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newSchoolWorks.com › VoTechWorks › Building & Construction › Masonry › Brick Masonry: Materials, Bonds, and Coursed Wall Construction › Lesson 5
BLD-MASO04-02 · Lesson 5 · 12 clock hours · demo

Layout Tools and Establishing the First Course

Objective. The learner will use a story pole, mason's level, corner blocks, and line pins to dry-bond a full first course of brick to a chalk-line layout and confirm it is level and square before mortaring.

⚠ Pending professional review

This lesson, its worked examples and its practice questions has not yet been verified by a licensed professional engineer or master tradesperson or by a certification or approval body. It is a study draft and may contain errors. Do not use it as instructions for work on a job site or on live equipment. Always follow your instructor, your supervising professional, and current official references and regulations.

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Why the First Course Controls Everything

In brick masonry, the first course is the foundation of every course that follows. If it is not level, not square, and not spaced correctly, errors compound with every added course. A wall that starts 1/4 inch out of level may be nearly an inch out by the time it reaches window-sill height. Getting the first course right — before a single trowel of mortar is spread — is one of the most important skills a mason develops.

Snapping the Layout Lines

Begin by locating the wall's position on the slab or footing. Use a tape measure to mark the two corners of the wall face at each end. Stretch a chalk line between the marks, pull it taut, lift it about an inch, and release it cleanly to snap a straight reference line on the substrate. For a rectangular layout, snap all four sides and verify the corners are square by measuring both diagonals — a true rectangle has equal diagonals. The 3-4-5 triangle method also works: mark 3 feet on one leg, 4 feet on the other, and the hypotenuse should measure exactly 5 feet for a 90-degree corner.

Always wear safety glasses when snapping chalk lines. Chalk dust can irritate eyes, and the line can snap back. Keep bystanders back from the work area.

Dry-Bonding the First Course

Dry-bonding means placing bricks in their final position without mortar to check layout and spacing before committing to mortar. Start by setting a corner brick at each corner of the chalk-line intersection, aligning the brick face precisely with the chalk line. Do not let the brick cover the line — the line represents the finished wall face.

Once the corner bricks are set, stretch a mason's string line between the two corner bricks, using corner blocks or line pins to hold it at the exact face and top of the brick. The string line guides all intermediate bricks. Place bricks along the string one by one, leaving a consistent gap between each brick for the head joint. For standard modular brick, the nominal head joint is 3/8 inch. Use a gauge rod to check spacing consistently — do not rely on eye judgment alone.

Work from both corners toward the middle. The final brick in the center — sometimes called the closure brick — should fit the remaining space with the same 3/8-inch head joints on each side. If it does not fit, small adjustments are distributed evenly across the course by slightly opening or closing head-joint spacing, keeping all joints within acceptable tolerance.

Using the Story Pole

A story pole (also called a course pole) is a straight piece of lumber, typically a 1×2, marked with the height of each course. For standard modular brick, each course consists of one brick plus one mortar bed joint. The standard modular unit is nominally 2-2/3 inches tall, and with a 3/8-inch bed joint the combined course height is 4 inches — the 4-inch module. Mark the story pole starting at 0, then at 4 inches, 8 inches, 12 inches, and so on through the planned number of courses.

Holding the story pole vertically at a corner lead lets the mason transfer exact course heights to the wall without measuring each course individually. All corner leads on the same wall are built to match the same story pole, so string lines pulled between them will be level at every course.

Checking Level and Square

After dry-bonding, place the 4-foot mason's level along the top of the course. The bubble must rest centered in the vial for the course to be level. Check the course at multiple points, not just at one end. For shorter sections, the 2-foot torpedo level is useful in tight spaces.

To confirm individual bricks are not rocking or sitting high, press each brick firmly and observe whether adjacent bricks shift. All bricks should rest flat on the substrate. Any high spots must be identified before mortaring — grinding or shimming is not acceptable practice for finished masonry.

The standard tolerance accepted by instructors in this program — and typical of field practice — is level within 1/8 inch across the full run and head-joint spacing within 1/4 inch of nominal.

