183. While it is not necessary for an architect to be able to lay out the actual construction of a flight of stairs, or to tell just how the hand rail is to be worked, nevertheless he should be familiar with the general methods of constructing stairs, so that he can tell when they are properly built, and be able to plan the stairs in the buildings which he designs so that they may not only be ornamental, but also safe and comfortable. He should also be familiar with the various terms used in describing stairs, so that he can talk intelligently with the stair-builder and prepare a proper specification. The terms in general use amongst stair-builders are as follows : The term staircase is applied to the whole set of stairs, including the landings, etc., leading from one story to another, or if several stories are connected by flights of stairs one above another, the whole series of stairs is included in the term. A flight of stairs is the portion of a staircase from the floor to a landing, or from one landing to another, or, if there is no landing, from one floor to the next. The rise of a stair is the height from the top of one step to the top of the next. The run is the horizontal distance from the face of one riser to the face of the next.* The risers are the upright boards, R, Fig. 286. The treads are the horizontal boards T which form the steps. The nosing includes the projection of the treads beyond the riser and the small moulding placed in the angle. The carriages are the rough timbers which support the treads and risers. They are also sometimes called "strings" or "stringers." The wall string or base is the finished board placed against the wall corresponding with the base around the room. The outside string is the finished board on the outside edge of the stairs.
The newel is the main post where the stairs begin ; it is generally larger and more highly ornamented than the other posts. Angle posts are the posts used at the angles of a staircase or well. Winders are the steps which come in the angle of a flight of stairs, as W W, Figs. 290 and 292.
Laying Out. - In planning the stairs the architect must be governed to a great extent by the conditions imposed by the plan and arrangement of the building.
. The first point to be considered will be the number of risers to be used, and then the width of the treads and the general arrangement of the stairs. The rise of the stair should never be greater than 8 inches, and that only in inferior stairs. For grand staircases the rise is often made only 5 ˝ or 6 inches, but to the average American this height is nearly if not quite as tiresome as an 8-inch rise. For ordinary use a rise of from 7 to 7˝ inches makes a very comfortable stair. In schools and other buildings where the stairs are to be used largely by children the rise should be about 6 inches. The width of the run should be determined by the height of the rise ; the less the rise, the greater should be the run, and vice versa. A safe rule for this proportion is to make the sum of the rise and run equal to 17 or 17 ˝ inches.* Thus a 7-inch rise should have a 10 or 10˝inch run and a 7˝-inch rise a 9˝J or 10-inch run. The actual width of the tread will of course exceed the run by the projection of the nosing, which should be about 1˝ inches.
* The terms "rise " and "run" are often used to designate the total rise or run of the stairs and not of the individual step, but, as they are much more useful terms when used as here defined, they will hereinafter be used with these meanings.
The above rule applies only to steps with nosings. When there is no nosing, as is commonly the case with stone steps, the tread should be wider, seldom less than 12 inches.
The number of risers that will be required is determined by dividing the distance between the floor levels by the rise. It is seldom that the quotient will be without a fraction, and, as the risers should all be of the same height, it will be necessary to vary the assumed rise to conform to the number of risers adopted. Thus : supposing the distance between the top of the first and second floors of a building is 10 feet 9 inches and we wish to use a rise of about 7˝ inches.
This rise is contained in 10 feet 9 inches (129 inches) 171/5 times, so that we must use either 17 or 18 risers. The former would give a rise of 7 10/17 inches and the latter a rise of 7 1/6 inches. The run of the stair should be made either 10 or 10 ˝ inches.
In figuring the stairs on the plan the number of risers only should be given, leaving the stair-builder to work out the rise from the actual height taken from the building, as this is apt to vary slightly from the height figured on the plans.
Besides the number of risers, the run and the width of the stairs from the wall to the centre of the rail should also be figured. For inferior stairs the width may be as little as 2 feet 9 inches, but never less than this. For the principal stairs in moderate-priced dwellings a width of 3 feet does very well, but 3 feet 6 inches is much better.
