Page:Encyclopædia Britannica, Ninth Edition, v. 4.djvu/502

454 BUILDING [CONSTEUCTION. or 40 feet ; and walls of such lengths and heights could hardly be deemed safe if not more than one brick thick. Consequently, a greater thickness has been prescribed as the least thickness of the walls of buildings of the sizes indicated. In the older Metropolitan Building Acts much greater thicknesses were prescribed for the walls likely to be the longer walls ; whilst the only necessity for more than one brick rises from structural requisites, and not from any insufficiency of a wall of solid brickwork one brick thick as a means of preventing the spread of fire. Partitions. But the requisites of the structure would be as well fulfilled by one-brick walls upon the long sides as by 1|- brick walls, if the ordinary internal cross partition for dividing a house into front and back rooms were built of brickwork abutting upon, and at right angles to, the longer walls, and carried up coursed and bonded with them. That is to say, party-walls of one brick or 9 inches in thickness, connected at their -ends by l|-brick or 13-inch front and back walls, and at or about the middle of their length by other 9-inch cross walls, would be at the least as strong as 1^-brick party-walls, though connected in the same manner at the two ends, but without the abutting and connecting cross wall of brickwork. Instead, however, of such internal cross walls, hollow partitions of timber are commonly used in all stories above the basement story ; and it is by these partitions, and by the light and highly inflammable wooden stairs, that fire extends itself rapidly throughout ordinary dwelling-houses ; whilst the substitu tion of a brick wall for the cross timber partition would in most cases justify the abatement of a half brick of the thickness otherwise necessary to party-walls, and give an indestructible internal support to the floors, whereby also one of the means by which fire travels rapidly through a house would be removed. It is true that there must be openings as doorways, and fittings in them for doors, in such internal partition wall ; but the wall could not carry fire up from floor to floor through its own heart, as the hollow wood-lathed quartering partition carries it. Doors and shutters, and door window linings, in and against brick or stone walls, may take fire and burn in any story of an ordinarily built dwelling-house, without carrying it (beyond the story in which the fire occurs ; for a plastered ceiling of the most common description will resist the action of ilame upon its surface for a long time, and plastering of really good quality, though upon wood laths, will keep fire off from the joists by which it is held up, almost without danger, so long as the fire acts upon the face only of the plastering. If, however, fire reach the joists through the agency of hollow quartering partitions, the enemy has turned the flank of the plastering, and the floors and skirtings above and behind it taking fire, the building almost inevitably falls a prey to the flames. Any step, iudeed, from the hollow quartering partition towards a solid wall is a step towards security. A brick wall is, perhaps, the best internal partition for all the purposes of strength and security from fire ; and in small houses, which will not afford the expense of 9-inch walls, half-brick walls with 9-inch jambs at the doors, and short 9-inch piers on alternate sides of the partition, at intervals of 3 or 4 feet in length, will give sufficient strength ; but even quartering partitions, if based upon brick walls, may be rendered nearly proof against fire by brick-nogging them, especially if care be taken to fill in with brickwork between the joists over the head of one partition and under the sill of another, as well as between the timbers of the partitions. Filling in between the joists, and up as high as the skirtings go, will do something, indeed, towards diminishing the Partitions dangerous tendency of even lathed and plastered timber as formed partitions ; whilst the adoption of the plan now commonly in Paris, practised in Paris, in forming not only internal partitions, but the rearward external enclosures of buildings, would secure to the structure the structural efficiency of timber on end in carrying weight, and give the solid and incom bustible character of a brick or stone wall to a partition or enclosure which is structurally of timber. The plan referred to is, to frame and brace with timber quarterings much in the manner practised in England, except that the timber used in Paris is commonly oak, and is generally seasoned previously. The framed structure being complete, strong- oak batten-laths, from 2 to 3 inches wide, are nailed up to the quarterings horizontally, at 4, 6, or even 8 inches apart, according to the character of the work, throughout the whole height of the enclosure or partition ; and the spaces between the quarterings, and behind the laths, are loosely built up with rough stone rubble, which the laths prevent from falling out until the next process has been effected. This is, to apply a strong mortar, which in Paris is mainly composed of plaster of Paris, which is there of excellent quality, laid on from both sides at the same time, and pressed through from the opposite sides so that the mortar meets and incorporates, embedding the stone rubble by filling up every interstice, and with so much body on the surfaces as to cover up and embed also the timber and the laths in such a manner, indeed, as to render the concretion of stone and plaster, when thoroughly set, an independent body, and giving strength to rather than receiving support from the timber. The English brick-nogged partition is, in point of struc- Partition: ture, nothing without the aid of timber. The plastering ? s !:, orn ? ( * is merely spread upon the surfaces of brick and wood, m and is fragile in the extreme, and always liable to crack and drop off. This lathed and plastered partition is composed of the hollow framework of the timber quarters, with two slight thicknesses of mortar, as plastering, hung upon slighter laths, over and between which the flaccid mortar forms a key for itself ; but all necessarily depends upon the timber, and fails with it wherever decay or fire may destroy it. Only second in importance to the internal partition as a Stairs, source of danger, or as a means of safety, are the stairs; and the stairs are second in importance only when the partitions are made to carry the floors of the several stories. In England, and in London particularly, even when the steps and intermediate landings are of stone, it is but too common to find the passage from the street door to the foot of the stairs, and the floors which connect flight with flight at the several landings, either wholly of wood or of slight stone paving laid upon wooden joists or bearers. Any stone paving upon wooden joists will certainly retard the action of fire upon the joists, especially if assisted by a well-plastered ceiling ; but in this, again, if the floors be not formed of wholly incombustible materials, the French practice as to floors would be better than ours. In Paris stone stairs are far less common in modern houses than they are in London in houses of corresponding character and date; but wooden staircases in Paris are rendered almost as safe as common stone staircases are in England, by a process similar in character to that applied to partitions and enclosures. The result is un almost incombustible structure. Wooden staircases formed between brick or stone walls, or between partitions of the kind above described as commonly made in modern buildings in Paris (that is, filled with a solid mass of concreted rubble), may perhaps be set on fire, but they can hardly burn. It has been remarked that a mere plastered ceiling will Ceilings resist the action of fire for a long time, although the plas- ancl floors toring be upon wooden laths, and the laths nailed to joists of timber; and as fire does not readily act downward!?, flooring boards may take fire from above without any

immediately serious consequence to the joists under them,