Even in the heart of stone-districts bricks are now generally used for all internal walls, and for all but the facing of external walls. Their cheapness, and the facility with which they can be laid, have led to their adoption in lieu of rubble. Brick walls are also straighter than rubble walls, and require less plaster.

For cottages and small villas, external walls from 12 to 15 inches thick are often used; they consist of an outer skin of stone about 6 inches on the bed, and an inner lining of 4-inch brick, the space between being either left as a cavity or filled with mortar and scraps of stone and brick. This filling is almost invariably scamped, and, consequently, instead of rendering the wall more solid and impervious, actually facilitates the passage of damp by affording points of contact between the stone and brick. These walls have usually one stone through in every square yard, and two natched or rebated throughs (see Fig. 35) to each jamb of door and laid with Outward sloping Beds.

Stone And Brick Walls 10038Fig. 34.   Stone Wall with Bond stones A and B

Fig. 34. - Stone Wall with Bond-stones A and B.

Fig. 35.Window Reveal with Natched Through. stone

Fig. 35. Window Reveal with Natched Through. stone.

window. Sometimes, however, cast or wrought iron ties are used instead of through-stones, and are to be preferred in the case of hollow walls, as stone throughs form bridges, or rather aqueducts, conveying rainwater across the cavity to the brick and plaster within.

For larger buildings, and wherever the additional expense can be afforded, thicker walls should be used. These may be. formed as shown in Fig. 36, where the heart of the wall is formed with rubble. This gives an opportunity for substituting bond-stones as at a for the through-stones previously mentioned, and the brick lining may be tied to the body of the wall either by inner bond-stones as B, or preferably by rows of headers every fourth or fifth course as at cc. The latter method is desirable where glazed bricks are used, and where the brickwork will not be covered with plaster. The mortar in walls of this kind should be of good quality - made from hydraulic lime or cemeut if possible, - and the walls will be improved by being run with grout Frequently stone-and-brick walls of considerable thickness are simply brick walls with a facing of stone, added for the sake of appearance or to preserve the bricks from atmos-pheric agencies. In such cases, the thickness of the ashlar courses may he some multiple of the thickness of the brick coures. An arrangement with alternate bonding-courses of stone is sometimes adopted, as shown in Fig. 37.

Fig. 36  Wall with Aahlar Facting. Brick Lining, and Babble Hrarting.

Fig. 36- Wall with Aahlar Facting. Brick Lining, and Babble Hrarting.

A,.outer bond-stone; B. Inner bond-stone; CC. brick head.

Fig. 37. Brick Wall with Ashlar Facing having Alternate Bond courses.

Fig. 37.-Brick Wall with Ashlar Facing having Alternate Bond-courses.