Stair Building Simplified

Fig. 71. Layout of Simple Stairs.

Lay out the stairs first, allowing ample space; and plan the rooms accordingly. Fig. 71 shows a straight run of stairs which may be taken as typical; it is the simplest of any to build. From the starting point to the level of the floor above, is 10 feet 3 inches, or 123 inches; and as there are 17 risers, there would be 7 inches to each rise. Now, as there are one less of the treads than there are risers, multiply 16, in this case, by the desired width of the tread inches), and we obtain 152 inches, or 12 feet 8 inches, for the rim of the stairs.

The next thing to consider is the proper length of opening to leave in the second floor, so as not only to give ample head room for the more than average tall person, but also a gen erous allowance for the free passage of furni ture, trunks, etc. It is best to give plenty of room. The head room should be at least a little higher than usually given to the room doors, say 7 feet 6 inches or 8 feet. Plenty of room should be allowed in the framing, as it is an easy matter to fur out the trimmer if it is afterwards found desirable to reduce the space. The length of the opening can be found by deducting the amount of the number of risers from the room height that will leave ample head room. In this example, if we deduct the height of two risers, which is practically 1 foot inches, from 9 feet 1/2 inch, 7 feet 10 inches is left above the second riser. It is safe, then, to place the trimmer above, a little farther forward, as shown in the illustration. It must be remem bered that when the well-hole is lathed and plastered, it reduces the height accordingly.

Many workmen prefer to use a pole on which they mark the heights from floor to floor and then divide this into the number of equal spaces that there are to be risers. The pole can also be used to advantage where the total run is desired to come inside a given space, as it obviates the necessity of a mathematical prob lem that usually runs into fractions.

For general use, however, in calculating the Fig. 72. Table Giving Number of Treads or Risers of Any Width for Any Size Space.

layout for stairs, the accompanying table, Fig. 72, will be found very handy and useful as a time-saver. The first row of figures running down the left-hand side, represents the number of risers, while the first row running across the top represents either the rise or the width of the tread. Those in the following lines repre

sent either the total rise or run for the number of risers shown in the opposite left-hand column.

For example: Suppose we wish to find the number of risers required in a stairway that is 10 feet inches from floor to floor, and we desire to keep the risers as near inches as possible.

Operation—Take in the top line, and run down the column to the nearest figures to 10 feet inches. It is 10 feet inches, and is opposite 17 in the left-hand column. There fore, 17 represents the number of risers; but there is 2 inches left over. This must be divided into 17 parts and one of these parts subtracted from each riser, which would be nearly inch less than inches.

Now look in the next column to the left. In this, the risers are inches; and for 17 risers, the total is found to be 10 feet inches, which is just inch short. Thus the risers will be inches, plus of 1/s inch.

To find the run of the stairs, it must be remembered that there is always one less tread than there are risers. So take 16 in the left hand column, and trace the figures to the right till you come to the column whose figures at the top represent the desired width of tread. Sup pose it to be 9 inches, then it will be found that the run will be 12 feet. If the treads are inches wide, then the run will be 12 feet 8 inches, and so on for any desired width of tread. Usually there is some leeway in the run; that is, it is not confined to a certain space like the rise from floor to floor. Therefore, a few inches in the run of a straight flight of stairs does not usually make any difference, thus leaving it to the builder to select at once the width of tread desired. When this cannot be done, then the allotted space must be arrived at in the same manner as that given in the above for the risers. But after all, it should be remembered that while the measurements can be accurately found by the aid of this table, its greatest utility is as a quick reckoner, in laying out the space and proper openings for the finished stair work. In that case it is not necessary to calculate down to the minuteness required in the building of the stairs.