Masonry Magazine January 1962 Page. 44
Determining Brick Placement with a Marked Line
To determine brick placement with a marked line, first select a representative sample of the range of units that will be laid in the wall. Now lay the 10 selected brick end to end on a level spot, being certain that they are pushed snugly together. Measure the entire length of the 10 brick. With this total length, check in the left hand column of Table I for a dimension nearest the length. For example, if the measured length is 81 7/8 in., the nearest dimension in the table would be 81 7/8 in. This dimension falls in the lower portion of the table and tells us that a non-modular marked line must be used.
The number of brick that go in a wall depends upon the average length of the brick and the size of head joint to be used. A 3/8-in. head joint is most commonly used with facing brick, but sometimes a 1/4-in. head joint is desired. Table I lists multipliers for either 3/8-in. or 1/4-in. joints. For our example we will use 3/8-in. joints. Since the dimension picked in the table was 81 7/8 in., follow horizontally across the table to the center column which lists the multipliers for 3/8-in. joints. The multiplier is 467. This number, multiplied by the wall length, will give the number of red marks to count off when stretching the marked line.
TABLE I
CONVERSION TABLE STANDARD BRICK LENGTHS TO RED MARKS ON LINE
| Total Length of 10 brick (inches) | Multipliers With 3/8" Joint | With 1/4" Joint |
|---|---|---|
| 75 | 508 | 500 |
| 75 3/8 | 504 | 497 |
| 76 1/8 | 500 | 493 |
| 76 5/8 | 497 | 489 |
| 77 3/8 | 493 | 485 |
| 78 1/8 | 489 | 481 |
| 78 5/8 | 485 | 478 |
| 79 3/8 | 481 | 474 |
| 80 | 478 | 471 |
| 80 5/8 | 474 | 467 |
| 81 3/8 | 471 | 463 |
| 81 7/8 | 467 | 460 |
| 82 3/8 | 464 | 457 |
If the wall length happens to be in full feet, the problem is simple. However, if the length is in feet and inches, the inches must first be converted to a decimal portion of a foot. Table II converts inches to decimals of a foot. Assume the wall length to be 47'9". Enter Table II at 9 in. and follow horizontally across to the decimal, which, in the case, is 0.75. Thus the wall length will be 47.75 ft.
TABLE II
| Inches | Decimal Equivalent of Feet | Inches | Decimal Equivalent of Feet |
|---|---|---|---|
| 1 | .08 | 7 | .58 |
| 2 | .17 | 8 | .67 |
| 3 | .25 | 9 | .75 |
| 4 | .33 | 10 | .83 |
| 5 | .42 | 11 | .92 |
| 6 | .50 | 12 | 1.00 |
To determine the total number of red marks to be counted off on the line, multiply the wall length by the multiplier selected from Table 1:
47.75 x 467 = 22.29 red marks
Thus there are 22 red marks with a decimal portion left over, in our example 0.29.
Since the red marks on the line are 3 brick apart and the black marks are a half brick apart, there are 6 spaces, or 5 black marks, between each two red marks. The decimal left over must then indicate the number of black marks to be added after the last red mark has been counted. Table III converts these decimals to black marks.
TABLE III
CONVERSION TABLE-RED MARKS TO BLACK MARKS
| Decimal Red Mark | Black Marks |
|---|---|
| 0.16 | 1 black mark |
| 0.33 | 2 black marks |
| 0.50 | 3 black marks |
| 0.67 | 4 black marks |
| 0.83 | 5 black marks |
Our decimal 0.29 is nearest to 0.33 in the table. Therefore, it will be necessary to add 2 black marks to the red marks. If the number of black marks is even (2, 4), it indicates that the wall can be bonded with whole brick. However, if the number is odd (1, 3 or 5), there must be a half brick or header at one corner of the wall.
In our example, 2 black marks must be added, so we can start with either headers or stretchers at both corners since the two marks represent a whole brick.
Next, place a brick at each corner of the wall. We will use headers in our example since they equal the 2 black marks. This leaves only the 22 red marks between the headers. See Figure 8.
Fasten one end of the marked line to a line holder at one corner pole so that the first red mark is about one brick back from the inside edge of the corner header. When the line is stretched, this red mark should form the head joint of the header. Then count off 22 red marks on the line, being certain your count is correct. The line should now be stretched and fastened to the line holder at the opposite corner so that the 22nd red mark forms the head joint for the header at that corner. Next, check the first mark to see that the line has stretched enough so that it forms a proper head joint for the first header. If it does not, simply slack off on the line at that end until the first mark is properly positioned.
The masons can now begin laying brick at any mark on the stretched line. There is no guessing, as the bonding of every brick has its space indicated along the line.
Stretching the Marked Line for Roman, Norman Brick or Structural Clay Tile- and 4" x 10" Closure Units
The method of sampling the brick or tile is the same as described before. Pick out 10 units, selecting shapes and colors in proportion to their occurrence in the stock. After the units have been placed snugly together end to end, the total measured, enter Table IV at the dimension nearest the measured dimension. Select either a 3/8-in. or 1/4-in. joint and obtain the multiplier under the appropriate column.
TABLE IV
CONVERSION TABLE-12-in. BRICK OR TILE LENGTH TO RED MARKS ON LINE
| Total Length of 10 brick inches | Multipliers With 3/8 Joint | With 1/4 Joint |
|---|---|---|
| 115 | 505 | |
| 115 3/8 | 502 | |
| 116 1/8 | 500 | |
| 116 5/8 | 497 | |
| 117 3/8 | 494 | |
| 118 1/8 | 492 | |
| 118 3/8 | 489 | |
| 119 1/8 | 487 | |
| 120 | 485 | |
If bond is to be used with Norman or Roman brick, measure the total wall length. This length multiplied by the multiplier will give the number of red marks to count off. Be sure to remember that the black marks are 1/2 of a unit and two units will be laid between the red marks. Then proceed to lay out bond.
When bond is used, either 4-in. header or stretcher units must be placed at the corners so that...