2.1.3 Movement Joints

• Movement Joint: An all-encompassing term that can be defined more specifically as a Control Joint, Expansion Joint, Isolation Joint, Building Movement Joint, etc.
• Control Joint: Control Joints allow for movement in structural masonry elements due to contraction in the material. Control Joints require design and detailing by a structural engineer to ensure stability of the structural masonry elements.
• Veneer Expansion Joint: Expansion Joints allow for movement in masonry veneer elements due to moisture expansion and thermal moisture expansion and contraction in the material. Expansion Joints require design and detailing to ensure stability of the masonry veneer elements.
• Isolation Joint: Isolation Joints are provided where the bearing condition for the masonry elements change (e.g. Isolation Joints are provided at the edge of brick veneer bearing on a lintel). Isolation Joints can be Control Joints or Expansion Joints and should be detailed as such to ensure stability of the masonry elements.
• Building Expansion Joint: A Building Expansion Joint allows for movement of an entire wall assembly. Building Expansion Joints combine veneer Expansion Joints and structural Control Joints. Building Expansion Joints penetrate the entire depth of the wall and require design and detailing by a structural engineer to ensure stability of the masonry wall elements.

NOTE: Control Joints and Expansion Joints are NOT synonymous, as they should be clearly identified by definition on the Drawings based upon design intent.

• Vertical Control Joint: Control Joints relieve shrinkage stress at a predetermined location to mitigate the risk of cracking. Vertical Control Joints in CMU typically consist of a minimum 3/8 inch wide vertical gap through a CMU wythe. The Control Joint may be filled with an elastic material. Vertical Control Joints will change in size as the masonry construction expands and contracts throughout its life. Control Joints must be located by the structural engineer to ensure the stability of the masonry wall is not affected. Control Joints need to be clear of mortar for installation of backer rod and sealant or the elastic joint filler.
• Vertical Veneer Expansion Joint: Expansion Joints prevent cracking by separating brick veneer in segments. The segmentation of the brick veneer reduces the cumulative effect of movements caused by changes in temperature, moisture expansion, elastic deformation, settlement and creep. Expansion Joints are formed by leaving a continuous unobstructed opening through veneer wythe that may be filled with a highly compressible material. Expansion Joints need to be clear of mortar for the full depth of the masonry wythe in order to allow for independent movement and installation of backer rod and sealant. Compressible filler accessories should also be installed to keep the joint free of mortar for the full height and depth of the Expansion Joint.

Buildings should be evaluated holistically by the design team to optimize the proper locations of Masonry Movement Joints.

The following are empirical guidelines for locating Masonry Movement Joints
(Based upon the Brick Industry Association (BIA) Technical Notes 18A (May 2019):

Vertical Expansion Joint Locations in Clay Brick Veneer (Based on empirical method):

• For brickwork without openings (Spacing frequency: 25’-0” o.c., maximum)
• For brickwork with multiple openings, provide symmetrical placement of expansion joints (Reduced spacing frequency: 20’-0” maximum)
• When spacing between vertical expansion Joints in parapets is more than 15’-0”, make expansion joints wider or place additional expansion joints halfway between full-height expansion joints.
• Typically, place vertical expansion joints as follows:
  • At or near corners
  • At offsets and setbacks
  • At wall intersections
  • At changes in wall height
  • Where wall backing system changes
  • Where support or brick veneer changes
  • Where wall function or climatic exposure changes
  • Expansion joint locations shall be based upon the masonry module of the building
  • Extend vertical expansion joints to top of brickwork, including parapets

Horizontal Expansion Joint Locations in Clay Brick Veneer:

• Locate immediately below shelf angles
• Minimum 1⁄4” space with compressible material typically recommended below shelf angle to prevent mortar collection in the movement joint that would restrain moment.
• Size of movement joint is coordinated between the AOR and SEOR to accommodate the differential movement between veneer and structure.
• Dimension size of Horizontal Movement Joints on drawings.

