Estimating construction costs of a residence is a two step procedure for the contractor. The first step involves preparing a preliminary cost estimate on the total building project for the owner or architect. This will include approximate costs of the work to be done by all of the subcontract trades. The contractor should be able to estimate these without obtaining actual prices from subcontractors. The second step- checking costs with all of the trades involved- should be taken when the contractor is ready to prepare a firm, lump-sum bid for the project. Prior to getting each subcontractor's price, the contractor should know the worth of the work to be done. In preparing an estimate, it is recommended that you follow the specifications, item for item, giving page and paragraph reference and citing the title of each subtrade. Prepared forms are also available listing virtually all of the trades required for residence construction would include the following items. (1) Site clearing- this category includes the removal of any structures on the property. (2) Earth work- in this category are machine excavation, backfill and sand fill but not hand excavation. (3) Dewatering- the procedure of keeping the excavation dry while the concrete work is being done is another item the general contractor must take into account. (4) Concrete- concrete work for residences consists mainly of foundation walls, the basement slab on ground, basement stairs and exterior sidewalks, and possibly paving. (5) Waterproofing- waterproofing of foundation walls generally consists of a coat of cold-sprayed bitumastic damp-proofing. (6) Masonry- masonry includes the exterior face brick and the concrete block back-up work for it, along with such items as stone sills and any other work of this type. (7) Structural steel- this category is comprised of all the structural steel framing, including steel beams, miscellaneous lintels and steel joists and their setting. (8) Ornamental iron- ornamental iron includes wrought iron handrails for interior stairs, wrought iron grillage around porches and trellises, and other decorative iron work. (9) Wood stairs- here we are concerned only with finished hardwood stairs such as those leading from the first floor to the second floor and not those going to the basement. (10) Carpentry- Carpentry is the catch-all category for everything that is not covered elsewhere. (11) Millwork material. (12) Wood roof trusses. (13) Insulation- this is the blanket insulation that goes into the wall framing or is betwen the studs. (14) Finished hardware- this item includes the hardware for doors, windows, and cabinet work. (15) Metal windows. And (16) Hollow metal door frames.