ROOD LOFT, an elevated loft or gallery occupying a position to the rood-beam, but resting or appearing to rest on a screen below. It was usually spread out front the top of the screen on both sides of it, so as to give a landing at top of sufficient space for the rood-screen, and for the passage of persons to and fro. It was from this place that a part of the Romish service was performed. The soffit of the loft on either side of the screen, was either coved, or in the form of a semi-vault, with groining and ribs. The loft was approached by a staircase in the chanceLpier or main walls of the church, and these are frequently the only evidence of the existence of the loft.
Roon-ScnEax, the screen of open work which in most churches separated the nave and .chancel ; the lower portion being panelled, and the upper perforated with rich tracery. work in the head. In the centre was a door, or pair of gates giving admission to the chancel. Such screens were usually of wood, but sometimes of stone, especially in cathedrals and larger churches ; they are also sometimes double ; as at St. David's Cathedral, and Gilden Morden, Cambridgeshire. Rood-screens, as well as the loft, and rood itself, were often ° of most elaborate workmanship, highly decorated with gild and colour.
Row) TOWER, the tower at the intersection of nave and transepts.
ROOF, (from the Saxon, prof,) the cover, or top of a build ing, generally consisting of two sloping sides, though occa sionally of other figures.
The ancient Egyptians, Babylonians, Persians, as well as other Eastern nations, had their roofs quite flat. The Greeks • appear to have been the first who made roofs with a declina tion each way from the middle to the edges ; this was very . gentle, the height from the ridge to the level of the walls not exceeding one-ninth or one-eighth part of the span, as may be seen by many ancient temples now remaining. In northern climates, subject to heavy rains and falls of snow, the ridge must be very considerably elevated. In most old buildings in Britain, the equilateral triangle seems to have been con sidered as the standard, both in private and public edifices ; and this pitch continued for several centuries, till the disuse of what is called Gothic architecture. The ridge was then made somewhat lower, the rafters being three-fourths of the breadth of the building. This was called true pitch ; but, subsequently, the square seems to have been considered as the true pitch. The heights of roofs were gradually depressed ,from the square to one-third of the width, and from that to la fourth, which is now a very general standard ; though they have even been executed much lower. There are some advantages in high.pitched roofs, as they discharge the min „with greater ; the snow continues a much shorter 'time on *the surface, and they are less liable to be stripped by heavy winds. Low roofs require large slates, and the utmost
; care in execution ; but they have the advantage of being much cheaper, since they require shorter timbers, and of a much less scantling. When executed with judgment, the roof is one of the principal ties to a building ; as it binds the exterior walls to the interior, and to the partitions, which act like strong counterfoils against them.
Roofs are of various forms, according to the nature of the plan, and the law of the horizontal and vertical sections. The most simple form of a roof is that which has only one row of timbers, arranged in an inclined plane, which throws the roof entirely to one side. This is called a shed-roof, or lean-to. The most elegant roof for a rectangular building, consists of two rectangular planes, of equal breadth, equally inclined, and terminating in a line parallel to the horizon ; consequently, its form is that of a triangular prism, each side being equally inclined to the plane of the wall-head. This is sometimes called a pent-roof When the plan is a trapezium, and the wall-heads properly levelled, the roof cannot be executed in plane surktees, so as to terminate in a level ridge. The sides, therefore, instead of being planes, are made to wind, in order to have the sum mit parallel to the horizon ; but the most eligible method is to make the sides of the roof planes, enclosing a level space, or flat, in the form of a triangle, or trapezium, at the summit of the roof. Roofs flat on the top are said to be truncated : these are chiefly employed with a view to diminish the height, so as not to predominate over that of the walls.
When all the four sides of the roof are formed by inclined planes, it is said to be hipped, and is, therefore, called a hipped-roof ; and the inclined ridges springing from the angles of the walls are called hips. Roofs of this descrip tion are frequently truncated ; and when the plan of the walls is in the form of a trapezium, the truncation of the roof becomes necessary.
Roofs upon circular bases, with all their horizontal sections circular, the centres of the circles being in a straight line drawn from the centre of the base perpendicular to the horizon, are called revolved-roofs, or roofs of revolution.
When the plan of the roof is a regular polygon, or a circle, or an ellipsis, the horizontal sections being all similar to the base, and the vertical section a portion of any curve convex on the outside, the roof is called a dome.
To save the expense of lead in the roofs of rectangular buildings, instead of the flat, a valley is sometimes used, which makes the vertical section in the form of the letter M, or rather an inverted W ; and hence it has obtained the name of an if roof.