Cased frames are generally secured in position by wedges, or pairs of wedges, driven in at the sides between the back linings of the boxes, or cases, and the masonry; and at the head by wedges between the top of the frame and the soffit of the relieving arch or lintel. (These last-mentioned wedges should be driven in over the pulley styles, so that they may not bear upon the unsupported part of the head of the frame and cause it to bend.) The frame should, however, be made more secure at the sides by being nailed obliquely through the inside linings, and wedges where they occur, to plugs, wood bricks, or breeze fixing blocks inserted at intervals in the masonry or brickwork (see Figs. 95, 96, 544), and at the top by being nailed to plugs inserted in the inner flat arch, or directly to the concrete or wood lintel, according to the construction adopted. When the inside lining is attached to the wood lintel, it should be nailed only near the ends of the lintel where it bears upon the wall, so that the lintel may be free to sag in the centre without bearing on the frame.
Cased frames are often built in as the walling progresses, in which case the head should be made longer than the width of the frame, so as to form horns somewhat similar to those of the solid door frame shown in Fig. 532, but much sounder work is made if the frames are fixed after the brickwork is complete; screeds can then be run up to which the frame can be accurately fitted.
In exposed places they should be made to open outwards, as then the wind pressing upon them from the outside only makes them close more tightly.
The frames for these windows are solid, having a rebate cut round the outside to receive the sash.
The back of the hanging style of the sash is generally shaped so as to fit into a circular recess formed in the frame, as shown at x, Fig. 551, in order to make the joint as tight as possible.
These sashes have continuous horizontal bars, the vertical bars, if any, being framed into them.
It is difficult to keep the wet from entering these windows, especially if the sashes are hung folding in two leaves.
To prevent this various methods have been devised; among the best is the curved groove on one style and corresponding projection on the other fitting into it, as shown in the figure.
Fig. 551. The joint is often further protected by a cocked bead (cb) planted on the outside.
The frames of casement windows are often placed so as to be flush with the face of the wall, in order that the sashes may fold back against the wall when open.
"When a casement window extends down to the floor it becomes in fact a glass door, and is often made to open inwards; in such a case it is very difficult to keep water from entering between the foot of the door and the sill, which, if rabbeted, is so necessarily on the inside. To overcome this objection several different plans have been adopted.
One of these is shown in Fig. 552. The rain is prevented as much as possible from beating in at the joint by a moulded and throated weather board, and by a metal water bar fixed in the oak sill. Any wet that may penetrate between these is caught in the groove formed in the sill at the back of the water bar, and conveyed away through a hole bored in the oak sill as dotted.
In this arrangement the water bar is rather in the way of any one entering the door. To avoid this it is often omitted, or " self-acting water bars" are used. These are attached to the lower rail of the sash, move with it, and when it is shut, turn over to secure the joint. Any detailed description of these contrivances would be beyond the range of this Course.
In order to get rid of the water penetrating between the frame and the sides of the sash, the rebate in the former is grooved down the centre, and a similar groove is formed down the side of the style of the sash. These two grooves meeting one another form a channel down which the water runs into the groove behind the water bar aboved noticed.
The description of the different kinds of furniture and hinges in use does not fall within the range of this course, but it is required that the student should know the position in which they are fixed (see Syllabus).