Brick Dimensions and Properties

Brick Dimensions and Standard Break Height

• Standard brick dimensions:

  • Height: 2 \frac{1}{4} inches.

  • Depth: 3 \frac{5}{8} inches. The mortar joints for standard brick are typically \frac{3}{8} of an inch, which means that when the brick is turned as a header course, the dimension from the beginning to the edge of the mortar joint will equal to 4 inches.

  • Length: 7 \frac{5}{8} inches. It's \frac{5}{8} inches short of 8 inches so that when you put a mortar joint, it makes an eight inch dimension after completion.

Modularity and CMU

• Three bricks stacked with mortar joints equal the height of a Concrete Masonry Unit (CMU).

• When a block is turned on its side, and two more bricks are stacked with a mortar joint, they line up exactly with the top of the CMU.

• Anchors can be placed in the CMU that reach into the joints, locking the brick veneer to the load-bearing wall.

• A brick, a joint, and another brick equal the length of a CMU.

• Advantage of brick: consistent size, aiding modular construction.

Louie Kahn and Brick

• Louis Kahn: Famous architect from Philadelphia, designed the Salk Institute, worked in India, advocated for understanding materials.

• Kahn's Algorithm: "To express is to drive, and when you want to give something present, you have to consult nature. And there is where design comes in."

• Kahn's Material Philosophy: Asking a brick what it wants, and the brick says, "I like an arch."

History of Brick

• Early construction: Mud was used to join bricks for low walls.

• Stone was initially preferred, but brick became prevalent due to clay availability.

• The hardening effect of fires near mud brick walls led to the development of kilns.

• Medieval period: Stone and brick were commonly used as construction materials.

• 1800s: Transition from load-bearing masonry due to the rise of steel.

The Monadnock Building

• The Monadnock Building: Located in Chicago, an example of tall masonry load-bearing structure.

• Base thickness: Six feet thick to handle the height, tapering as it ascends.

• Limitation: Difficult to construct tall structures with brick masonry.

Shift to Steel and Reinforced Concrete

• Late 1800s: Dominance of masonry declined with the advent of steel.

• Brick became a veneer or aesthetic skin on buildings.

• 20th-century developments: Steel reinforcing (especially high-strength steels) integrated into masonry.

• Brick is used aesthetically rather than as a load-bearing material.

• Development of high-strength mortars and bricks.

• Versatility: Brick can be molded and shaped into various textures and colors.

The Role of Mortar

• Mortar: Adhesive between bricks, major aesthetic component.

• Mortar's Benefits:

  • Cushions masonry units to ensure uniform bearing.

  • Seals joints, preventing water and pest intrusion.

  • Adheres units together.

• Weakest point: The joint is the weakest point in any masonry wall.

Mortar and Aesthetics

• Mortar contributes to the overall aesthetic of the wall.

• Examples:

  • Lighter mortar accentuates the bricks.

  • Raked joints create heavy shadows.

  • Thick mortar joints provide design latitude.

  • Mortar color can match or contrast with the brick.

Frank Lloyd Wright and the Roby House

• Frank Lloyd Wright: Used Roman brick at the Roby House.

• Horizontal joints: Lighter mortar to accentuate the prairie style.

• Vertical joints (head joints): Red mortar to match the brick, creating a thinner visual line.

• The different mortar types, combined with the two colors (horizontal joints using one mortar mix, vertical joints using mix with a red pigment), required an intense level of attention to detail by the Masons.

Ingredients in Cement Lime Mortar

• Portland Cement:

  • Acts as a bonding agent.

  • Composed primarily of calcium silicates.

  • Source: Limestone, marble, and other minerals.

  • Hydraulic cement: Reacts chemically with water, generating heat and creating a bonding agent.

  • Chemical byproduct of adding water to create portland cement: Hydration.

  • Includes lesser quantities of iron compounds.

• Sand:

  • Fine aggregate.

  • Forms the general body of the mortar.

• Hydrated Lime:

  • Made from grinding limestone and creating quicklime.

  • Improves workability:

    • Makes the mortar smooth.

    • Easy to apply with a trowel.

• Water:

  • Kicks off the chemical reaction with the Portland cement.

  • Too much water weakens the mortar; the correct amount is crucial.

Mortar Mix

• Cubic foot of sand: Forms the major body of the mortar.

• Cement: Binds the ingredients together.

• Lime: Enhances workability.

• Minimum water: Needed for the chemical reaction with Portland cement.

Different Mortar Mixes

• Blended Hydraulic Cement: Portland cement mixed with other cementitious materials to decrease environmental impact.

• Environmental Impact:

  • Portland cement has a large carbon footprint due to its energy-intensive production.

  • Reducing Portland cement usage is environmentally and economically beneficial.

• Masonry Cement: Proprietary mix with company-specific ingredients.

• Mortar Cement: Proprietary material, similar to masonry cement.

• Lime Cement: Lime-based mortar with no Portland cement.

Lime-Based Mortar

• Lime-based mortar (Type K): Weakest mortar, used before Portland cement introduction.

• Softer and weaker compared to Portland cement mortars.

• Self-healing property: Can heal cracks with air and water.

• Usage: Almost exclusively for preservation work, rarely for commercial or residential projects.

Mortar Additives

• Pigments: For coloring the mortar.

• Aggregates: Additives to mortar.

