NCCER Masonry key terms

A single continuous horizontal layer of masonry units laid in mortar. Courses stack to build a wall, and their height and alignment control the overall dimensions and levelness of the finished work.

A continuous vertical layer of masonry, one unit thick, that forms part of a wall. A wall may be a single wythe or several tied together, and the term distinguishes layers from courses.

The horizontal mortar layer on which masonry units are laid. Its thickness and fullness transfer compressive load between courses and help seal the wall against air and water penetration.

The vertical mortar joint between the ends of adjacent masonry units in the same course. It bonds units together and, when tooled, helps shed water from the wall face.

A workable mixture of cementitious material, sand, and water that bonds masonry units into a single structural element. Type and consistency affect bond strength, flexibility, and weather resistance.

A classification (M, S, N, O, or K) that sets the proportions of cementitious materials and lime in mortar. Higher-strength types suit heavy load and severe exposure; lower types suit interior or soft-unit work.

A cementitious ingredient in mortar that improves workability, water retention, and flexibility. It lets mortar accommodate slight movement and helps it bond to absorbent units without drying out too fast.

Finishing the mortar joint with a jointer or trowel while the mortar is thumbprint hard. Proper tooling compresses the mortar, seals the joint surface, and forms a profile that drains water away.

A bond pattern in which each unit overlaps the units below by half a unit, so head joints are offset from course to course. It is the most common pattern for walls and provides good strength.

The arrangement of masonry units in a wall so that vertical joints are offset and the units interlock. Bond patterns distribute load, control cracking locations, and give the wall its visual character.

A masonry unit laid lengthwise along the wall face, showing its long side. Stretchers make up most of a wall's face area and alternate with other units to create the chosen bond pattern.

A masonry unit laid across the wall thickness so its end shows on the face. Headers tie multiple wythes together and are placed at intervals in bonds such as English or Flemish bond.

A wall built with two separate wythes and an air space between them. The cavity stops water from crossing to the interior, and wall ties hold the wythes together while flashing drains the space.

A metal fastener embedded in both wythes of a cavity wall to tie them together. Ties must be spaced and installed per code so the wall acts as one assembly and resists wind and seismic loads.

Impervious material installed at wall bases, openings, and roof intersections to direct water out of the wall. Correct lapping and weep holes let moisture escape instead of being trapped inside the assembly.

A small opening left in the mortar at the base of a cavity wall or above flashing so water can drain out. Weep holes must stay clear to prevent moisture from collecting behind the masonry.

A brick, block, or stone piece sized for laying by hand with mortar. Units are specified by material, dimensions, and compressive strength, and those properties govern what the wall can carry.

A hollow or solid block made of portland cement, aggregate, and water, often called CMU. Standard nominal sizes and hollow cores allow grout and rebar to be placed inside the block for reinforced walls.

A high-slump cementitious mixture poured into masonry cores or cavities. It fills voids around reinforcement, bonds the assembly together, and adds mass and compressive capacity to reinforced masonry.

Steel reinforcement placed in grouted cores or bond beams of masonry walls. It provides tensile strength that plain masonry lacks, allowing walls to resist bending, shear, and seismic forces.

A horizontal beam formed by grouting a continuous course of block around reinforcement. Bond beams stiffen the wall, distribute loads over openings, and tie the structure to floors and roofs.

A horizontal member that carries masonry above a door, window, or other opening. It transfers the load to the surrounding wall and must be sized and bearing properly set to avoid cracking.

A threaded fastener set into masonry or concrete to attach framing, sills, or structural members. Placement, embedment, and torque must match the approved drawings and code requirements.

A power saw with an abrasive or diamond blade used to cut brick, block, and stone to size. Correct blade choice, water cooling, and clamping produce clean cuts and reduce dust and blade wear.

Using a hammer or chisel to break away small amounts of masonry for fitting, corbeling, or removing damaged material. Controlled chipping avoids overbreak and preserves the strength and appearance of adjacent units.

The mason's primary hand tool, a flat steel blade with a handle used to pick up, spread, and shape mortar. Blade size and handle grip affect how evenly mortar is placed on the bed and unit ends.

A taut cord stretched along a wall to guide the height and face alignment of each course. It is checked and moved as work rises so the wall stays straight, level, and plumb.

Exactly vertical. Masons check plumb on corners and wall faces with a spirit level or plumb bob so the wall does not lean, which would weaken it and cause misalignment above.

Exactly horizontal, or the tool used to check it. Courses must be laid level so load is distributed evenly and openings, sills, and bond beams line up as detailed on the drawings.

A marked board showing course heights and key elevations, set at the work area as a reference. It lets masons keep coursing consistent and verify dimensions without measuring every course.

A mortar bed spread across the full width of a unit's bearing surface, as opposed to a face shell or spot bed. Full bedding is required where the specification demands complete joint contact.

Applying mortar to the vertical end of a unit before it is pushed into place, forming the head joint. Correct buttering fills the joint fully and produces a tight, water-resistant bond.

Cutting out deteriorated mortar to a uniform depth and refilling the joint with new mortar. Done correctly, it restores weather resistance and appearance without damaging the masonry units.

A temporary elevated platform that supports workers, tools, and materials at height. It must be erected, plumbed, guarded, and inspected per safety rules before any masonry work begins.

Systems and practices that prevent workers from falling from scaffolds, walls, or openings. It includes guardrails, personal fall arrest, and safe access, and is required above trigger heights set by safety standards.

Gear worn to reduce injury risk, such as hard hats, safety glasses, gloves, hearing protection, and respirators. Task hazards like cutting dust and overhead loads determine which equipment is required.

Fine airborne particles released when cutting, grinding, or chipping concrete and masonry. It causes serious lung disease, so wet cutting, ventilation, and respirators are used to control exposure.