What is as-built documentation and what is it used for?

As-built documentation is the set of information depicting a building, that is updated after its construction. Let’s find out what it’s for

What is as-built documentation? How is it used? Why is it important?

As-built documentation is the documentation of the existing building that gets updated and verified after its construction. In this article we will see what it is in detail and why it is so important.

On the bounce, if you are interested in the topic, I also recommend a BIM management system to manage 3D models and as-built documentation for free, in a simple, safe and collaborative way.

What is as-built documentation?

The “as-built” documentation is a set of data and 3D models that depict the building as it was actually built and that are delivered to the client upon completion of the job.

As-built data includes all changes and additions made througout the construction process, compared to the initial design. They usually include the exact dimensions, characteristics and geometries of all elements of the building, as measured at the end of the works (as-built survey). The geometric survey can be done with different tools: laser scanners, drones, total stations, etc.

It is common practice to work on as-built documentation already during the construction phase and update it when changes are made. In this way, you’ll ensure that the virtual information model is consistent with the real one, and that contractual clauses are being responded to.

BIM model with as-built documentation

As-built documentation has many applications in the construction sector, especially for:

• contractors who need up-to-date data to demonstrate that they have carried out the work in response to the project;
• property owners, buyers and managers who need access to all building data (from the original design to the current state) in order to have greater guarantees or to better manage maintenance, renovation, etc.
• companies and professionals who will work on the building in the future and who need updated and complete models
• banks and insurers who must, for example, be certain to guarantee loans and mortgages.

As-built documentation is required for any type of project. Entire buildings, facades or even single rooms can be illustrated and can concern any type of process: from the renovation of the systems in an existing building to the ex-novo design of a complex of buildings.

Usually, the contractor who has carried out the work also has the burden of producing and delivering the as-built documentation to the client. Before its delivery to the customer, the documentation must be accepted and definitively approved by the professional in charge.

The benefits of as-built documentation are:

• defect management – the connection to a BIM validation software allows you to manage and control all the IFC data of each information exchange and generate validation reports that ensure the quality of your model;
• defect detection – errors are identified and corrected at an early stage to avoid that the troubleshooting costs become unsustainable;
• quality management – guarantees a higher quality of the building, as defects are identified and fixed before the delivery of the work;
• compliance check – the comparison between the real and the virtual model allows to verify compliance and update the documentation in case of inconsistencies.

Moreover, the as-built documentation ensures greater transparency between the customer and the company that carried out the work, since every detail is documented and can therefore be verified more easily.

What are the most common examples of as-built documentation?

Traditionally, the most common examples of “as-built” documentation are 2D CAD drawings.

This practice is evolving with the advancement of BIM methodologies and with the increasing use by technicians and industry professionals of intelligent 3D models and common data environments.

An as-built 2D CAD drawing, such as a house plan, represents the accurate dimensions of each environment through a drawing made of lines. This means that the 2D plan does not contain additional information on the elements represented (type of flooring, materials, cost of the intervention, construction times, etc.).

A BIM model, on the other hand, is made of intelligent parametric objects to which all the information necessary to the project’s life cycle can be associated.

When managing an as-built BIM model, you can select any object (a window, a pillar, etc.) and view, precisely, the information associated with it. In addition, you can always implement the template with new information or update existing information if changes occur over time. The as-built model is, therefore, always updated and complete and constitutes a rich information container that can always be consulted by interested professionals and contractors.

Data management, however, can be extremely complex without an adequate tool because BIM data:

• consist of different file types;
• are often distributed over multiple software solutions, making sharing and collaboration very difficult;
• change continuously as the project evolves, making it difficult to keep track of all the latest changes.

The only way to manage BIM data effectively is to use a BIM data management software, a cloud-based platform that helps manage BIM data in a single centralized location, directly online and in real time.

Morever, it gives all interested parties access to the latest version of the BIM model, facilitates the monitoring of changes and avoids misunderstandings and delays during construction.

Why is as-built documentation required?

At the end of the job, the work carried out never perfectly corresponds to the project model.

This happens because the conditions agreed in the project may slightly change or be subject to error. Changes to the budget, estimate errors and unexpected events that require redesigns and reprocessing may occur during the project.

Even the most fluid construction process and the most advanced BIM or VDC methodology can produce a building that can differ from the original design even if to a small extent.

Therefore, the project model and the information associated to it need to be updated according to the actual status. The expected result is a model that is consistent with that built and represents an actual digital-twin of the existing construction.

In summary, as-built documentation is useful for:

• demonstrate that the final result fully complies with the contractual clauses;
• have an updated information model that corresponds to the actual state of the construction;
• have a reliable starting point for future maintenance work;
• guarantee and protect the interests of customers and contractors;
• provide professionals, who will intervene in the future, with up-to-date and complete information relating to the product.