According to the Home Safety Council, a national nonprofit organization dedicated to the prevention of home-related injuries, 20,000 deaths and 21 million medical visits can be attributed to home-related injuries every year. Of this number nearly one-third are the result of falls, and stairs are the second leading cause of death due to falls.

There are many components in a stairway that are safety-related, including the dimensions of the steps and the design and stability of railings. Building codes in Georgia are very specific on the design and construction of these components. The following is a primer on safe, code-compliant stairs and landings. How do your stairs match up?

Kimberly Smith/AJC (ENLARGE)

Handrails must be provided on at least one side of any flight of stairs with four or more risers.

Charlotte B. Teagle/AJC (ENLARGE)

To ensure safety, building codes for stairways cover individual stair heights and the limited variance allowed among those heights; the depth of stair treads; handrails; and lighting. Stairs in homes built in earlier eras may not conform to all of today's code requirements.

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1. Treads and risers: For beginners, treads are the part of the step that you actually step on and the riser is the vertical height of the step. According to the currently adopted residential building code, the 2006 International Residential Code, the minimum depth of a tread is 9 inches and the maximum riser height is 7 3/4 inches. In the attempt to prevent tripping, the height of risers cannot vary by more than three-eighths of an inch in any flight of stairs. The exception to this rule is the bottom and top steps, which can vary in height by three-fourths of an inch. In some historical buildings in the South, this rule was purposely ignored in the hope of tripping burglars.

2. Handrails: Handrails must be provided on at least one side of any flight of stairs with four or more risers. The handrail must be continuous the entire length of the stairs, except at turns, and the top of the rail must be a size and dimension that can be gripped (a 2x4 does not meet the standard). The handrail must also have a minimum height above the tread of 34 inches and a maximum height of 38 inches.

3. Lighting: Stairways must be provided with artificial light. The light must be bright enough to illuminate the entire stairway, and for interior stairways, be located in the immediate vicinity of the stair landings. In stairways with six or more risers, there must be a switch for the lights at each floor level.

4. Guards: In code book terminology, guards are those railings that surround porches, balconies, ramps or other raised floor surfaces. This includes the top surface of exterior retaining walls. Guards are required when the raised surface is 30 inches or higher above the surface below. Guard rails must be a minimum of 36 inches high. The spaces in the railings must be less than 4 inches for flat raised surfaces and less than 4 3/8 inches for railings on the open sides of stairs. One other exception allows the space between the bottom horizontal stair rail and the triangle formed by a tread and riser to be less than 6 inches.

5. Stair dimensions: All stairways are required to be 3 feet wide. The handrails are allowed to protrude 41/2 inches into this three-foot space. Since the rails can be on both sides of the stairs, the actual width of the stairs can be reduced by 9 inches. The ceiling height of the stairway must be a minimum of 6 feet, 8 inches. For simplicity, this height should be measured from the front edge of a tread.

6. Rail stability: All guardrails and handrails should be constructed to withstand a single concentrated load at any one point along the top of the railing of 200 pounds per square foot. The infill components in the railing must be able to withstand a 50-pound-per-square-foot load applied to a 1-square-foot area.

Please remember that the above rules are basic. There are a number of other requirements for safe stair and raised-surface construction that exceed the parameters of this article. It should also be kept in mind that codes are constantly changing, and these requirements cannot be applied to older houses without a thorough understanding of what codes were in effect at the time the house was constructed. However, if your home's stairs and raised floor surfaces meet or exceed the above requirements you can feel good about your safety.

Do you have a home repair question? Send e-mail to Ask the Inspector at H&G@ajc.com. Our expert, Bill Garwood, spent 15 years as a building contractor before becoming a home inspector in 1990. He is part owner of a residential inspection firm and a company providing training in building inspection and codes.