Building permits are documents issued by a city's planning department to oversee and approve any changes to structures. You must get a building permit if you plan on making home improvements yourself or with the help of a contractor, architect, or construction worker. Building permits ensure that you are in compliance with building codes that regulate the processes of demolition, renovation, installation, construction, augmentation, or other changes in the use of a building.
It's necessary to register for building permits when you are involved with property construction because the government regulates the safety and purpose of buildings. For example, someone may want to convert a home into a small veterinary office. Even if they weren't doing any major renovation, they'd need a building permit. It would change the designation from residential to commercial use, provided that the property is zoned for a business.
Building permits are not just pieces of paper, but rather several stages in the process of getting your construction "permitted." At first, you will submit plans, like blueprints, of what you intend to do. A city planner will approve the idea, and then you will be allowed to begin construction. After demolition and part-way through building, the city sends a contractor to sanction what you have done so far. When construction is complete, someone else will sign off to make the building legal, official, and open for use.
Let's consider some common home improvement projects to determine how major a project must be to warrant receiving building permits. Every city and county is different, but there are trends in what needs to be permitted. If you wanted to change your PVC plumbing to copper, add a bathroom to the master bedroom, pave a driveway, convert a garage to a second dwelling, install another water heater, or rebuild your earthquake-damaged chimney, you will certainly need a building permit.
However, if you want to lay interlocking pavers for a backyard walkway, repaint wood siding, insulate your attic, add kitchen cabinets, erect a short fence, or put in a water filter, you probably won't need building permits for such projects. This is because these projects aren't significantly changing the structure or use of your building, and they have a low chance of precipitating unsafe conditions.
The inspections conducted by a city employee will evaluate several aspects of building permits. The contractor will check that you are following regulations such as the height of fences, the number of people living on a property, or the space between a structure and the property line. He or she may also suggest ways that you can update your property to "bring you up to code," such as adding another electrical outlet on a wall.