• Bond Enhancers: Additives to mortar.

• Cold Weather Admixtures: Used to ensure hydration in cold weather.

• Hot Weather Admixtures: Helps mortar cure at the correct rate in hot climates.

• Water Repellents: Adds resistance to moisture.

• Workability Enhancers: Facilitates spreading and troweling, particularly in high-strength mortars.

Mortar Types

• M (highest strength): High tensile and compressive strength.

  • Use cases:

    • Severe freezing and thawing conditions.

    • Direct contact with the earth.

• S and N: Most commonly used mortars in the US.

  • S Use Cases::

    • Reinforced load-bearing masonry.

    • Exterior veneer subject to high wind forces.

  • N Use Cases:

    • Non-load-bearing masonry.

    • Ideal for veneers.

• O: Interior non-load-bearing masonry or historic masonry restorations.

• K: Historic applications with no Portland cement.

Mixing Mortar

• Recipe Approach:

  • Defined proportions of ingredients.

  • Simpler method for defining mortar requirements.

  • Higher lime content equals lower strength.

  • Higher Portland content equals higher strength.

• Empirical Approach:

  • Custom-designed mix for the project.

  • Testing agency determines exact ingredients.

  • Allows for tweaking ingredients to reduce Portland cement.

  • Cost-effective for large projects.

Compressive Strength of Mortar

• M: 2,500 psi (strongest).

• S: 1,800 psi.

• N: 750 psi.

• O: 350 psi (weakest).

Brick Manufacturing Process

• Material: Natural clays and shales.

• Excavation: Raw materials are excavated, ground, and screened.

• Water Addition: Water is added for plasticity and shaping.

Molding Bricks

• Soft Mud Process:

  • Moist clay pressed into individual molds.

  • Water struck: Molds submerged in water.

  • Sand struck: Sand used to prevent sticking to mold forms.

  • Can be handmade or machine-made.

• Dry Press:

  • Dry clay material, machine-pressed into steel molds at high pressure.

  • Associated with more natural variations.

• Molded bricks are frequently more expensive than extruded bricks.

Extruded Bricks (Stiff Mud Process)

• Process:

  • Moist clay extruded through a die and sliced into individual units.

  • Least expensive molding method.

  • Standard for U.S. production.

• Characteristics:

  • Smooth face and high dimensional uniformity.

• Texturing: Wires or textured surfaces can be used to add variation.

Firing Bricks

• Kiln:

  • Bricks are fired to harden them.

  • Pass through various stages of design and chemical transformation.

• Tunnel Kiln:

  • A hot tunnel in which the product moves continuously through.

• Periodic Kiln:

  • Batches are loaded and fired (e.g., beehive kiln).
    Clinkers: Bricks near the flame that become hard, twisted, and purplish, sometimes used by designers for their unique appearance.

Brick Dimensions and CMU

• Length: 7 \frac{5}{8} inches.

• Height of three stacked bricks: Equals the height of a CMU (Concrete Masonry Unit).

• Depth: 3 \frac{5}{8} inches.

• 12 Bricks: Occupy the same volume as a CMU.

• CMU Dimensions (standard 8-inch):

  • 7 \frac{5}{8} inches.

  • 7 \frac{5}{8} inches.

  • 15 \frac{5}{8} across face.

Hollow Bricks

• Holes:

  • Allow for reinforcement.

  • Reduce weight.

• Clay:

  • Strong in compression but weak in tension.

• Steel Reinforcement: Can be added for strength.

Brick Shapes and Design

• Molding: Clay allows for molding into various shapes.

• Examples: Bullnose edges, beads, stamped shapes.

Classifications of Brick

• Solid Bricks: At least 75% solid.

• Hollow Bricks: Up to 60% void, larger size, allows for more reinforcing.

Reinforcing Hollow Bricks

• Steel: Reinforcing bars placed in cores and filled with grout.

Face Brick vs. Building Brick

• Face Brick: Appearance-graded brick.

• Building Brick: Less aesthetically important, used as a backup or common brick.

Brick Grading

• Brick Grading and Weathering

• SW (Severe Weathering):

  • For areas with severe weathering conditions.
    Note: Be able to specify, give a location of the US, whether you will need to use brick that qualifies/graded as SW (severe weathering), MW (moderate weathering), or NW (non-weathering) brick.

Brick Type

• FBX: very little variation, really consistent very little distortion, minimum chip edge, dimensionally consistent.

• FBS: general purpose brick, precise for a general purpose.

• FBA: hand molded bricks, non uniform, might have different colors, might have different shapes.

Terminology

• Terminology For Brick Wall

• Course: The horizontal line of brick.

• Bed Joint: Horizontal mortar joint.

• Head Joint: vertical mortar joint.

• Two wide brick wall with header bricks and stretcher bricks, The headers turning sideways to lock bricks behind it in place.

• Why: the columns of bricks, a brick here and then a brick right behind it.

• The joint in the center between the two wides is know as the collar joint.

Other Terms

• Weep hole

• Water stop

• Underpinning

• Trowel

• Top plate

• Sole plate

• Sil sealer and sil plate

• Planesong, order sawn, ring joist, riser, framing plan

• Grade (term used twice):

  • Ground level (above or below grade).

  • Material grade (e.g., builder-grade wood).

• Trout [sic]: Trowel is spelled T-R-O-W-E-L