The chief considerations to be borne in mind in choosing the material for a floor are: (1) wearing resistance, (2) comfort to the feet, (3) retention of warmth, (4) capability of being laid evenly and repaired conveniently. When the first condition is most essential and the second is unimportant, as in public places where there is great traffic, some form of masonry is best adapted; but for comfort, on the score of elasticity under foot and a generally heat-conserving quality, wood is unsurpassed, especially the ordinary boarded floor. In situations subject to much wear, wood-block flooring is better adapted. The blocks are generally laid to the "herring-bone" pattern upon a concrete bed, and can be equally employed for upper floors on rolled joists filled in with concrete, making a remarkably firm, durable, and comfortable floor, not too resonant or noisy for large rooms, and in every respect more sanitary than the ordinary boarded floor The blocks, being of a brick proportion, can be laid as parquetry, or in squares placed diagonally the blocks alternating in direction. The shrinkage is reduced to a minimum and when the blocks are well bedded and secured to the bed, as in Lowe's patent com-position, no more durable flooring can be employed.

This composition is said to prevent dry-rot. A more decorative sort of wood flooring is parquetry. The solid Swiss parquetcrie consisted of pieces about 1 in. thick, grooved and tongued together and secured by marine glue. Wood veneers, backed by kamptulicon and other substances have been similarly used for effect. Thin parquet laid on a patent composition or glue (Eberhard's) is a kind of flooring that has been used with much success oven on stone foundations; and stone paved floors and staircases worn hollow have been treated by this process, the unevenness of the surface being made up by the glue, which becomes a hard yet slightly elastic backing. Some parquet, as that of Turpin's, is only 5/16 in thick, and is prepared on a deal back, and the floor is said to be equal in wear to 1-in solid parquetry. The plan of fixing thin plates of hard ornamental woods in geometrical patterns upon existing hard floors is one that will commend itself. Of all floorings there is perhaps hardly any so appropriate, so comfortable, or so artistic as parquetry, and even the plain hard woods like teak admit of being used decoratively. The custom of carpeting over the centre of the room only, allowing a border of the real floor to be seen lends itself to parquetry borders.

Smaller carpets and of better quality or design would be selected, while cleanliness and sanitary conditions would be the result of the change. There are many manufacturers who can supply borders at the low price of 6d.. per sq. ft. A solidly-backed parquetry floor, supported upon joists partially filled up with concrete, forms an almost impassable barrier to fire. Even wooden joists, well protected by a fire-resisting plaster ceiling, or the interspaces filled up, has been found to stay the ravages of fire, while a closely-jointed block or parquet floor, laid on a good backing, is impervious to air, and would retard the progress of flames above or below it. For the floors of hospital wards no floor can be more suitable or so comfortable.

Passing now to a consideration of the most usual form of flooring, that by parallel boarding, the first feature to be explained is the arrangement of the beams and joists which are to support the boards. It may, however, be well to premise, that, as wood is found to be much more durable when exposed to the air than when built in brickwork at the ends, an effort is always made to secure that condition, and the other ends of the beams or joists are most commonly supported on wall-plates fitting into the space occupied by a course of bricks. Fig. 637 shows a simple method of securing the tie beam a to the wall-plate b lying on the brickwork c, the beam a being notched out on the under side to admit b. In Fig. G38 this joint is strengthened by the addition of a key or cog d fitting closely into grooves in a and b. Figs. 639, 640 illustrate the junction of the poleplate a to the tie beam b, both with and without the intervention of a key or cog c. Other methods of securing the joist a to the wall-plate 6 are shown in Figs. 641, 642, 643. In Fig. 644 the joist a, instead of lying flat on the upper surface of the wall-plate b, is connected by a mortice and tenon joint, the under side of the joist being mortised as at c, while a tenon d is cut into the wall-plate.

Floors 635Floors 636Floors 637Floors 638Floors 639

The special uses of the 'several kinds of joist will be best described when speaking of the sort of floor in which they are employed; but it may be well here to state their respective scantlings, i. e. their sectional dimensions. They vary of course with the length of the bearing (the distance between the supports that hold them), as given in the first column of figures:-

Floors 640Floors 641Flooring joists, 1 ft. apart.

Flooring joists, 1 ft. apart.

ft.

in. in.

in. in.

in. in.

5 .............

4 x 2 1/2

4 1/2 x 2

3 1/2 x 3

10 ...............

9 x 1 1/2

7 x2 1/2

15 ..........

11 x 1 1/2

10 X 2

9 x 2 1/2

20 ..........

11 x 3

10 x 4

25..........

12 x 3

11 x 4

Binding joists, 6 ft. apart.

ft.

in. in.

in. in.

7 x 3

9 x 2

7ft. Gin.......

9 x 3

10..........

9 x 4

11 x 3

12 ft. 6 in.......

11 x 4

15..........

12 x 4

20..........

13 x 6$

15 .. 7 1/2

Ceiling joists, 1 ft. apart.

ft.

in. in.

in. in.

4 ....................

2 1/2 x 1 1/2

2 x 2

5 .............

2 1/2 x 2

6 ..........

3 x 2

7 ..........

3 1/2 x 2

3 x 2 1/4

8 ...........

4 x 2

3 x 2 1/2

9 ............

4 1/2 X 2

4 x 2 1/2

10 ..............

4 1/2 x 2 1/2

4 x 3

12 ................

5 x 3

14 .................

6 x 3

Girders, 10 ft. apart.

ft.

in. in.

in. in.

10..........

11 x 5 1/2

12 x 4

15..........

13 X 6 1/2

11 x 11

20..........

15 x 7 1/2

13 x 13

25..........

17 x 8 1/2

14 x 14

30..........

20 x 10

Flooring boards are generally cut 6 7/8 in. (7 in. planed up) wide, but can also be had A\ in. and 5 1/4 in. wide; in thickness they run 3/4 in., 1 in., 1 1/4 in. and 1 1/2 in., at least they are called after these measurements, but are really somewhat less owing to planing.