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as-built drawings and redline drawings

Red line vs as-built drawings

Redline drawings and as-built drawings are useful for updating projects after changes during the construction phases. Read the article and find out more

During the construction phases, a project can end up going through major organisational changes. Safety measures may need to be tweaked up and so document keeping and auditing need to be managed appropriately with methods that can highlight these variations.

In this article, I’ll go through the details of two main solutions used for work variations management. To be able to address and resolve any type of inconvenience that may arise and also improve collaboration with colleagues, I really recommend this free BIM management system.

What does redline mean in construction?

During the execution phase, in general, a project can undergo substantial changes. These changes need to be recorded in official documents and correctly stored too. The redline represents all these different changes as they become necessary during the construction stages.

Redline, as a change annotation and highlighting method, comes from the traditional red pen mark ups used on old paper drawings to underline errors and/or corrections: still considered an efficient way of drawing immediate attention to updated info or notes on technical documents because where there’s a red outline or a note, you know that there’s some sort of change notice there.

It’s always good pratice to discuss the need to introduce changes with the project manager to avoid communication gaps and errors. In some cases, work variations that may not comply with local or national legislation so it’s always a good idea to analyze possible solutions in ccordination with the technical board.

Redline indications and relating guidelines should always be added to the official designs and construction documentation with clear descriptions so as to obtain an as-built drawings that fully reflects reality.

What are as-built drawings?

Let’s see more about the different forms of graphical representations and take a closer look at what as-built drawings actually are.

As-built drawings are official drawings drawn up by the technical team and are simply composed of ther original design merged with any required changes identified by means of redlines; they then show how a certain project was carried out.

These drawings are delivered to the competence offices for validation with respect to the changes made or for those to be authorised.

Therefore, the correct process is to:

  • creation of redline drawings by the general contractor, showing all changes to be made to the project;
  • drafting of the as-built drawing so as to have the official project always updated.

What is the difference between “redline” and “as-built” drawings?

Based upon what we’ve discovered so far, it’s quite easy to understand how redline markups and as-built drawings aren’t the same thing. In fact, there are considerable differences that we can summarize as follows:

  • the as-built drawing is an official document (or set of documents) to be delivered to the competent offices, while the redline drawing is used to identify on-site changes that have already been made or to be introduced in the near future;
  • as-builts are drawn up by the technician, while the redlines are generally produced by the construction company;
  • changes annotated in the redline are indicated manually (directly on site) while the as-built drawings are produced in digital format;
  • the as-built is an official document that must be signed by the technician, while the redline is valid when changes are confirmed by a manager.

What are redlines on an as-built drawing?

As soon as an as-built design has been approved it becomes the official reference design. The originating project drawings are therefore replaced by the as-built drawings and annotations because they include all introduced changes as specified with the redline markups.

Can youmake changes to the as-built with new redline drawings? The answer is yes.

Since the as-built is the official document to refer to, it’s also the document within which all changes are highlighted. This can be done over and over again until completion of works defining the final project which become the fully consistent photograph of the as-built construction or infrastructure.

At this stage, it’s crucial to use a BIM management system to maintain the intense information exchanges between collaborating parties and the various professionals involved.

Advantages of As-Built Drawings

Let’s take a look a the main advantages of as-built drawings.

  • they are of great help to know how the entire work is organized in all its parts (for example, knowing where and how all the technical systems are functionally organised);
  • they can avoid errors due to inconsistent drawings ensuring that everyone follows the same updated documents;
  • they act as an official registry for clients, technicians, companies, etc.);
  • they can optimize future maintenance/repair operations forming a basis for reliable survey data.

So, you can know see how important it is to have a clear picture both how the building should be and how it really is in all its aspects.

The Benefits of Redline Drawings

As mentioned above, redline drawings are very important to update documents with respect to changes made or to be made.

The advantages of this method of identifying errors or changes are many:

  • accuracy of the changes made to the official document;
  • date of each change, so as to have an orderly history of all the changes made;
  • indication of additional elements that are not shown on the project drawings;
  • possibility to write down all relevant information directly on site.

In conclusion, given the different definitions and advantages of accurate redline drawings and documented changes to our original construction drawings, you can see how useful it can be to optimize information exchanges to the as-built drawings.

Finally, I recommend that you take advantage of the potential of a BIM management system to optimize collaboration with your colleagues and increase the quality of the entire project.