This section is from the book "Cyclopedia Of Architecture, Carpentry, And Building", by James C. et al. Also available from Amazon: Cyclopedia Of Architecture, Carpentry And Building.
BUILDING FOR THE AMERICAN SCHOOL OF CORRESPONDENCE, CHICAGO, ILLINOIS.
COUNTRY HOUSE AT BETHLEHEM, N. H.
H. V. von Hoist, Architect, Chicago, Ill.
Plain stairs may have one platform, or several; and they may turn to the right or to the left, or, rising from a platform or landing, may run in an opposite direction from their starting point.
When two flights are necessary for a story, it is desirable that each flight should consist of the same number of steps; but this, of course, will depend on the form of the staircase, the situation and height of doors, and other obstacles to be passed under or over, as the case may be.
In Fig. 32, a stair is shown with a single platform or landing and three newels. The first part of this stair corresponds, in number of risers, with the stair shown in Fig. 33; the second newel runs down to the floor, and helps to sustain the landing. This newel may simply by a 4 by 4-inch post, or the whole space may be inclosed with the spandrel of the stair. The second flight starts from the platform just as the first flight starts from the lower floor, and both flights may be attached to the newels in the manner shown in Fig. 29. The bottom tread in Fig. 32 is rounded off against the square of the newel post; but this cannot well be if the stairs start from the landing, as the tread would project too far onto the platform. Sometimes, in high-class stairs, provision is made for the first tread to project well onto the landing.
If there are more platforms than one, the principles of construction will be the same; so that whenever the student grasps the full conditions governing the construction of a single-platform stair, he will be prepared to lay out and construct the body of any stair having one or more landings. The method of laying out, making, and setting up a hand-rail will be described later.
Stairs formed with treads each of equal width at both ends, are named straight flights; but stairs having treads wider at one end than the other are known by various names, as winding stairs, dog-legged stairs, circular stairs, or elliptical stairs. A tread with parallel sides, having the same width at each end, is called a flyer; while one having one wide end and one narrow, is called a winder. These terms will often be made use of in what follows.
The elevation and plan of the stair shown in Fig. 34 may be called a dog-legged stair with three winders and six flyers. The flyers, however, may be extended to any number. The housed strings to receive the winders are shown. These strings show exactly the manner of construction. The shorter string, in the corner from 1 to 4, which is shown in the plan to contain the housing of the first winder and half of the second, is put up first, the treads being leveled by aid of a spirit level; and the longer upper string is put in place afterwards, butting snugly against the lower string in the corner. It is then fastened firmly to the wall. The winders are cut snugly around the newel post, and well nailed. Their risers will stand one above another on the post; and the straight string above the winders will enter the post on a line with the top edge of the uppermost winder.
Platform stairs are often constructed so that one flight will run in a direction opposite to that of the other flight, as shown in Fig. 35. In cases of this kind, the landing or platform requires to have a length more than double that of the treads, in order that both flights may have the same width. Sometimes, however, and for various reasons, the upper flight is made a little narrower than the lower; but this expedient should be avoided whenever possible, as its adoption unbalances the stairs. In the example before us, eleven treads, not including the landing, run in one direction; while four treads, including the landing, run in the opposite direction; or, as workmen put it, the stair "returns on itself." The elevation shown in Fig. 36 illustrates the manner in which the work is executed. The various parts are shown as follows:
Fig. 34. Elevation and Plan of Dog-Legged Stair with Three Winders and Six Fivers.
Fig. 85. Plan of Platform Stair Returning on Itself.
Fig. 37 is a section of the top landing, with baluster and rail.
Fig. 38 is part of the long newel, showing mortises for the strings.
Fig. 36. Elevation Showing Construction of Platform Stair of which Plan is Given in Fig. 35.
Fig. 39 represents part of the bottom newel, showing the string, moulding on the outside, and cap.
Fig. 40 is a section of the top string enlarged.
Fig. 41 is the newel at the bottom, as cut out to receive bottom step. It must be remembered that there is a cove under each tread. This may be nailed in after the stairs are put together, and it adds greatly to the appearance.
We may state that stairs should have carriage pieces fixed from floor to floor, under the stairs, to support them. These may be notched under the steps; or rough brackets may be nailed to the side of the carriage, and carried under each riser and tread.
There is also a framed spandrel which helps materially to carry the weight, makes a sound job, and adds greatly to the appearance. This spandrel may be made of l 1/4-inch material, with panels and mouldings on the front side, as shown in Fig. 36. The joint between the top and bottom rails of the spandrel at the angle, should be made as shown in Fig. 42 with a cross-tongue, and glued and fastened with long screws. Fig. 43 is simply one of the panels showing the miters on the moulding and the shape of the sections. As there is a convenient space under the landing, it is commonly used for a closet.
In setting out stairs, not only the proportions of treads and risers must be considered, but also the material available. As this material runs, as a rule, in certain sizes, it is best to work so as to conform to it as nearly as possible. In ordinary stairs, 11 by 1-inch common stock is used for strings and treads, and 7-inch by 3/4-inch stock for risers; in stairs of a better class, wider and thicker material may be used. The rails are set at various heights; 2 feet 8 inches may be taken as an average height on the stairs, and 3 feet 1 inch on landings, with two balusters to each step.
Fig. 37. Section of Top Landing, Baluster, and Rail.
Fig. 38. String Mortises in Long Newel.
Fig. 39. Mortises in Lower Newel for String, Out-side Moulding, and Cap.
Fig. 40. Enlarged Section of Top String.
In Fig. 36, all the newels and balusters are shown square; but it is much better, and is the more common practice, to have them turned, as this gives the stairs a much more artistic appearance. The spandrel under the string of the stairway shows a style in which many stairs are finished in hallways and other similar places. Plaster is sometimes used instead of the panel work, but is not nearly so good as woodwork. The door under the landing may open into a closet, or may lead to a cellarway, or through to some other room.
Fig. 41. Newel Cub to Receive Bottom Step.
Fig. 42. Showing Method of Joining Spandrel Rails, with Cross-Tongue Glued and Screwed.
In stairs with winders, the width of a winder should, if possible, be nearly the width of the regular tread, at a distance of 14 inches from the narrow end, so that the length of the step in walking up or down the stairs may not be interrupted; and for this reason and several others, it is always best to have three winders only in each quarter-turn. Above all, avoid a four-winder turn, as this makes a breakneck stair, which is more difficult to construct and inconvenient to use.