As a professional CAD drawing services partner for many construction firms, we are very familiar with the different type of construction CAD drawings that are used. However, if you are new to the industry, then you may not be aware of the differences.
We’ve pulled together this information to help you to understand the different CAD drawings that are used in construction and the role each drawing type plays during the construction process.
“Construction Drawings” is the term used to describe the collection of preconstruction drawings which represent a building as a whole. They are the record of the building design and should include detailed information about every element of the building such as:
- ceiling plans
- interior details
- MEP design
- structural details
A design team usually produces construction drawings, and there will often be several drafts of the drawings produced in the design phase before the final draft is agreed and becomes part of the contract. Any contractor who works on the project will then be bound by the construction drawings, as well as other construction documents.
To sum up, then, construction drawings:
- are produced by a design team
- are official contract documents
- are subject to change orders, mark-ups and redlining throughout the construction process
- are created before the project is bid on usually
- represent the design of the building as a whole
One type of construction drawing that we deal with quite often are so-called “shop drawings.” These are drawings created by contractors and vendors which help to define the design of specific building components further. They are usually concerned with the MEP components and show details of cabinetry and other elements. They are essential for planning the prefabricated components of buildings, and so have become more commonly used with the increased use of modular construction technology and prefabs.
As with construction drawings, shop drawings are created before any construction starting and should be agreed by the design team, contractors and sub-contractors before work begins. They don’t usually form part of the official contract and can sometimes be produced later on in the project as well.
To sum up then, shop drawings
- are produced by the contractor and sub-contractors
- are not official contract documents usually
- are created after the project is awarded and before construction begins
- May be subject to mark-ups, change orders and redlining
- Represent the components of the building
‘As-built drawings” are drawings that show the building and its components as it was constructed. As we mentioned above, construction is a complex process, and the end building often doesn’t represent the building that was on the original plans.
Therefore, As-built drawings, represent the final construction of the building exactly as it was built. They are drawings which are produced by contractors and subcontractors after the building is completed.
As-built drawings are useful for showing building owners what they need to know about maintenance, repairs, updates and renovations. They are usually created from the original construction drawings and can be very time-consuming to complete. However, the technology available to us today means that it is possible to produce as-built drawings quickly and accurately and update them in real-time as the project proceeds.
To sum up, As-built drawings:
- Are produced by contractors and sub-contractors
- Are produced after the project is completed
- Are sometimes part of the construction project mandate, but are not usually part of the contract documents
- Represent the building and all of its components as a whole, as it was actually constructed
- May be subject to change if the building is renovated
As you can see, all of the three types of construction CAD drawings are important and understanding the difference between them can help construction workers make better use of them, and organise their projects more effectively.