Review architectural floor plans and elevations for the locations of various window types. Window schedules should be studied for the specific manufacturer, model, and size of the individual or combined unit. Occasionally, special details or sections through the unit may be used for clarification. The specifications should be studied for detailed information on the type of glazing, finish of the window, cladding color (if applicable), and accessories, such as screens or grilles. Acceptable manufacturers and required warranties are also listed in the specifications.
Taking off Quantities
Wood and plastic windows are taken off and priced by the individual unit or piece (EA). Quantities should be noted according to manufacturer, model or size, function (e.g., double-hung, casement, awning, or fixed sash), wall thickness, type of exterior finish, color of the finish, type of insulating glass, and exterior casing (for non-clad wood windows). Special options, such as grilles, screens, or blinds, can be taken off and priced separately or included as part of the actual window cost. For larger window units, such as bays or bows, many manufacturers offer the option of making normally fixed sashes operable, such as the center sashes in a four- or five-lite bow window. This often constitutes an additional cost, and should be noted in the takeoff for accurate pricing.
Many manufacturers fabricate windows to custom specifications, which can be expensive and require considerable lead times. To accurately price custom window fabrication, contact the manufacturer and obtain a direct quote, including any shipping costs. While most wood windows are manufactured for a normal wall thickness (2" x 4" construction), those constructed of thicker framing members (such as 2" x 6") require finish wood pieces to bring the jambs, head, and sill out flush to the interior finish surface. These are called extension jambs and are additional to the cost of the window.
Most wood and plastic window applications require two carpenters. For replacement windows set within an existing frame, the task can often be accomplished by an individual carpenter from the interior of the building. Labor costs are based on labor-hours per window or, alternately, the quantity of windows that can be installed by a crew in an eight-hour day. Consider staging or lifts for windows above the first floor.
Excerpted from Builder’s Essentials: Estimating Building Costs for the Residential & Light Commercial Contractor, available through RSMeans