As-Built Documentation- What is it?

Why As-Built Documentation?

The As-Built model represents a structural system as it was built. The result is a uniform overall model that can be used as the basis for an operator model. The model is composed of the steps of As-Built documentation and As-Built control. The model, thus, describes the process and the subsequent actual state of a constructed building or facility.

The As-Built documentation of a construction site is always a major point of contention at the end of the project duration when construction companies have to hand over the data and information to the client. Often, this handover does not take place and cannot be fully guaranteed with conventional methods. The As-Built documentation ensures that the construction site is documented in the form in which it was built. On the other hand, the handover of the documentation to the building owner and later to the company can be carried out easily and painlessly for everyone. The AS-Built documentation also creates more transparency between the client and the construction company, as every detail has been documented and can therefore be more easily verified. Thus, the AS-Built documentation with the technical possibilities is not only new but also offers the possibility to fully satisfy all the stakeholders involved, regarding the building documentation in the future.


What is As-Built Documentation?

First, one starts with the As-Built documentation. Here, the construction progress of the building is regularly documented. Thus, the As-Built documentation is overall documentation of a building or a facility that correctly and completely describes the state of affairs at the time of its acceptance (As-Built). The documentation serves as the basis for defect management on construction sites and in operation, for As-Built control and the digital twin. The As-Built documentation can also be used for subsequent inventories of buildings. Documentation is followed by control. The check is carried out to compare the recordings from the documentation with the planned building data (e.g. BIM model or 2D plans). In addition, the tolerances in the building are taken into account. The aim is to ensure that the model corresponds to the actual state.

How Does As-Built Documentation Work?

In AS-Built documentation, the object is measured using various 3D laser scanning methods, depending on the structure or facility. As an application example, drones or even mobile scanning methods can be used in the shell construction phase to record the constant progress of the structure and thus create a 3D point cloud. In the further course of a project, such as after the installation of the building services, it is possible to use precise, terrestrial, or fast, mobile scanning methods. In this way, the construction process is tracked in stages and documented sustainably. The generated point clouds are then superimposed in validation systems with the 3D model from the planning or execution phase and thus controlled. The generated point clouds and 360-degree images can also be used and further developed to prepare the operator model or directly for the digital twin.

Examples of As-Built Documentation

AS-Built documentation is suitable for any construction project. Entire buildings, facades, or even individual rooms can be illustrated with it. With the help of the different surveying technologies, the right technology is available for every project. Plants, machines, or even supply facilities and ventilation systems can be documented with the model. Generally, the renovation of existing buildings, building expansion to further parts or even, an entirely new building are among the application examples of AS-Built Documentation. If you still have no idea what AS-Built documentation is, please read our case study on Viega World. In it, we describe the project itself, the challenges, and the added value created by the AS-Built Documentation.

Need a Reference?

Click here for the As-Built Documentation of Viega World.

How Can I Get Started With As-Built Documentation?

Once the decision has been made to use AS-Built documentation in a construction project, milestones for recording with surveying technologies should be set in advance. It must be determined in advance, at what time, where, and how it is to be documented. In BIM projects, it must be ensured as early as possible that the AS-Built documentation is contractually agreed with the executing company and is also included as part of the “Client Information Requirements” (AIA). The executing partners are also responsible for describing the exact process in the BIM execution plan (BAP). When recording the as-built condition, the construction site or the existing building should be freely accessible and free of people, if possible, to avoid subsequent, time-consuming editing of the point clouds and 360° images. Should people and faces be recognizable in the pictures, we have automated pixelation of the pictures using face recognition software. In principle, large construction sites are recorded in stages. The buildings are recorded after each construction progress.

Process of As-Built Documentation

With AS-Built documentation, also called construction site documentation, the desired building is surveyed several times using different techniques. We primarily use the NavVis M6 Trolley for indoor and drones for outdoor surveying. In addition, a total station is used for the calibration.
The process of AS-Built documentation begins with an inspection of the building site, initially without technology. Our surveyors look for possible locations for the control points when they first inspect the building. These are particularly necessary for buildings with several floors. This is because control points ensure that the individual storeys fit together in the later model and thus that the entire building is georeferenced. In addition, our surveyors look to what extent it is possible to scan the construction site and at which points there could be problems.
Once the positions of the control points have been determined, they are measured once at the beginning with a total station. The control points are then summarized in an overview. The resulting control point overview is important because the control points define the positions at which measurements are to be taken. Normally, a construction site is measured repeatedly every two to three weeks. For the different measurement times to match, it is important to measure exactly at the same point. With the help of the control point overview, everyone can find the control points and thus guarantee a high-quality survey.
The Trolley surveys the entire area with a 3D laser scanner and six high-resolution cameras. For more information on the Trolley and other technologies, see our technology overview.
Afterward, the data is read into a computer and processed further with the help of software. The images are converted into panorama images. The survey data is used to create a point cloud, which has to be partially processed and cleaned up. If present, visible faces in the images are pixelated. Finally, the entire model is compressed to make it available online in an indoor viewer.

What are the Advantages of As-Built Documentation?

Defect Management

The connection to a defect management software enables the localization of defects in the BIM models and exchange via the BIM Collaboration Format (BCF).

Defect Detection

Thanks to the as-built documentation, errors are identified and corrected at an early stage to avoid the costs of troubleshooting.

Quality Management

The AS-Built documentation ensures a higher quality of the building, as fewer defects occur due to early detection.

Control of Compliance

The documentation gives a better overview of what is missing and which points need to be complied with.

Who is the As-Built Documentation For?

With the AS-Built documentation, construction companies have the opportunity to implement effective defect management, keep a close eye on the construction processes from everywhere, and ensure better project and risk management across many construction sites.
Documentation and transparency are of great importance for builder owners and investors. They want to carry out a comparison of the actual state with the planning. In doing so, problems can be identified and rectified and, if necessary, the planning can be revised later. In addition, the AS-Built documentation is the basis for transferring the data to the operator and for facility management.

The documentation gives banks and insurance companies a rough indication of how much the project will cost and which insurances are necessary to optimally protect everything.

The public sector and the public client can use AS-Built documentation to manage large properties and many projects remotely, ensuring that projects are delivered on budget and on time. The AS-Built documentation makes it feasible to manage and operate large and many properties.
An As-Built drawing is the most important source for making changes or adjustments. When moving from one phase of construction to the next, documentation makes it easier for the contractor to plan actions that may arise. This makes it easier to identify and prevent problems before they occur. With the help of laser scanning, conventional work such as manually checking dimensions and distances can be digitized and accelerated.
To complete a final purchase, revision documents are essential. These contain important information about the property that is being sold. The documentation can be used as a basis for future renovations.

How is the Information in the As-Built Documentation Processed?

Exact Classification

The information can be precisely classified in terms of space and time. This creates a clear structure.

Granting Access

People who are connected to the building can be given access authorization. This way, anyone can find and retrieve the information directly when it is needed.


For international projects, the documents can be stored in several languages so that everyone can understand the information.


Various forms of data can be stored in the model, such as written documents, audio or video notes, photos, etc.

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