In estimating the cost of a building, there is no accurate rule or method that can be given. The common method is to obtain the cubic contents of a building and by estimating the cost of the construction of each particular class of building at so much per cubic foot, decide the total cost in this manner. It may be readily seen that the variation in cost of buildings of the same general character and construction may be so great as to make this method inadequate and inaccurate, but for the purpose of estimating the cost of improved property, it is the only available method. This cost should not be considered as the true index of value, but the other points enumerated should be carefully considered.