Safety Points for This Lesson

From Dry-Bond to Mortared Coursing

Once the dry-bond course passes the level and spacing check, the instructor will sign off and you may proceed to mortared coursing in the next lesson. At that point the dry-bond bricks are removed in order, mortar is spread and furrowed on the substrate, and each brick is reset to the string line. The discipline developed in dry-bonding — consistent spacing, reading the level, trusting the string — carries directly into mortared work.

Key terms9

Dry-bondPlacing bricks in their intended position without mortar to verify layout, spacing, and level before mortar is applied.
Story pole (course pole)A straight length of lumber marked at each course interval — typically 4 inches for standard modular brick — used to transfer consistent course heights to corner leads.
Gauge rodA tool, often a marked stick or the back of a folding rule, used to check that head-joint and bed-joint spacing is uniform and at the correct nominal dimension.
Head jointThe vertical mortar joint between the ends of bricks in the same course; the standard nominal thickness for modular brick is 3/8 inch.
Mason's string lineA taut line stretched between corner leads or corner blocks to guide the alignment and height of intermediate bricks in a course.
Corner blocks (trig blocks)L-shaped plastic or metal clips that grip the corner of a brick to hold the mason's string line at the correct height and face alignment without nails or pins.
Line pinsSteel pins driven into mortar joints at the corners to anchor the mason's string line when corner blocks cannot be used.
4-inch moduleThe standard vertical planning unit in masonry — one course of standard modular brick (approximately 2-5/8 inches tall) plus one 3/8-inch bed joint equals 4 inches total course height.
3-4-5 triangle methodA field method for confirming a 90-degree corner by measuring 3 feet on one leg, 4 feet on the other, and verifying the diagonal measures exactly 5 feet.

Worked examples4

1. A mason is dry-bonding a first course that is 4 feet (48 inches) long. Standard modular bricks are 7-5/8 inches long with 3/8-inch head joints. How many bricks fit in a 48-inch run, and what is the total length of that arrangement?
  1. Find the nominal unit length: 7-5/8 in (brick) + 3/8 in (head joint) = 8 inches per unit.
  2. Divide the run length by the nominal unit length: 48 in ÷ 8 in = 6 units.
  3. A run of 6 bricks has 5 interior head joints (joints between bricks) plus the two end bricks sit at the corners where a head joint is not counted at the wall ends — but to fill a 48-inch run cleanly, use 6 bricks: 6 × 7-5/8 in = 45-3/4 in of brick + 5 × 3/8 in = 1-7/8 in of joints = 47-5/8 in total.
  4. The 48-inch run is not evenly divisible with 5 joints: 47-5/8 in ≠ 48 in. Adjust by spreading the extra 3/8 inch across the 5 head joints: 3/8 in ÷ 5 = 3/40 in extra per joint ≈ a negligible amount, well within tolerance. The mason accepts 6 bricks with 5 joints at approximately 3/8 inch each.
Answer: 6 bricks fit in the 48-inch run. The nominal layout works out to 47-5/8 inches with 5 joints at exactly 3/8 inch; the slight difference is distributed across joints and falls well within the 1/4-inch spacing tolerance.
2. A learner is marking a story pole for 6 courses of standard modular brick at the 4-inch module. What mark (measured from the bottom of the pole) represents the top of the sixth course?
  1. Each course height = 1 brick + 1 bed joint = 4 inches at the standard modular module.
  2. Multiply: 6 courses × 4 inches per course = 24 inches.
  3. Mark the pole at 4 in, 8 in, 12 in, 16 in, 20 in, and 24 in from the bottom reference point.
Answer: The top of the sixth course is at the 24-inch mark on the story pole.
3. A mason checks the diagonal measurements of a 4-foot × 4-foot chalk-line layout to verify squareness. What should both diagonals measure, and how is the 3-4-5 check applied to one corner?
  1. For a square with sides of 4 feet, calculate the diagonal using the Pythagorean theorem: diagonal = √(4² + 4²) = √(16 + 16) = √32 ≈ 5 feet 7-1/16 inches (approximately 67.1 inches). Both diagonals must match this value — if they are equal, the rectangle is square.
  2. To apply the 3-4-5 check at one corner: from the corner point, measure exactly 3 feet along one chalk line and mark it. Then measure exactly 4 feet along the adjacent chalk line and mark it.
  3. Measure the distance between the two marks. If the corner is a true 90-degree angle, that distance must equal exactly 5 feet. If it does not, adjust the chalk lines until all three measurements satisfy the 3-4-5 relationship.
Answer: Both diagonals of a 4×4-foot square should measure approximately 5 feet 7 inches (√32 ft). At each corner, a 3-4-5 triangle check confirms the 90-degree angle when the hypotenuse equals exactly 5 feet.
4. After dry-bonding a 10-brick first course, a learner places a 4-foot mason's level across the run. One end reads 1/4 inch high relative to the other end. Is this within the program's acceptance tolerance, and what should the learner do?
  1. The program tolerance for level is within 1/8 inch across the run.
  2. Compare the measured deviation (1/4 inch) to the tolerance (1/8 inch): 1/4 inch = 2/8 inch, which exceeds the 1/8-inch limit.
  3. The course fails the level check. The learner must identify which brick or bricks are creating the high spot, remove those bricks, address the substrate irregularity (remove any debris or high spots on the slab), and re-lay the dry-bond course.
  4. Re-check with the level after correction. Do not advance to mortared coursing until the level reading is within 1/8 inch.
Answer: 1/4 inch exceeds the 1/8-inch tolerance. The course fails, and the learner must correct and re-check before proceeding.

