TYPES OF STAIR CONSTRUCTION.
Taking up the various details of construc tion, the housed string stair, one of the simplest and at the same time an important type, pre sents itself. This class of stairs may be divided into two kinds—first, where the stair is between walls (that is, where both strings are fastened to and supported by the walls); and second, where only one of the strings is fastened to the wall, and the other (the face or outside string) is free.
The first is the cheaper, and is used very much in small cottages, and also as a rear stair in the better grade of houses. Of course, very often both of these stairs are framed without the housed string. The treads are carried on a rough string, and the finished string is fast ened to the treads and risers by nailing through it into the treads and risers; but this is very poor construction.
By the term housed string is meant a string notched out to receive the ends of the treads Fig. 73. Housed-String Stair Construction.
and risers. An examination of Fig. 73 will show clearly what is meant.
In the stair between two walls, rough strings are unnecessary, unless the stair is over 2 feet 6 inches wide, when a rough string must be pro vided under the middle of the stair. The fin ished strings are fastened to the walls, and are more rigid than if a rough string were the means of support.
I Laying Out Stair Strings. After determin ing the tread and riser lengths, proceed to lay out the string. A little device very helpful in laying out a string is a gauge-board, as shown in Fig. 74, upon which has been cut the proper length of tread and riser to the pitch of the stair. In notching out the treads and risers, the notches should be cut large enough to receive a small wedge below the tread and back of the riser. These are used to make a tight Fig. 74. Use of Gauge-Board.
fit in front, where the treads and risers come against the edge of the notches. When the stairs are put together, the wedges are covered with glue before being driven into place.
Another method of laying out housing for stair strings is as follows: Joint top edge of string-board straight; draw a gauge-line down the required distance for the center of nosings. Then, having found the rise and run of riser and step, set dividers from rise on blade of square, and step off on gauge line the required number of treads. Next take a center bit the size of nosings, and start holes at these points. Next mark a pitch-board, as shown in the lower part of Fig. 75, at D, and a wedge-shaped stick F, the thickness of tread, plus the shape of wedge to be used in gluing up the stairs. Now place pitch-board on string, as shown at D in the upper part of Fig. 75, Fig. 75. Method of Laying Out Stair Strings.
and slide it along edge of string-board until edge touches hole E. Mark tread and riser; and, before moving pitch-board, place the wedge stick as shown at F and at dotted lines, and mark outside. Proceed to next tread in same manner, and so on. The projection of nosing may be regulated by making pitch-board longer or shorter on line B-C; but do not change the pitch.
Closed-String Stairs. A closed-string or box stair—that is, one between two walls—is built up against one of the walls before the second wall is built, which, when the stair is in place, is set up against it, and the string nearest to this wall is then fastened to the studding. If the stair is put in and lathing done afterwards, pieces of inch stuff will have to be cut between the studding along the string to receive the ends of the lath. A better way is to lath wall No. 1 before building the stair; V then put in the stair; and when placing the studding of wall No. 2, leave the thickness of a lath between the studs and the near string. Then lath this wall, shoving the lath through behind the string and nailing them below and above the stair. When this is done, the string may be fastened to the studding by nailing through the string beneath the treads and risers.