Methods Of Estimating. Building costs may be divided into two main divisions, cost of material and cost of labor. There is but one so-called safe way to figure or estimate the cost of any particular piece of carpentry work. This consists in "taking off" the material quantities in detail and to this adding the labor cost of placing the same. This is the method in common use by contractors in making a final estimate. Where a rough or working estimate is required, such as an architect's estimate of the probable cost of a building planned by him, two methods may be used. One consists in figuring the cubical contents in feet and multiplying a predetermined, or unit price per cubic foot for that type of house. Ordinarily, the main frame is figured, counting from the basement floor to the top of the attic walls that are, or may be finished - outside measurements. Porches and open spaces are not figured. A second method consists in estimating the number of squares (100 sq. ft.) of side wall, of partitions, of floors, etc., and multiplying a predetermined price per square for a similar type of building. This latter method is more accurate than the cubic-foot unit method.