Reading Masonry Details: Bond, Wall Types, Reinforcement & Joints

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Here's one that matters more than its name lets on — Reading Masonry Details: Bond, Wall Types, Reinforcement & Joints. If you remember one thing, make it this: The masonry details on the drawings — bond pattern, wall type, reinforcing, lintels, movement joints, and moisture management — come from TMS 402/602 and the building code, and a mason who can read them builds a wall that stands up and stays dry. Do this right and the inspector, the engineer, and the mason are building the same wall.

The codes

TMS 402/602 — Building Code Requirements and Specification for Masonry Structures, from The Masonry Society — is the design code (402) and construction specification (602). The International Building Code adopts it by reference in Chapter 21; the International Residential Code carries simplified provisions for houses (Chapters 6, 7, and 10).

Bond patterns

Running bond — each unit overlapping the one below by half — is the structural default and the most common pattern. Stack bond is a look, not a bond, and TMS 402 requires horizontal reinforcement in it. Common, Flemish, and English bonds mix header and stretcher courses for appearance.

Wall types

• Single-wythe CMU — one thickness of block, usually reinforced and grouted.
• Cavity wall — an outer wythe of brick, an air space of about 2 inches, and a backup wythe of block, tied together.
• Anchored veneer — brick or stone tied to a wood or steel stud backup over sheathing and a water-resistive barrier, with at least a 1-inch air space.
• Adhered veneer — thin brick or manufactured stone bonded with mortar over lath and a drainage plane.

Reinforced masonry and lintels

A reinforced CMU wall has vertical bars in grouted cells at corners, jambs, ends, and regular spacing (often 48 inches), bond beams at the top, at floor lines, and over openings, and often joint reinforcement in the bed joints. Low-lift grouting fills cells as the wall rises; high-lift grouting fills tall pours afterward and requires cleanouts when the pour exceeds 5 feet 4 inches (TMS 602). Every opening needs a lintel — steel angle, reinforced block, or precast — with at least 4 inches of bearing at each end and flashing and weeps on top.

Movement joints

Concrete block shrinks as it dries, so CMU walls get control joints — vertical breaks with a shear key and sealant — commonly 20 to 25 feet apart and beside openings. Clay brick expands as it absorbs moisture, so brick walls get expansion joints — compressible filler and sealant, nothing solid in the joint. A movement joint filled with mortar is no joint at all.

Moisture management

The details show through-wall flashing at the base, sills, and heads, with end dams and drip edges; weep holes at 33 inches maximum; a clear air space; the water-resistive barrier on the backup; and tie spacing (the IRC calls for ties at 24 inches maximum each way, one per 2.67 square feet).

Going Deeper (Intermediate)

The structural drawings carry wall sections, reinforcing schedules, and the lintel schedule; the architectural drawings carry bond, coursing, joint profile, and flashing. Joint profile matters for weather: concave and V-joints compress the mortar and shed water; raked and struck joints hold water and belong indoors.

Special inspection under IBC Chapter 17 applies to most structural masonry: an inspector verifies mortar, reinforcing, and grout placement under a Level B or C quality assurance program from TMS 602, so cells must be open for inspection before grouting.

Advanced / Pro-Level

Pros read a detail and see the loads and the water at once. They know that brick set tight under a shelf angle with no horizontal expansion joint will crush as the wall grows. They coordinate embedded items before the wall goes up, because cutting them in afterward wrecks the grout and the fire rating.

Practice Challenge

A detail shows brick veneer over wood framing with no flashing or weeps at the base and the brick mortared tight to the underside of a steel lintel. Name three problems. (Answer: water in the cavity has no exit and will wet the sill and framing; the lintel needs flashing with end dams and weeps above it; and brick set tight to the lintel leaves no room for movement.)

In Practice

A mason who lays out control joints from the drawings before the first course has a wall with no cracks. A mason who puts them where they land has a diagonal crack from every window corner.

Common Mistakes to Avoid

• Filling a movement joint with mortar
• Omitting end dams and weeps at lintels and sills
• Grouting cells before the inspector sees the reinforcing
• Stack bond without the required horizontal reinforcement

Takeaway: The masonry details on the drawings — bond pattern, wall type, reinforcing, lintels, movement joints, and moisture management — come from TMS 402/602 and the building code, and a mason who can read them builds a wall that stands up and stays dry.

Educational overview only — not hands-on masonry instruction, a safety program, or a substitute for training under a qualified mason. Follow OSHA 29 CFR 1926 (including Subpart L, 1926.706, and 1926.1153), TMS 402/602 and the adopted building code, your state's contractor licensing rules, the project specifications, and your employer's procedures for your work.