Mason screening questions: brick and block, laying to the line, mortar, flashing and OSHA silica rules

Mason screening questions should establish what the candidate lays (brick, block, stone, or restoration work), whether they can build leads or only run to the line, and how they handle the details that keep water out of a wall. Then cover silica and scaffold safety, because masons cut materials that create respirable silica dust and spend much of their day on scaffolds. Production matters, but a fast mason who builds walls that leak is a callback waiting to happen.

This page covers brick, block and stone masons in commercial and residential construction and restoration. For related trades on the same jobs, see carpenter screening questions and roofer screening questions.

Which mason

Silica and site safety rules

Respirable crystalline silica

OSHA's construction silica standard (29 CFR 1926.1153):

• Sets a permissible exposure limit of 50 micrograms per cubic meter of air as an 8-hour time-weighted average, with an action level of 25.
• Lists common tasks in Table 1, including stationary masonry saws and handheld power saws, with the engineering controls (usually water or dust collection) and respirator requirements; employers that fully implement those controls meet the standard's exposure rules for those tasks.
• Requires a written exposure control plan and a competent person who makes frequent and regular inspections.
• Prohibits dry sweeping or dry brushing, and using compressed air to clean clothing or surfaces, where it could contribute to exposure, unless a safer method is not feasible or, for compressed air, it is used with a ventilation system that captures the dust.
• Requires medical surveillance, at no cost, for employees who must wear a respirator 30 or more days a year.
• Requires training so employees know the health hazards, the tasks that expose them, the controls, and the competent person's identity.

Masonry walls and scaffolds

OSHA requires a limited access zone whenever a masonry wall is being built, on the unscaffolded side, equal to the height of the wall plus four feet and running the length of the wall, and requires walls over eight feet to be braced unless adequately supported (29 CFR 1926.706). Employees working on scaffolds must be trained by a qualified person on the hazards of the scaffold type (29 CFR 1926.454).

Apprenticeship

Many masons train through registered apprenticeships run by union training centers or contractors' associations. Registered programs are approved by the Department of Labor or a State Apprenticeship Agency (Apprenticeship.gov), and employers can verify completion through Verify My Apprenticeship with the person's apprentice number and date of birth, collected only at the verification step.

Knockout questions

Laying and layout questions

1. "Talk me through building a corner lead."
   • Strong answer: lays out the bond dry or checks the layout, sets the first course to the mark, uses a story pole or course gauge, keeps the lead plumb, level and true with the level at every course, racks back, checks the corner square.
   • Red flags: only ever ran to someone else's leads, for a role that needs leads.
2. "How do you run a wall to the line?"
   • Strong answer: line blocks or pins on the leads, keeps the line tight, uses a trig in the middle of long runs, lays to the line without crowding it, checks head joints.
   • Red flags: pushes units into the line.
3. "Which mortar types do you use and when?"
   • Strong answer: follows the specification, knows types such as N and S and why one is chosen over another, mixes consistently, knows retempering limits, and for restoration uses a mortar compatible with the old masonry.
   • Red flags: "Stronger is always better," especially in restoration.
4. "When do you tool the joints?"
   • Strong answer: when the mortar is thumbprint hard, with the joint profile the job specifies, consistently across the wall.
   • Red flags: tools when convenient.

Water management and reinforcement

Restoration questions

• "How deep do you rake out joints before repointing?" Strong: to the depth the specification sets, by hand or with controlled tools and dust collection, without chipping the edges of the units.
• "How do you clean masonry?" Strong: the gentlest effective method first, a test panel, no harsh acids or high pressure on soft brick or stone.

Safety questions

• "How do you cut block or brick on site?" Strong: wet saw or a saw with dust collection, as the silica plan requires, and a respirator when the plan calls for it. Red flag: dry cutting with no controls.
• "How do you clean up at the end of the day?" Strong: wet methods or a HEPA vacuum, no dry sweeping of silica dust.
• "What do you check on the scaffold before you load it?" Strong: inspected by the competent person, planked fully, guardrails, load limits, safe access.
• "What is the limited access zone?" Strong: knows it keeps others away from a new wall that could collapse, and that tall walls are braced.

How mason experience gets overstated

• Tender time counted as laying. Ask what they laid and on which projects.
• Production figures without context. If a candidate quotes how many units a day they lay, record it as their own figure and ask the material, wall type and conditions; do not compare to a benchmark.
• Stone veneer limited to manufactured panels, presented as natural stone. Ask about cutting and fitting.
• Restoration without mortar matching. Ask how they chose the last mortar for an old building.

Scoring

In the submittal, list materials and wall types, years as mason and as tender, apprenticeship and completion date, the projects and building types, and the candidate's lead-building answer in their own words. For questions that probe safety habits more broadly, see interview questions for safety mindset, and for the overall process, the interview guide for construction roles. Ask whether candidates can meet the job's lifting and scaffold work requirements, with or without accommodation, not about past injuries.