There are particular trade partners that are on board with playing catch up. They will help you make up days if possible.
Recognize that and make it worth their while. A drywall hanging crew that works through the weekend to make-up two lost days and ensure you don't have to reschedule your trim package, paint and cabinets may have saved you many hundreds of dollars. A crisp 50.00 bonus may be in order.
Sometimes getting the crew pizza's and soda is enough to motivate a few extra hours of work. Let them know you appreciate the extra effort.
This is one unfortunate thing the owner builder may have to do. Firing a trade contractor for non-performance is never a pleasant task. Sometimes, however, there is a contractor that will not complete their work. They will make excuses and break promises.
Tomorrow, tomorrow, Monday, first thing tomorrow, turns into... My truck broke down, my kid got sick, my wife got sick, I got caught up at another job, back into tomorrow, tomorrow...This has a devastating effect on construction scheduling.
Bottom line, the owner builder's success is not important to this person. If he has not done the initial work, the subcontractor should be fired. There are other contractors. If the initial work is done but the original trade contractor won't complete the pick-up tasks, an owner builder may hire a licensed hourly tradesman to finish the work.
The cost can be covered by the subcontractor that did not finish the work through a back charge. A well written subcontractor agreement, will prevent most disputes. Contact and reschedule trades and suppliers. Identify those that will help you make-up lost days and keep them informed of progress.
Construction Scheduling and Management Software
Scheduling is a function of owner builder construction management. There are a number of construction scheduling programs available.
Some software is even designed specifically with small companies and owner builders in mind. They all are fairly pricey but may be just what you need to keep your project organized and on schedule.