Identification

• Stair stringers form the structural support of a basic staircase. Two sloped pieces of wood, extended from one floor level to the next, create the backbone on which the steps and risers rest. A contractor may at times choose to add a third stair stringer for added support, which would run down the center of the staircase, in between the other two.
  
  

Types

• There are two types of stair stringers. Looking at a staircase head on, the 'open string' appears to be suspended between the two floors, unobstructed. The stair strings are openly visible on both sides, with no walls on either side, only banisters and rungs. The second type is the 'closed stringer' which is attached to the wall. In this type, only one side of the staircase is attached to a wall, with the other side harboring a banister and rungs or in some cases such as, basement stairs, both sides may be attached to running walls.
  
  

Size

• It is recommended when building a staircase that each step is no less than 36 inches wide, with a depth of at least 12 inches. The risers also have a recommendation, which is at least 8 inches in height. When building stair stringers, it is important to take this information into account. And in deciding the length of each stringer, the vertical distance of the proposed staircase must be measured, and divided by 8 (remember: the riser heights will be 8 inches each). Round your quotient to the next whole number, which will in turn, give you the amount of steps that will be necessary to build the staircase. For instance, if you measure a vertical distance of 144 inches, divide that figure by 8, your answer will be 18 steps (144 ÷ 8= 18).
  
  

Considerations

• The strength of your staircase needs to be considered when choosing the wood to build it. A contractor will normally opt between 2 by 10 and 2 by 12 foot lumber pieces, With the 2 by 10 being the most supportive, and preferred, when an open string staircase is being built. The extra 2 inches of support may not seem like a big difference, but it can be of tremendous benefit if the staircase will also need to support the weight of a heavier person.
  
  

Warning

• A durable staircase requires woods that can hold up against a daily barrage of weight and foot traffic. Choosing a high quality wood is important, and viewing the wood before purchasing is a necessity. Wood that will be used for stair stringers must be free of any bowing or warping. For aesthetic purposes, wood that is free of large knots is also preferred.
  
  

Expert Insight

• If you are not comfortable making your own stair stringers, prefabricated ones are available. Companies manufacture ready made stair stringers in a variety of wood styles as well as, cost effective metal types that are easy for the do-it-yourselfer to install.