Having decided upon the number of risers and the run, the next step will be to arrange the stairs so that the requisite number of steps may be provided in the space available for them. This is often a difficult problem and one requiring considerable experience in planning for its satisfactory solution.
* Another very good rule is that the product of the rise and run shall not be less than 70 nor more than 75. Still another rule, given the author by an experienced stair-builder, is that the sum of two risers and a tread shall be not less than 24 nor more than 25 inches.
The simplest and cheapest method of building the stairs is to have a straight run, as shown in plan. Fig. 287, the dotted line showing the rail around the landing on the floor above. This frequently requires a longer space than is available, so that it is often necessary, especially in dwellings, to turn the stairs either at right angles or back on themselves to get the requisite number of steps into the space at
For back stairways where the space is very limited the arrangement shown in Fig. 288 is generally adopted, as it occupies the minimum amount of space. If the rise does not exceed 7˝ inches this makes a comfortable stairway, but when the rise is 8 inches it becomes almost dangerous. Such stairs are very unhandy for carrying up furniture. Builders sometimes put four winders in the angles, as indicated by the dotted line ; such an arrangement, however, is really dangerous, and the architect should never use more than three winders (two risers) in a space less than 3 feet 6 inches square. Fig. 289 shows a very common arrangement both for front and back stairs. When there is sufficient space the winders should be omitted and the straight flights lengthened to correspond.
In cottages, where the front stairs are built in this way, a closet or room often occupies the space usually devoted to the stair-well. With
Fig.291 such a plan the partition should be set back so that there will be a space of at least 2 inches between the outside of the rail and the partition, as shown in the figure. If the partition comes directly over the rail it is impossible to make a good finish of the latter, and there is also danger of one's hitting his head when ascending the stairs.
Fig. 290 shows an improvement over the stair shown in Fig. 288, although it of course occupies more space. The arrangement shown in Fig. 290 is sometimes termed an "open newel" staircase, while the stairs in Fig. 288 are termed "dog-legged."
Fig. 291 shows a full platform, which makes the easiest stair that can be designed, and if the platform is made wide and fitted with a seat it makes a very ornamental feature. A staircase having a full platform is also much simpler of construction (i.e., if the landing can be supported by partitions) than one with winders, or even with two platforms, and is also much firmer.
The various arrangements of stairs that may be made for ornamental effect in dwellings is almost unlimited, but in most cases they will be found to be made up of one or more of the arrangements here shown.
Previous to 1850 it was the fashion in this country to build circular or geometrical stairs, such as are shown in Figs. 292 and 293, for the principal staircase in the better class of houses. The latter plan is now seldom used, as it is a costly stair to build and not as easy or effective as the platform stair, shown in Fig. 291.
When winders must be used the objection to them may be largely overcome by using round corners, as shown in Fig. 292. This makes the stairs much easier and also much more convenient for carrying up furniture. When it is necessary to use winders in public buildings they should wind around a circle of sufficient radius that the width of the treads at the narrow end shall be at least 4 inches, exclusive of the nosing.
Balanced or Dancing Steps. - Although winders are generally drawn as shown in Figs. 288-290, the stair-builder often builds them as shown in Fig. 295, the winders not radiating to the centre, but converging to different points, as also two or three steps on each side of the winders. This makes a much easier stair than the regular winders. The English term for steps arranged in this way is "balanced" or
"dance" steps ; there does not appear to be any term for this arrangement in common use among American stair-builders.
In geometrical stairs, such as those shown in Fig. 293, owing to the winding steps having the same rise as the others, but a much narrower tread at the inner end, the inclination of the line of nosings of the winders is much steeper than that of the other steps, which gives a sudden and ungraceful change to the inclination of the hand-rail. To avoid this and also to give some additional width at the narrow end of the tread the steps are "balanced," as shown in Fig. 294, each riser converging to a different point.