The cost per square foot of adding an addition to your home can be more than actually building a new home per square foot. There are several reasons for this. One is because the contractor or architect has to attach the new addition to an existing structure. If this structure is not level or squared, then more calculations must be done in order to attach the addition. Second, there may be demolition to be done to the old structure in order to begin the new construction. Another reason is the addition must be built as an exact match to the standing structure. Finally, the contractor or architect must work around you and your family. This is usually not calculated in any estimate.

1. The primary cost of home additions are:
o Preparing and Design costs. You must have building permits which can be costly.
o Site preparations. Readying your home for the new additions, such as clearing the rooms that will be involved in the addition.
o Demolition – the removal of the debris. Large dumpsters are needed for this aspect.
o The Architect and Designer fees.
2. Construction costs. You will incur charges for both materials and labor for each of the following details:
o Heating & cooling. Running duct work for the air system.
o Electrical. Running conduit and electrical wires, plus having an inspector check the work.
o Plumbing. This is primarily for kitchens or bathrooms.
o Interior surfaces. Finishing walls.
o Exterior surfaces. Siding or brick to match the existing surface.
o Finishing the floor.
o Doors, windows and all trim.
o Cabinets, appliances and fixtures. This is primarily for kitchens or bathrooms.
o Framing.
o Cable, telephone service, internet or satellite.
3. Project management costs:
o General contractor, subcontractor and inspections.
4. Other construction costs:
o Insurance, losses, repairs, clean up, disposal fees, and sealing off other parts of the house. In addition to these, the do-it-yourselfer will incur charges for tool and safety equipment purchasing or rental.
5.        Hidden costs:
o         Taxes, insurance, utility bills, interior decorations, delays or problems, and late changes or upgrades to the existing project.

These costs are for your consideration. You can save yourself money by planning ahead. For preparation, try working with a contractor or home designer instead of hiring an architect, do your own demolition, prepare the site yourself, and seal off the area yourself. These can greatly decrease the cost of the project. To save on construction costs, do as much of the construction as you can possibly do yourself. Saving on hidden costs can be a real possibility as well. Simply sell or trade as much materials as possible from the demolition. Selling it will recoup your costs on some of your materials, and if you are able to trade it for materials you need, it will save on cost for materials.