Fig. 818 is a section of the treads and risers of a common narrow stair between two walls. The treads have rounded nosings, and are grooved and tongued to the risers, glued together, blocked and housed into the strings, and wedged up finally.
Sectional Elevation, on Line A B.Fig.815 Fig. 816.
Winders are similar in detail, but their section depends of course upon where it is taken, and which wide or narrow part of the tread it cuts through, as A B or C D, Fig. 819, the latter of which cuts the risers when close together.
Both of the strings, in this case, being wall strings, their sections will be similar to Fig. 820, which is a section on line AB in Fig. 818. The string is housed out for each end of a step, with its wedges to riser and tread, as Fig. 821, in elevation.
Where strings meet at right angles they are either grooved and tongued together, or dovetailed; and where there are winders, at either comers, or junctions of raking with straight, they are eased off, as X, Figs. 823 and 823, which are called ramps.
In better stairs, the section of treads and risers is as Fig. 824, from which it will be gathered that the strings are deep, being 11 inches in lieu of 9 inches, and the nosings moulded, the small hollow fillet being housed into the underside of the tread, and dispensing with the tongue on the top of the riser. And in addition to the gluing, blocking, housing, and wedging to strings, where the steps are wide, they have an extra support in the form of a rough bearer called a carriage, which inclines from bearing to bearing, parallel to the string supporting the under-side junction of treads and risers in the centre of the stair, as Figs. 825 and 826. This also entails additional depth of string, as X, the top dotted line representing where the underside of the string would have been without the carriage.
Oftentimes a further addition to the "glued, blocked, housed, wedged, and supported by fir carriages," is made by screwing shaped brackets on to the side of the carriage to support the treads of the steps, as Fig. 827, the carriage only being a help to the risers and the stair, as a body. (See also section, Fig. 828.)
When each flight of stair has not a wait on each side of it for wall strings, the other string, which is not against a wall, is called an outer string. Consequently, it must be stouter, and more ornamental and taking to the eye on the outside, as Fig. 830, which shows handrail, etc., in elevation, Fig. 831 being a plan of the same. The string is as Fig. 819 in section, or it may be more elaborate still, and consist of string, S; capping, C; and fascia, F; as Fig. 832.
Strings should always be tongued at headings, and either grooved and tongued, or dovetailed, at all angles, housed into the centre of all newels, and pinned in, as in Fig. 833. If they are moulded the housing has to be scribed for the mouldings to fit in as well.
Handrails are also scribed, housed, and pinned to all newels, and should be fixed 2 feet 8 inches above each tread, measured in a line from the face of the riser, as Fig. 834. On landings and flat places they should be 3 fee 1 inch high. Fig. 835 presents a rounded or mopstick handrail in section Fig. 836, a moulded handrail; and Fig. 837, a toadsbaek moulded handrail, so called because of its fiat curved top.
The balusters are housed into the strings and handrail, as shown above; but sometimes, especially when of iron, they are connected together by an iron core, which is secured on to the top of them, as Fig. 839, and the core, in its turn, is let into and screwed to the underside of the handrail, as Fig. 840.
A handrail should always have a curved top face and no arrises, and be of such a size that it can be easily grasped. Fig. 838 is a section of one suitable for a winding geometrical or wreathed stair.
Newels are generally cut out of square stuff, and either left square, moulded, or turned. They are the mainstay of the stair and the connecting link between the flights, as every string should be framed and pinned into them, and the risers of the steps next to them ought always to be housed into their centre, as previously shown.
When newels are not framed at both ends, from floor to floor, they have either rounded or turned tops, when their foot is framed and secured as at the bottoms and tops of stairs; and where they occur between landings or flights, and are not framed at either of their ends into floors, etc, but to the trimmers sideways, as Figs. 841 and 841, they have a moulded or turned top, and the bottom is turned and ornamented as well and called a pendant or drop, as Fig. 843, which is a representation of the newels at a half-space landing on an open-newel stair.
Landings, whether half or quarter-space, are made of flooring boards carried on ordinary joists framed into the trimmers, to which one (light inclines, and from which the other starts, as Fig. 844, which represents a half-space landing.