Prioritize your desires for the new space. One way to do this is to determine what problems you have or what areas need improvement. The answers to these questions should influence the design of your addition. Consider furniture placement, traffic flow and special electrical or storage needs as you prioritize.
Educate yourself about the restrictions associated with building projects in your city or county. There could be height limitations, setback restrictions (how close you may build to your property line) or land-to-building ratios that must be honored. Investigate any neighborhood or historic preservation codes that might be relevant to your project.
Estimate the cost of your addition. To do this, calculate the approximate square footage that you want to build. Call several contractors to get an average rate per square foot for your area. Many factors affect the overall cost of an addition. Kitchen and bathroom projects are usually more costly than bedrooms, for example.
Decide whether to hire a contractor or be a contractor yourself. If you do it yourself, you should still expect to hire an outside contractor for some portion of the project. Building codes differ from place to place; electrical wiring or gas lines may have to be professionally installed in your area.
Draw up a working plan. Hire a designer, draftsman or architect to accomplish this task if you are not qualified to do it. This plan will be needed to acquire the building permit and get a loan. A professional can help with the seamless layout of the design and function of the addition.
Call for the location of underground water, electrical, telephone and septic lines before breaking ground.
Select the building materials. It can be difficult and sometimes impossible to find the materials that match your home. Be prepared to make changes.
Order the materials once you have selected them.