Amount of Mortar. The thickness of the mortar joints should be about f to f of an inch. Thicker joints are very common, but should be avoided. If the bricks are even fairly good the mortar is the weaker part of the wall; hence the less mortar the better. Besides, a thin layer of mortar is stronger under compression than a thick one. The joints should be as thin as is consistent with their insuring a uniform bearing and allowing rapid work in spreading the mortar. The joints of outside walls should be thin in order to de crease the disintegration by weathering. The joints of inside walls are usually made from to finch thick.
The proportion of mortar to brick will vary with the size of the brick and with the thickness of the joint. With the standafd brick (81 X 4 X 2f inches), the amount of mortar required will be as follows: Thickness of Joints. Mortar required.
Per Cubic Yard. Per 1,000 Brick.
Cubic Yards. Cubic Yards.
to t- inch 0.30 to 0.40 0.80 to 0.90 " " 0.20 " 0.30 0.40 " 0.60 8 0.10 " 0.15 0.15 " 0.20 Face or Pressed Brick Work. 'This term is applied to the facing of walls with better bricks and thinner joints than the backing. The bricks are pressed, of various colors, and are laid in colored mortar. The bricks are laid in close joints, usually t-inch thick, and set with an imperceptible batter in themselves, which may not be seen when looking at the work direct, but which makes the joint a prominent feature and gives the work a good appearance: The brick of each course must be gauged with care and exactness, so that the joints may appear all alike. The bond used for the face of the wall is called the "running bond," the bricks are clipped on the back, and a binder placed transversely therein to bond the facing to the backing. The joints in the backing being thicker than those
of the face work, it is only in every six or seven courses that they come to the same level, so as to permit headers being put in. This class of work requires careful watching to see that the binders or headers are put in; it frequently happens that the face work is laid up without having any bond with the backing.
In white-joint the mortar is composed of white sand and fine lime putty. The mason when using this mortar spreads it care fully on the bed of the brick which is to be laid in such a way that when the brick is set the mortar will protrude about an inch from the face of the wall. When there arr a number laid, and before the mortar becomes too hard, the mortar that protrudes is cut off flush with the wall, the joint struck downwards, and the upper and lower edges cut with a knife guided by a small straight edge. When the front is built, the whole is cleaned down with a solution of muriatic acid and water, not too strong, and sometimes oiled with linseed oil cut with turpentine, and applied with a flat brush. After the front is thoroughly cleaned with the muriatic acid solution, it should be washed with clean water to remove all remains of the acid.
When colored mortars are required, the lime and sand should be mixed at least 10 days before the colored pigments are added to it, and they should be well soaked in water before being added to the mortar.