Shelf Angle Locations / Vertical Height Limitations:

• At clay brick veneer with metal stud backing (Prescriptive requirements for shelf angle location)/Masonry Code Section 12.2.2.7.1 references BIA Tech Notes 28B (2005)
  • 30’-0” maximum veneer height restriction
  • 38’-0” maximum height to gable
  • Required at every story above 30’-0”
    • However, it is not uncommon to follow the Alternate Design Method for optimizing shelf angle location.
    • Alternate Design for shelf angles beyond 30 feet in height is possible (refer to TMS 402 Masonry Code Section 12.2.1). The International Masonry Institute is available for consultation and guidance if needed.
• At brick veneer with CMU backing (Prescriptive requirements)/BIA Tech Note 18A-2019.
  • No veneer height restriction
  • 50’-0” maximum recommended brick veneer height provided that:
    • The building is detailed appropriately for differential movement
    • The moisture drainage system is designed and constructed properly, typical every other floor
• Alternative Design for shelf angles beyond 30 feet in height is possible (refer to TMS 402 Masonry Code Section 12.2.1)

Clay Brick Expansion Joint and CMU Control Joint widths should be dimensioned on the project drawings. The following joint widths are recommended minimums:

• 1/2 inch minimum is common for clay brick expansion joint width for various technical reasons to accommodate the irreversible moisture expansion of the brick.
• 3/8 inch minimum CMU control joint widths

Expansion joint sealants shall meet the following requirements:

• Comply with ASTM C920, Grade NS, Use M
• Minimum compressibility of class 50 silicone sealant required. Use class 35 urethane sealant for wood substrate or when painting is necessary.
• Consult sealant manufacturer’s literature for guidance regarding use of primer and backing material

Cementitious Veneer Bond Breaks:

• Bond break materials such as backer rods or bond breaker tape are required at all movement joints in order to maintain proper sealant profiles and prevent three-sided adhesion. Refer to BIA and NCMA industry standard details for more informational on detailing practices.

Additional Resources

Additional Resources for the design of Masonry Movement Joints:

• International Masonry Institute

Additional National Concrete Masonry Association (NCMA) technical guidelines for the Design of Movement Joints:

• NCMA TEK 10-2D / Control Joints for Concrete Masonry Walls - Empirical Method
• CMU structural masonry, non-load bearing CMU partition walls Movement Joint guidelines NCMA TEK 10-2D uses the Empirical Method (more common).
• NCMA TEK 10-3 / Control Joints for Concrete Masonry Walls – Alternative Engineered method
• Uses the Alternative Engineered Method. Can solves many challenges in a project and can have possible cost benefits.
• NCMA TEK 10-01A / Crack Control in Concrete Masonry Walls
• NCMA TEK 10-4 / Crack Control for Concrete Brick and other Concrete Masonry Veneers

Additional Brick Industry Association (BIA) Technical Notes for the Design of Movement Joints:

• BIA Tech Note 18A-2019 / Accommodating Expansion of Brickwork
• BIA Tech Note 28B-2005 / Brick Veneer /Steel Studs

Additional Resources for the design of Masonry Movement Joints:

• International Masonry Institute

Additional National Concrete Masonry Association (NCMA) technical guidelines for the Design of Movement Joints:

• NCMA TEK 10-2D / Control Joints for Concrete Masonry Walls - Empirical Method
  - CMU structural masonry, non-load bearing CMU partition walls Movement Joint guidelines NCMA TEK 10-2D uses the Empirical Method (more common).
• NCMA TEK 10-3 / Control Joints for Concrete Masonry Walls – Alternative Engineered method
  - Uses the Alternative Engineered Method. Can solves many challenges in a project and can have possible cost benefits.
• NCMA TEK 10-01A / Crack Control in Concrete Masonry Walls
• NCMA TEK 10-4 / Crack Control for Concrete Brick and other Concrete Masonry Veneers

Additional Brick Industry Association (BIA) Technical Notes for the Design of Movement Joints:

• BIA Tech Note 18A-2019 / Accommodating Expansion of Brickwork
• BIA Tech Note 28B-2005 / Brick Veneer /Steel Studs