In managerial accounting you learn how to calculate the cost of goods manufactured, which includes direct material, direct labor, and manufacturing overhead costs. Direct material and direct labor can be calculated easily. Overhead, on the other hand, is difficult to measure accurately on a project by project basis. A refresher on manufacturing overhead is provided below.
GAAP says that overhead costs related to self-constructed assets should be pooled with manufacturing overhead costs and allocated to self-constructed assets based on the relative amount of the cost driver used. GAAP calls this the full-cost approach.
GAAP says interest can be capitalized for:
Assets built for the company's own use, or
Assets constructed as discrete projects (e.g., a ship or a real estate development).
GAAP says capitalization can begin when construction begins and the first construction expenditure has been made as long as interest costs have actually been incurred.
Answer: No. The only requirement is that the company have some outstanding debt. The assumption being made is that, even if a loan isn't taken specifically for the construction project, the funds used for the construction project could have been used to payoff existing debt. Therefore, the new project used borrowed funds indirectly.
In the example above, the calculation would use a weighted average interest rate - calculated using all outstanding loans - in place of the 8% rate. The weighted average rate would be calculated as follows.