Estimate two to four labor hours per square foot. The exact time will depend on crew experience and the complexity of the house design. Your best bet is to pay your builder a fixed amount for the project, rather than by the hour.
Figure the costs for any leveling and excavation needed, such as for the foundation, septic system and utility canals. Add the cost for tree and stump removal, and the cost to bring in electricity, phone and water.
Include the delivery cost as well as the material cost per cubic yard for the concrete. If using block or brick, the cost is based on the unit, so you must know the size of the block to determine how many you will use; include the cost of the mortar, also. For foundation forms, figure in the cost to rent prefab forms or to buy lumber, plywood and nails to make your own. You'll also need anchor bolts, wall ties and reinforcing bars (rebar). The costs of waterproofing include asphalt, felt, drain tile and gravel. Add the cost of insulation if you will be insulating under the slab.
Floors and Stairs
Calculate the linear feet of the material being used for the sill, joists, beams, cross-bridges and girders. You'll also need to know how many square feet of plywood you'll use. Additionally, there are costs for termite shields, sill sealer, bolt nuts, nails and any connectors or hangers required. If your stairs are not prefabricated, you need to calculate the linear feet of stringer, tread, riser, handrail, newels and balusters.
For wood walls, calculate the linear feet of studs, headers and plates. Calculate the square feet of sheathing, insulation, vapor barrier and house wrap. Finally, add in the nails. If you're using masonry, you need to know the number of bricks or blocks, the amount of mortar and rebar, and the square feet of insulation and vapor barrier. If the masonry will face stud walls, you will also need metal ties.
Roof and "Closing In"
For roofs, you need to know: the linear feet of rafters, beams, girders and flashing; the square feet of sheathing, insulation, underlayment and vapor barrier; and how many pounds of galvanized nails you will use. "Closing In" includes the cost of windows, doors, door hardware and skylights. It also includes the cost of the fascia and soffit, siding and finish roofing--the shingles, ridge cap, drip edge and gutters.
Fireplace and Chimney
Adjust the costs according to the amount and type of brick or block--regular brick, facing brick and fire brick. Also consider the costs for mortar and concrete for the base, rebar and plywood forms. Smaller items include the ash pit, flue lining, metal shields, damper, lintel, grout, flashing and caulking.
You need to know: the length and material for the drain, vent, waste and supply pipes and the number of fittings, valves, drains, pipe hangers and faucets. Add in costs for the fixtures: the sinks, bathtubs, showers and toilets. Finally, add the bigger items: the septic tank, distribution box, drain tile, water heater and well pump.
Heating and Electrical Systems
Heating costs includes those of the boiler or furnace, pipes or ductwork, thermostats, registers, grills and baseboard units. For electricity, estimate the length and types of cable you need. Count the number and type of outlets and outlet boxes, switches and switch boxes, junction boxes and lighting units. Include the service panel, subpanels and circuit breakers.
Interior finishes include drywall, wood flooring, carpet, tile, paint, primer and wallpaper. Along with these, you must figure the amount of joint compound, nails, screws, joint tape, nailing strips, grout and adhesive you will use. Also include the length and type of moldings and baseboards. Finally, add in the cost of your kitchen and bath cabinetry, vanities and mirrors.
Permits and Financing
You must pay for a title search and title insurance, as well as all necessary permits. The cost of permits be a percentage of your estimated construction cost, or it may be based on the size of the house.
- Photo Credit Flickr.com/John Shappell
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