I have taken the following from Ellis' Practical Treatise on Joiner's Work, because it seems to me to be about the best thing written on the subject, at least, the, best I have come across. "The amount of going and rise given depends chiefly upon the amount; of floor space allotted to them, and upon the height of the story; but subject to these restrictions, there is room for considerable variation. To obtain a stair that shall not be fatiguing or awkward to ascend or descend, the going should bear a certain ratio to the rise. Various methods have been proposed by writers on the subject to obtain the ratio, of which the following are the best known and most practiced:
"1. It is assumed that the average length of stair parts step in walking on the level is 24 in., and that it is twice as difficult or fatiguing to climb upward as it is to walk forward. From these premises it is deduced that one going one step forward, plus two rises or steps upward, should equal 24 in., which put in the form of a rule becomes,
"To Find the Rise When the Going Is Known. -Subtract the given going from 24 in., and divide the remainder by 2 for the rise.
"To Find the Going When the Rise Is Known.-Multiply the given stair parts rise by 2, and subtract the product from 24. The remainder is the proportionate going required.
"2. The product of the going and rise multiplied together is to equal 66. Example: Going 11 in. x 6 in. = 66, and 7 in. rise x 9 3/7 in. = 66. Rule by this method: Divide 66 by the given rise or going to ascertain the proportionate going or rise.
"3. Assume 12 in. going and 5½ in. rise as a standard ratio. To find any other, for each addition of / in. to the rise, subtract I in. from the going. Example: Stair Parts Rise 6 in., going II in.; rise 7 in., going 9 in. It will be noted that by this method the sum of 2 rises plus the going equals 23, which affords an easier stair than the first-mentioned method.
Stair Parts Fig 32
"When the total rise of the stair is known, as shown by the story rod, Stair Parts Fig. 32, and the approximate rise of the step is given, the exact rise is obtained by calculation, thus: Reduce the total height to inches, and divide it by the desired rise. If there is no remainder, the divisor will be exact rise, and the quotient will be the number of risers required. If there is a remainder, again divide the sum by the quotient, discarding the fraction, and -the result will be the exact rise. For instance, let - the height of the story be to ft. 6 in., and the proposed riser 6 ½ in. to ft. 6 in. = 126 in. = 6 ½ in. = 19 with 5 remainder; then 126 in. = 19 = 6 ⅝ in. full as the rise, and the proper ratio of going to this, as found by the first method, is 6 ⅝ x 2 = I3 ¾ - 24 = I0 ¾; but the exact going is found by dividing the plan into 18 equal parts, as there is always one less tread than the number of users, in consequence of the landing acting as tread for the last riser. No arbitrary rule can be given for the treatment of the plan, which must be subject to circumstances. Every attempt should be made, however, to dispense with winders, which should be introduced in case of necessity, when they are better placed at the top of a flight than at the bottom."
All stairs should be so devised that not less than 6 ft. 6 in., head-room between tread and trimmer, is given, but, as shown in Stair Parts Fig. 32, it is much better to give this much space from the going line to the trimmer, then
Stair Parts Fig 33
there will be no danger of a tall man striking the trimmer with his hat on his head. There will be cases, of course, where to give so much space for head-room will be impossible, but in ordinary stairways any less space than that determined will surely prove unsatisfactory.
Various Plans For Stairs And Stair Parts Use
A stair parts newel or landing stair can be devised that it will serve the purpose for almost any possible contingency; and in order to make this plain I show a number of plans, which I am sure will prove of use to the general workman as well as to the stair-builder, as they offer hints and suggestions for dealing with almost every, condition and situation that are likely to present themselves in preparing stair parts plans for stair runs which are intended to be of the platform style.
In Stair Parts Fig. 53, I showed a plan of a stair having two landings, and a circular-ended step, with dotted lines showing trimmer timbers. At Stair Parts Fig. 34, I show another plan with the order of going reversed, and with the flight between the landings having a less number of steps. Stair Parts Fig. 34 only shows five risers, while Stair Parts Fig. 33 shows nine risers. The latter example also shows the two lower steps rounded off to fit against the newel post. The flight shown in Stair Parts Fig. 34 is supposed to be built in between studded partitions while the stairs shown in Stair Parts Fig. 33 are built in between brick walls.
Stair Parts Fig 34
Stair Parts Fig 35
Stair Parts Fig 36
Stair PartsFig. 34 shows a plan of stair in the Time St. Depot, Liverpool, England. This is rather a peculiar stairway, as from the third landing the stair starts off in two directions so as to reach different parts of the building. more conveniently. The plan shown at Stair Parts Fig. 35 illustrates an elaborate entrance and stairway to the National Gallery of Arts, London. This is a peculiar stairway inasmuch as there are two flights leading up to a large platform where the upper flights broaden out and carry the visitor to the upper floor either to the right or to the left. This is rather an ingenious arrange merit and might be made use of in many instances for public buildings.
An effective arrangement for a hall stair is shown at Stair Parts Fig. 36, where a short flight of stairs lead to a raised dais from which a second flight of stair springs, in which there are two landings. The rail over the lower flight runs from two starting stair parts newels, and finishes against columns having their base on the plinth of the dais. The windows in the rear of the hall are filled with art glass, and the whole is artistic and impressive.