance claim is being checked.

It is very important that you have at least one survey prior to any works being undertaken. This is to ensure you have a base reading to compare any future readings against. If you start after works have taken place then you may miss any initial movement in your structure.

During major operations such as digging, underpinning, concrete pours etc then we recommend a survey every week until this is completed.

Once the intense, heavy works have been completed then this can be reduced to say a monthly visit until the internal fit out works begin. Once the internal fit out (plastering / painting / decorating) has begun then any movement will likely be limited so the monitoring can cease.

We recommend speaking to your project manager or party wall surveyor about monitoring intervals. Some projects require more frequent intervals whilst some specify less!

We operate both nationally and internationally, we have been as far as Liberia in West Africa to undertake our survey service.

However, we typically operate in London & The South East. This includes Kent, Hertfordshire, Sussex, Surrey, Suffolk and Essex.

Monitoring survey data is usually presented in report and graph format. The reports will outline movement over time. It’s common to see reports showing movement compared to the previous set of readings as well as the initial set of readings.

Graphs can also be produced to show the movement in a graphical sense. Graphs can help show when movement started occurring.

Movement monitoring surveys are an good way to help prove or disprove that movement within a structure has been undertaken. This can help with future claims either made for or against.

Diligent contractors ensure that they minimise movement as a result of construction however claims from neighbours can still arise.

The movement monitoring reports produced can demonstrate movement or lack of over time. This can be used in counter claim situations where by neighbours insist that damage has occurred.

Another purpose of monitoring surveys is from a safety perspective. If a building is moving during construction works then this can be identified. If a movement exceeds a certain level then this can be flagged. The potential source of the movement can be found and mitigated against prior to any problems that could potentially endanger.