Martina Inc. has two service departments (Human Resources and Building Mainten

Martina Inc. has two service departments (Human Resources and Building Maintenance) and two production departments (Machining and Assembly). The
company allocates Building Maintenance cost on the basis of square footage and believes that Building Maintenance provides more service than Human
Resources. The square footage occupied by each department follows.

Human Resources 6000

Building Maintenance 13000

Machining 18000

Assembly 26000

Assuming use of the step-down method over how many square feet would the Building Maintenance cost be allocated (i.e. spread)?