This section is from the book "A Treatise On Architecture And Building Construction Vol2: Masonry. Carpentry. Joinery", by The Colliery Engineer Co. Also available from Amazon: A Treatise On Architecture And Building Construction.
134. A dry cellar is one of the most essential requisites of a healthy house. A moist or damp cellar acts as a reservoir of chilly and impure air, and the constant movement of air in the living and sleeping rooms created by the warmer atmosphere, causes currents of this damp cellar air to rise through the inhabited rooms and become a menace to the health of the occupants. When basements are used for storage, it is also very necessary to guard against dampness in the cellar walls.
135. There are several ways of preventing moisture from entering the walls, either by applications of cement or asphalt to the outside of the walls, or by means of drainage.
If only surface water has to be guarded against, cement or asphalt placed on the outside of the cellar wall is usually found sufficient. It is often specified that foundations shall be cemented on the outside, from the footing to the baseboards of a frame house, or to the stone water-table of a brick house. When it is not desired that the cement should show above ground, the cement is usually stopped from 4 to 6 inches below the grade line.
Asphalt applied to the outside of a wall when boiling hot, is generally considered to be the most lasting and durable of all coatings. Its color, however, does not harmonize with either brick or stone work, hence it is usually put on under the ground or on the inside of cellar walls. When asphalt is applied, it is necessary to have the wall built as carefully as possible, with the joints well pointed; and the wall must be thoroughly dry before the coating is applied. The wall should have at least two coats of asphalt, carried down to the bottom of the footings.
136. Some clay soils, though sufficiently solid to support the walls of dwelling houses, still retain moisture in wet seasons that is not carried away into the earth, but rises in the cellar, keeping it almost always damp. Fig. 53 shows a method of damp proofing a cellar bottom and walls which has proved successful. The cellar is first prepared by laying 3 or 4 inches of sand, shown at a, which is to be rolled down firm and even. Around the cellar walls, shallow gutters b are made in the sand, and a coating of cement c, 1 1/2 to 2 inches thick, is laid over the whole surface of the cellar, with due care that sufficient descent is given to carry the water to the drain. When the cement is thoroughly dry, it is given a coat of asphalt, shown at d, over the entire surface of the floor, and through the walls at e, then up the outside of the wall at f, to the earth line or just below it.
137. Another method of securing a dry cellar is shown in Fig. 54.
The cellar bottom is leveled up smooth and even, spread with sand, as shown at a, to the depth of 4 or 5 inches, and well beaten down with a rammer to make it firm and hard. It is better to have the sand damp, as it packs better. On top of this the whole surface is covered with 1 1/2 inches of Rosendale or Portland cement b, which is carried well against the walls. The outside of the walls is then coated 1 inch thick with cement c, which is carried up to the ground line. When this is dry, the cellar bottom and outside walls are covered with hot asphalt, as shown at e. A pavement of hard-burned, good, even brick, dipped in asphalt, is then laid over the entire cellar, as seen at d.
138. When the cellar floor is only moderately damp, and there is no additional moisture after rains, a good bottom may be prepared by covering the cellar bottom with mortar composed of 6 parts of sand, and 1 part each of cement and lime. On this are laid 6" x 6" sleepers, preferably locust, and in the spaces between the sleepers, concrete is filled in. On this the wooden flooring is laid.
139. Another simple method of excluding moisture from cellars, is shown in Fig. 55. The excavation a is made wider than the building, so that there will be a foot or 10 inches left between it and the foundation wall. A V-shaped or semicircular tile drain, shown at b, should be placed at the bottom of this trench, after the wall is built, and connected with a horizontal drain, emptying either into the cesspool or sewer. The trench a should then be filled with loose stone, coarse gravel, and sand. If the top, for about 2 or 3 feet from the building, is then covered with stone flagging or cement d, it will assist greatly in keeping the walls dry. If the soil around the building is drained in this way, and the wall is coated with asphalt as shown at e, a perfectly dry wall can be obtained. The asphalt should be carried down to the bottom of the footings, as at f, and through the wall to the under side of the cellar floor, as seen at g.
140. A durable composition for a cellar bottom is made of 60 parts asphalt, 10 parts coal tar, and 30 parts sand. It should be used while hot. Cement and asphalt in equal parts are also used, and found durable for cellar bottoms. The ingredients should be mixed in a large pan or boiler, over a fire, and, when thoroughly mixed, spread over the surface.