What Does It Cost to Create a BIM As-built?

If you happen to be a service provider who documents buildings it probably wont be long before youre confronted with the inevitable question from a prospect, What does it cost to create a BIM as-built? Im usually asked this question with little-to-no information about the building that needs to be documented. If Im lucky, the prospect will tell me the size of the building, maybe the number of stories, but often, thats about all theyll offer. Usually, when they sense my hesitation in providing an answer, theyll add Just a ballpark figure will be fine. I wont hold you to it.

This question is often very revealing about the level of understanding, or lack thereof, one has about BIM (Building Information Modeling) and building documentation in general. Some general education is usually appropriate at this point. Ill typically start off by explaining how documentation with a laser scanner is based on maintaining a clear line-of-sight. The more obstructions there are, the more setups will be required, thus increasing the amount of field time and the post-processing time required to complete the work.

There is a big difference in documenting a 100,000 square foot warehouse building and a 100,000 square foot office building. The warehouse building may only require a dozen or so laser scans, whereas an office building of the same size may require well over 100 scans. To top it off, Ill ask whether they need the above ceiling SMEP (Structural, Mechanical, Electrical, and Plumbing) systems documented. If the answer is yes, then you can potentially double the number of scans required. Usually at this point in the discussion they are beginning to understand why their question isnt so easy to answer.

To begin to answer their question additional answers must first be provided. There are many factors that define the amount of work effort required to deliver a BIM as-built, and thus provide the proposed cost. First, the service provider must understand what the prospects needs are. Ive found obtaining the answers to the following series of questions will often give me enough information from which I can then begin to answer the prospects question, What does it cost to create a BIM as-built?

1) Where is the project located?

It is helpful to look up the buildings satellite imagery to gain an understanding of the complexity of the building. This will also answer the question, what kind of travel expense is expected to be incurred?

2) What is the building square footage and number of levels?

While square footage alone doesnt give enough information, it does begin to tell the rough order of magnitude of the work effort. Be sure to clarify if the number of levels includes rooftop penthouse spaces, basement levels, underground parking, etc. It is common for these spaces to go unmentioned.

3) Is the space occupied?

Occupied buildings will generally result in a slower workflow. People, furniture, fixtures and equipment create obstacles and impediments to getting survey work completed.

4) What type of accessibility will be granted to the survey crews?

Will the accessible hours be normal business hours, evenings or weekends? What are the security clearance requirements? Again, this can play a big role in how quickly on-site operations can be completed.

5) What are the required deliverables?

Often a prospect will say they need their building laser scanned, but what they really mean is they need it documented. Ill usually try to clarify if they need actual point cloud data. If the answer is no, then that tells me I can use whatever means and methods to perform my documentation. Laser scanning may not always be the fastest and most cost effective method.

6) What Level of Accuracy (LOA) is required?

Generally speaking, the lower the level of accuracy that is required the more tools Ill have at my disposal. For some jobs, a hand held laser range finder may be perfectly suitable, whereas other jobs may require a survey control network with total stations and laser scanners.

7) What Level of Detail (LOD) is required?

Is the intended purpose meant to satisfy simple generic massing, construction documents, lifecycle purposes, etc? The AIAs (American Institute of Architects) Document E202 can be used to help define the appropriate level of detail in a BIM.

Existing record drawings, photos, and a job walk are also very helpful. Buildings are generally comprised of complex systems. Rarely will any two buildings be alike. Because there are so many variables in both the structure being documented and the requirements of the deliverables it can be very difficult to answer the question at hand without more detailed information. With some basic education it usually isnt too hard to get a prospect to understand why it is difficult to just throw out a ballpark number on what it may cost to create a BIM as-built. Ive found, though, that if you are tempted to throw out a number, be prepared to keep with that number. No matter how many times the prospect tells you they will treat it as a rough order of magnitude, experience has dictated that they most always expect something very close, if not lower, to what you say.