Brick walls are sometimes built with a 4-inch inner and outer facing connected with solid brick withes, as shown in Fig. 155, the air space being made 4, 8 or 12 inches, according to the height and character of the building. Congress Hall, Saratoga, N. Y., a portion of which is seven stories high, is built in the manner shown in Fig. 155, and has stood successfully. If such a wall is built of the quality of brick generally made in the New England States, and with perfect workmanship, it should have ample strength for any ordinary three or four-story building, and would certainly be more stable and conduct less heat and moisture from and into the building than a solid wall of one-half more bricks. With such bricks and workmanship as are commonly found in many portions of the country, however, walls built in this way should never be used for any building larger than a two-story dwelling. Theoretically, the inside of the wall opposite the withes would be subject to dampness, but, of course, not to as great an extent as with the solid wall.
For two-story dwellings, this wall, if well constructed and the withes securely bonded to the facings, should make a much more healthy and comfortable building than the solid wall.
For office buildings furring blocks designed for that especial purpose are often used for lining or furring the external walls, and sometimes hollow bricks are used for the inner 4 inches of a solid wall, but the latter have not proved a success in excluding moisture. The objection to any kind of furring and to hollow brick is that there must necessarily be some connection between the material of the lining or furring and the wall, and this connection allows of the passage of heat and moisture.
It is quite common in many sections of the country to build dwellings, and even three and four-story buildings, with the outer walls of frame construction and then to veneer the frame with a 4-inch facing of brick. Buildings built in this way have the same appearance, both externally and internally, as if the walls were entirely of brick.
Where lumber is cheap and brickwork comparatively expensive this method of construction possesses some advantages, although it is not generally approved by architects, and should only be used where a hollow brick wall cannot be afforded. The advantages possessed by a brick-veneered frame wall over a solid brick wall are that it costs less and the air spaces prevent any possibility of the passage of moisture, and also makes the house much warmer in winter and cooler in summer.
About the only advantage that it possesses over a well-built frame building is that it reduces the insurance rate, as the veneer offers some protection from fire in adjoining buildings. A veneered building, however, is not near as safe from fire as a brick building, and would probably be destroyed by fire on the inside about as rapidly as though the frame were covered with siding or shingles.
The only differences in the planning of a veneered building from that of a frame building are that the walls are 5 inches thicker, the foundations must project sufficiently beyond the frame to support the veneer, and the elevations are drawn the same as for a brick building.
The wooden frame should be constructed in the best manner, with at least 4x6 sills, 4x8 posts, 4x6 girts and 4x4 plates, and be well braced at the angles. After the frame is up it should be sheathed diagonally and then covered with tarred felt.
It is also very important that the framing timber shall be as dry as possible, particularly the sill and girts, and the frame must be perfectly plumb and straight.
The veneer is usually laid with pressed or face brick, with plumb bond, which should be tied to the wooden wall with metal ties. The Morse tie, shown at a, Fig. 156, is probably the best for this purpose, although the author has used the tie shown at b with very satisfactory results. The ties should be placed on every other brick in every fifth course.
In laying out the wall on the floor plans 6 inches should be allowed from the outside of the studding to the face of the wall. This gives an air space of about 1 inch between the brick and sheathing and avoids chipping the bricks where the wooden wall is a little full. It is a good idea to build a 2-inch U-shaped drain tile in the foundation wall under the air space to collect any moisture that may penetrate the veneer. The air space should also be ventilated at the bottom through 2-inch drain tile, as shown in Fig. 157.
The top of the brickwork generally terminates under the eaves or gable finish. If the building has a flat roof, with parapet walls, the latter should be coped with either copper or galvanized iron and tinned on the back down to the flashing.
Fig. 157 shows a partial section through the foundation and a portion of the first story wall of a veneered dwelling to illustrate the construction described above.