A person’s fear can keep them from doing what they want to do. For example, a fear of heights may keep someone from a trip up to the top of Seattle’s Space Needle or a fear of drowning may keep someone from swimming on the hottest day of the year.

A subcontractor may want to buy an expensive piece of equipment but can’t afford it or wants to bid a big job yet can’t because it requires a level of bonding he can’t provide. These are all examples of a constraint, which is defined as “something that limits or restricts someone or something.”

As subcontractors, we are always waiting for something to get done so we can start our work. We might have to wait to install framing until concrete is poured or wait for a plumber or electrician to install their work before we can install ours. For the most part, schedules are created in a sequence allowing one trade to follow another, yet that’s not always the case as a result of constraints.

When we bid a job, it’s usually based on a schedule that allows our work to follow a proper sequence. Once we get a job, we might find for a variety of reasons “our schedule and sequence” is altered daily, weekly or monthly. These schedule deviations are usually the result of constraints.

all in agreement

Actual Schedule

If you were able to overlay the schedule you based your bid upon and the actual schedule of the job you’re doing, you will find one constant and that is your completion. Completion dates rarely change no matter how much your work was delayed by constraints. As a result, the owner and general contractor expect you to take any measures to complete your work per the original completion date.

Most subcontracts say the general contractor and/or owner have total control of the schedule and have the right to modify the schedule at any time. However, subcontracts don’t say that subcontractors aren’t entitled to additional compensation for schedule changes.

The key to being compensated is to know why your schedule changed. In most cases, schedules change because of job-related constraints. A subcontractor’s work may be delayed as a result of a preceding trade’s work not being done or a delayed submittal, failed inspection, open RFIs, build-design changes, weather or other owner/contractor related changes.

Most constraints are avoidable, meaning someone could have eliminated the problem prior to it actually causing a constraint. An unavoidable constraint might be weather, a freak accident, fire, flood or some other issue that could not have been anticipated.

A common problem for subcontractors is not being able to finish an area as a result of some other constraint. Oftentimes, an owner will issue a design change related to an area you’re working in and as a result, you can’t finish your work because the owner wants the change—meaning you will have to remobilize or come back to the area to finish your work once the change is completed.

If You Could

If you could track all the constraints on a job—and show each constraint on a schedule—you would find that constraints impact you in many ways. Here is a brief list of the impacts that constraints can cause:

  • Loss of momentum
  • Loss of productivity
  • Delay    
  • Acceleration
  • Manpower ramp up
  • and down
  • Performing work out
  • of sequence
  • Fragmentation
  • Phasing
  • Demobilization
  • Remobilization
  • Extended durations
  • Trade stacking
  • Disruptions
  • Inefficiencies
  • Tool/equipment utilization
  • Additional supervision
  • Reduced revenue

Again, a subcontracting constraint is, “anything that limits or restricts someone or something” from doing what was originally estimated and planned for. The list on page 74 describes the impact constraints can have on a subcontractor. One constraint may only result in one or two of the impacts. Another constraint may result in several of the impacts; it all depends on the timing and severity of the constraint.

I enjoy helping subcontractors determine if they are entitled to additional compensation as a result of owner/contractor impacts. In these situations and in almost all cases, subcontractors lose money as a result of constraints. Meaning the schedule was impacted for a variety of reasons, which resulted in the subcontractor having to perform the work differently than the original schedule. 

In order to find out why the subcontractor’s work was not done per the original schedule, I have to ask the question “Why?” about a thousand times, depending on the size of the job. “Why couldn’t you start the area? Why couldn’t you finish the area?” These are all questions I have to ask over and over again.

What I’ve learned in this process is that subcontractors understand that their work was delayed or accelerated but they don’t always know why, and in most cases the common thread is owner changes. I believe that in the heat of the battle and wanting to please the client, most subcontractors lose sight of the “why” and focus on getting the job done. Another thing I’ve noticed is that a lot of subcontractors let owner and general contractors’ problems become their problems, and most of their problems are related to constraints.

Think and Communicate Differently

Consider changing the way you think by looking at all schedule impacts as constraint issues. When you talk or write about delays or reasons (why you couldn’t do what you planned), try using the word “constraint.” Teach project managers and field supervisors that most schedule issues are the result of constraints and finally make it a standard practice to track constraints.

I created a simple Excel application that gives managers the ability to track constraints.  You can download the file by clicking here. After you download it, you will see three tabs at the bottom: the first tab has instructions, followed by a blank constraint form and a constraint log.

The application is designed to track constraints and to give the owner/general contractor (your client) notice that a constraint occurred, an explanation of what the constraint is, where it is and the impact the constraint may have unless resolved by a certain date.

How you use it is up to you. However, I highly recommend using something to track constraints because you never know when you might need to prove entitlement.


There seems to be a trend among many owners and general contractors that’s difficult for me to understand. The trend feels and looks like jobs run them rather than them running jobs. The owner’s biggest fears are cost overruns and not getting the project done on time. The general contractor’s biggest fears are their own cost overruns and not delivering the project on time.

During this fear fest, subcontractors can get overrun by cost impacts because subcontractors oftentimes want to keep their clients happy at any cost. Be aware that when a subcontractor doesn’t let someone else’s problems impact them or if they charge for the impacts caused by the owner or general contractor, the subcontractor is sometimes considered not cooperative.

For that reason, subcontractors are finding it very important to handle these issues in a polite manner and to pick their fights very carefully, because “we don’t want to alienate or lose the client” and that is how general contractors and owners make their problems your problems. It’s just another kind of constraint, no different than that person who is afraid of heights and won’t take that long elevator ride to the top of the Space Needle.

To download the “Constraint app” for free, visit www.wconline.com within the next 30 days.