Distance Between Stringers in Wrap Stairs

Determine the shape of the deck and the wrap-around stairs. The stringers basically extend out from the corners of the deck by cutting the joint angles in half. So if the deck has a square or a rectangular shape, the joint angles are 90 degrees and stringer angle should be 45 degrees. If the deck corners are at 45 degrees, the stringer angles should be at 22.5 degrees.

Hammer a nail into the front of the joist where the staircase will begin. Wrap a string around the nail and allow it to hang down. This is the rise of the staircase and is used to calculate the number of steps.

Choose the height for your steps. Most steps are 6 to 7 inches tall. All the steps of your wrap-around stairs should be of the same height to avoid accidents. Once you choose the step height, divide the rise of the stairs with the step height. This will give you the number of steps. If the result of your division is not a whole number, adjust the height until you get a whole number.

Measure the horizontal length of the stairs and divide the number with the horizontal depth of steps to determine the straight stringers. Wrap-around stairs also require the treads for the corner stringers. Use the Pythagoras theorem to determine this value. The formula is: A(2) + B(2) = C(2). For example, if the straight stringers have a tread of 10 inches, enter the value instead of A and B such that: 10(2) + 10(2) ... and 100 + 100 = 200. Now take the square root of 200, which is 14.14 approximately. Round this value to the nearest whole number to determine the treads of the corner stringers. Use the calculations to build your wrap-around steps.