This section is from the book "A Treatise On Architecture And Building Construction Vol4: Plumbing And Gas-Fitting, Heating And Ventilation, Painting And Decorating, Estimating And Calculating Quantities", by The Colliery Engineer Co. Also available from Amazon: A Treatise On Architecture And Building Construction.
48. Hardware is best estimated by noting the quantities required for each portion of the work as it is being measured, afterwards making these items into a separate hardware bill. Many of the articles, as, for example, the number of fixtures for doors or window trimmings, may be readily counted from the plans.
Hardware for windows, doors, etc. are sometimes included in estimating the cost per window, door, etc., and are not considered separately. In the estimates of such costs under "Joinery" (Arts. 43, 44, and 45), this method is followed; while in the complete example of estimating, given hereafter, the hardware is made into a separate bill.
The cost of the hardware depends entirely on the class of work and finish desired, and the best way to estimate on it is, after making the schedule, to select suitable designs and figure the prices from a catalogue.
An approximate estimate for the hardware in ordinary buildings is 1 1/2 per cent. of the cost of the building. From 15 to 20 per cent. of the cost of hardware will pay for putting it in place.