Construction projects that have a mixture of union and non-union trades are becoming more prevalent. A contractor undertaking a mixed-trade project must understand that harmonizing these two groups may present challenging issues. (This article does not address area-wide strikes, only strikes specific to a single, mixed-trade project.)

As with many problems, those involving labor harmony often begin with the owner-contractor agreement. Owners are increasingly insisting on labor-harmony provisions that obligate the contractor to staff the job despite the occurrence of picketing activity and prohibit the contractor from obtaining extra time or money for delay or disruption occurring as a result of picketing activity. Therefore, contractors must understand their risks and know how to manage a mixed-trade project in order to minimize the risk of delay and disruption.
If the owner is responsible for supplying the nonunion labor, the contractor may want to consider negotiating the prime contract for entitlement to time and cost increases in the event of a picketing delay or disruption. However, if the contractor hires the nonunion labor, the owner will likely expect the contractor to bear the risk of time and cost impacts due to delay or disruption as a result of picketing activity.