A builder specializes in moving homes from one site to another in the Midwest after the land that the home currently resides on was sold to an airport. The builder has asked for your help in determining how to schedule the project of rebuilding a home at the lowest total cost. This home is a one-story ranch home (about 2,000 square feet) that is located in a small suburban town.

The homeowner wants the home built in 60 days. The owner will charge you a penalty cost of $100 per day if it is not completed on time. The builder’s weekly overhead cost at a site is $350 per day. The following table relates information about the activities necessary for building the home.

The crash cost and time differ from the normal cost and time due to the need to pay the subcontractor a bonus or overtime for finishing an activity quickly. This information can be used to determine which activity (if any) to crash and the amount of time to crash it. The crash time is the minimum time needed for that activity. However, an activity can be crashed to a time between the normal and crash times. For example, you could crash Activity F for one day only at a cost of $600, or two days for $1200.

1. What is the critical path? Can this project be completed on time using the normal activity times?

2. Which activities can currently be delayed without delaying the entire project? What are their corresponding slack times?

3. Decide how many weeks it will take to crash the project and explain how you would crash it. What is the net savings from crashing the project?

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Activity Description ABCDE F G H I J K L OZN M Prepare land Obtain building permit Dig for footers and inspect Foundation Block inspection Framing, roofboards, and wallboards Roof shingling Windows and all doors Rough in plumbing, electric, heat and air conditioning Insulation Inspection of electric, etc. Sheet rock, texture ceilings Interior painting Install tub, sinks, and toilets Install cabinets, doors, and Immediate Predecessor s) None None A,B D E F G H I I J, K L M M Normal Time 1 10 2 3 1 10 2 2 9 3 1 a7 9 2 2 Cost 1,800 200 1,000 6,000 0 37,200 3,500 7,200 3,700 3,700 0 Crash Time Cost 1 10 2 3 1 7 1 1 6 2 1 9,600 7 2,700 1 2,800 1 12,000 5 1,800 200 1,000 6,000 0 39,000 4,000 7,625 4,000 4,000 0 10,500 3,200 3,000 12,750