Humphries construction company builds warehouses that range in size from 12,000 to 100,000 square feet. which of the following would not be a rational base for allocating overhead costs to the warehouses?
square footage of the warehouses
labor hours
direct material costs
number of warehouses completed

The Number of warehouses completed would not be a rational base for allocating overhead costs to the warehouses.

Explanation:

For allocating the overhead cost to the warehouse. Following things need to be considered.

1. Square footage of the warehouses : Based on the square foot of the warehouse, the overhead cost can be easily allocated. As different warehouses have different square foot. So there would be different allocation criteria for each warehouse.

2. Labor Hours : According to the labor hours, the overhead expense can be allocated. In warehouse, the size of labor is matter. As more labors are available, the chances of more allocation expenses would be there and if there is less labors so the allocation expenses would be less.  

Depending upon the size of the labors, the allocation of overhead differs.

3. Direct material cost : The warehouse is required when more supplies of material is to be required. So here, direct material plays an very important role while allocating the overhead cost. Depending upon the quantity of  material, the overhead expenses differs.

4. Number of warehouses completed : As without knowing the size and capacity of the warehouses, it is difficult to allocate the overhead expense. Moreover, the same cost is been allocated which is not acceptable.

Hence, the Number of warehouses completed would not be a rational base for allocating overhead costs to the warehouses.