Stairs are the means by which ascent or descent is made from one level (or floor) to another. They can be made of stone, iron, concrete, or wood; but it is only intended to deal with wooden stairs in this chapter.
The stairs themselves are built up of a continuous range of light boards, grooved and tongued together, and arranged in horizontal steps rising one above the other in a raking line drawn from the bottom, or starting-point, to the top or place where it is required to land.
The ends of these boards or steps are connected to stouter boards, pitching from the bottom to the top to the raking line just alluded to; and they are often supported in the middle, as will be explained more fully hereinafter.
This structure of boards, etc., called stairs, connecting the different floors together, is enclosed in a staircase, which is either a specially built chamber, or a space or part of a larger apartment set aside for the purpose.
When the latter is the only provision made for containing the stairs, the floors and ceilings have to be trimmed, as Fig. 793, in order to provide headway, and allow of communication between the stairs and the higher floor levels, with which the stairs themselves are the means of communication.
It is needless to say that there are numerous kinds of wooden stairs, differing from each other in principle and in form, but alike in general detail, although the mouldings and mode of treatment may differ a little However, before entering into these details, or going into an explanation of the different kinds, it will be as well to acquaint the student with the meaning of the different terms and rules applied to stairs in general.
The tread is the flat horizontal surface of the step on which the foot is placed (distinguished by T on the illustration, Fig. 794).
The riser is the vertical face of the step, or the upright, R, which connects the back of the lower tread with the front of the upper one.
The nosing is the edge of the tread, which projects beyond the face of the riser; it is usually rounded, and sometimes, by means of a small hollow fillet planted underneath, it is made moulded (as shown in Fig. 794).
Newels (N) are the vertical posts, either square, moulded, or turned, which connect the handrails and strings of different flights together. The riser of the top or bottom steps is always housed into the centre of the newel at their various heights.
A stair generally starts with a newel where there is no wall to receive the ends of strings, handrails, etc., whether it be at the top or bottom, in each of which cases the newels are a convenience and an ornament.
The strings (S T) are the "walls" of the treads and risers of the stairs. Each step is housed into the strings at both its ends, the string running from newel to newel, or from floor to floor at the inclination of the stairs, and parallel to the line of nosings and the handrail.
The handrail (H) is a rounded or moulded rail, fixed above and parallel to the string along the walls, or from newel to newel, for the convenience and aid of persons using the stairs. It should be of such a section that it can be easily and comfortably grasped by the person ascending or descending the stairs.
Plan. Fig. 795.
Balusters (B) are the light upright posts or bars supporting the handrails between the newels, from the treads of the steps or string, and they can be square, moulded, or turned.
A flight is the series of continuous treads or risers, or steps, inclining from one landing to another, or connecting the different floors, if there are no landings.
A landing is the Bat space or floor at the top of the stairs.
A half-space landing is a similar flat resting space between two flights, one of which returns upwards in a direction opposite to the other, which goes down, as Figs. 795, 796. It is generally the width of the two (lights.
Plan Fig. 797.
A quarter-space is a landing half the size of the last-named, and extending across one flight only, the riser of the upward flight being at right angles to that of the downward one (Fig. 797).
The go or going of a stair is the distance from riser to riser, and the "rise" is that from tread to tread.
The going of a "flight" is the distance from first to last riser, between landings, or between the bottom and top of the stair.
Fliers are the ordinary steps, rectangular in tread or plane; while winders are those of triangular form, which are employed in turning comers or curves.
Curtail steps are those generally at the bottom of a flight or stair, which have one circular end to tread and riser; and in the centre of the tread the newel is placed, as Fig. 797A, the other end of the step being housed to the wall string in the ordinary way.
Bull-nosed steps are similar to the latter in form and use, but the end is only about a quarter of a circle in contrast to a "curtail" (vide Fig.
It will be readily understood that the success of a stair depends on the convenience and ease with which it can be ascended or descended - i.e., the go and rise of the step must be of suitable dimensions, and the flights short (i.e., of no more than a dozen steps) between a landing, half or quarter space, on which to rest if necessary.
Various rules have been drawn up to regulate the width of the tread or "go," in proportion to the rise of the risers; but the writer considers that the following scale of proportion gives the most comfort and ease to the user of the ordinary stair, while it is also a simple one for the student to remember.
Take 9 inches wide for the tread, and 7 inches high for the rise of the riser, as the standard or basis; and accordingly as the tread increases or decreases in width per inch, deduct or add 1/2 inch in rise respectively, therefore: -
A 5-inch tread
should have a
" 6 " "
8 1/2 " "
" 7 " "
8 " "
" 8 " "
7 1/2 " "
" 9 " "
7 „ „ (standard).
" 10 " "
6 1/2 " "
" 11 " "
6 " "
" 12 " "
5 1/2 " "
" 13 " "
5 " "
" 14 " "
4 1/2 " "
" I5 " "
4 " "
Section. Fig. 799.
Elevation Fig. 800.
Another rule is that the "product" of width of the tread, multiplied by the height of the riser, should equal 66 inches, which will be found to agree nearly enough with the above table, which 1 have given.
Of course it will be understood that these dimensions cannot always be carried out to the letter, on account of the varying circumstances, lengths, and heights met with in practice; but the principle can be always borne in mind, and regulated to the individual requirements.
The width of the stair or length of the step is also subject to variation, with the different positions and circumstances, but they should never be less than 2 feet 9 inches or 3 feet for ordinary use; and it is better that they should be of such a width that two persons can pass each other on the flight with ease.
In winding stairs, or places where there are winders, the full width of the tread in proportion to the rise should be placed where a person would put his feet when he is grasping the handrail in ascending or descending the stair; that is, about 18 inches from the centre of the handrail, or string.