The math in this lesson2

Learners count 7-5/8 in bricks with 3/8 in joints in 48 in, mark 4 in course modules, and check a 4×4 layout diagonal.
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Brush up in the math halls at newSchoolWorks.com:
In class: Instructor demonstration on the lab floor: snap chalk lines for a 4-foot × 4-foot square, set corner bricks, run mason's string line, and dry-bond intermediate bricks checking head-joint spacing with a gauge rod; learners observe then replicate the sequence step by step. · Timed individual drill: each learner is given a marked slab section and must dry-bond a 10-brick first course with correct spacing within 20 minutes, then check with a level and report the reading; errors are corrected and the drill is repeated. · Paired exercise using a story pole: learners mark a story pole for six courses of standard modular brick at the 4-inch module, compare poles, and discuss how the pole transfers to corner leads.
Materials: Mason's chalk line and chalk, 4-foot mason's level, 2-foot torpedo level, corner blocks, line pins, mason's string line, gauge rod, story poles (shop-made 1×2 lumber), tape measure, dry brick supply, marked concrete slab sections in lab
Check: Instructor measures completed dry-bond first course for level (within 1/8 inch across the run) and equal head-joint spacing (within 1/4 inch of nominal); both criteria must be met before the learner advances to mortared coursing.

Practice check8

Answer each question, then check it. Nothing is recorded; this is your own practice.

Tools, Materials, and Work Practices
1. What is the primary purpose of dry-bonding the first course before spreading mortar?
Masonry Math and Layout
2. For standard modular brick laid at the 4-inch module, what is the combined height of one brick plus one bed joint?
OSHA Safety and Health
3. A mason snaps a chalk line on a concrete slab. Which personal protective equipment is most important to wear during this task?
Masonry Math and Layout
4. When using the 3-4-5 triangle method to check a corner, a mason measures 3 feet along one chalk line and 4 feet along the adjacent chalk line. The measured hypotenuse is 4 feet 9 inches. What does this indicate?
Tools, Materials, and Work Practices
5. What function do corner blocks (trig blocks) serve when running a mason's string line?
Masonry Math and Layout
6. A learner is marking a story pole for 8 courses of standard modular brick at the 4-inch module. At what height should the mark for the top of the fourth course appear?
Quality Control and Tolerances
7. After dry-bonding, a learner checks level across a 10-brick run and finds one end is 3/16 inch higher than the other. According to the program's acceptance standard, what should happen next?
Masonry Math and Layout
8. Why is it important to check diagonal measurements in addition to side lengths when establishing a rectangular chalk-line layout?
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