As-built surveys and GRB
In an as-built survey, how a project was actually built is recorded after the works have been completed. These measurements provide a correct and up-to-date representation of the realized state and form an important link between execution, administration, and spatial planning.
In this article, we explain what as-built surveys are and how they relate to the Large-scale Reference Database (GRB).
What are as-built surveys?
As-built surveys are accurate measurements of a construction or infrastructure after the works have been completed. These record, among other things:
- location and dimensions of buildings
- foundations and structural elements
- pipes, utilities, and paving
- deviations from the original design
The goal is not to design, but to objectively record what has actually been realized.
Why are as-built surveys important?
Quality control
As-built plans demonstrate whether the execution complies with the approved plans and permits.
Correct documentation
They form a reliable basis for future maintenance, renovations, or expansions.
Legal and administrative value
As-built surveys can serve as evidence for:
- permit files
- assessments
- disputes or regularizations
What is the GRB?
The Large-scale Reference Database (GRB) is a digital base file used in Flanders for spatial data. It includes information on:
- buildings
- parcels
- roads and infrastructure
- waterways and public domain
Governments and utility companies use the GRB as a reference for planning, management, and policy.
The connection between as-built and GRB
As-built surveys often form the source data for updating the GRB. When new buildings, roads, or infrastructure are realized, as-built plans ensure that:
- digital maps correspond to reality
- spatial data remains up-to-date
- property and infrastructure information is correctly managed
In this way, the as-built survey forms the bridge between on-site execution and digital spatial databases.
How are as-built surveys performed?
Depending on the project, this can be done using:
- a total station for high accuracy
- drone surveys for larger or hard-to-reach areas
- a combination of measurement methods
The choice depends on the scale, required accuracy, and the purpose of the survey.
Want to know more?
Do you have questions about as-built surveys or their role within GRB registrations?
Please feel free to contact us for further information or advice.