Accommodating Expansion of Brickwork Abstract

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Accommodating Expansion

of Brickwork


 Expansion joints are used in brickwork to accommodate movement and to avoid cracking. This Technical Note 

describes typical movement joints used in building construction and gives guidance regarding their placement. The theory and 

rationale for the guidelines are presented. Examples are given showing proper placement of expansion joints to avoid cracking 

of brickwork and methods to improve the aesthetic impact of expansion joints. Also included is information about bond breaks, 

bond beams and flexible anchorage.

Key Words:

 differential movement, expansion joints, flexible anchorage, movement, sealants.



 on Brick Construction




1850 Centennial Park Drive, Reston, Virginia 20191 

| | 


Vertical Expansion Joints in Brick Veneer:

• For brickwork without openings, space no more than 25 ft 

(7.6 m) o.c.

• For brickwork with multiple openings, consider symmetrical 

placement of expansion joints and reduced spacing of no 

more than 20 ft (6.1 m) o.c.

• When spacing between vertical expansion joints in para-

pets is more than 15 ft (4.6 m), make expansion joints 

wider or place additional expansion joints halfway between 

full-height expansion joints

• Place 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 of brick veneer changes

  - where wall function or climatic exposure changes

• Extend to top of brickwork, including parapets 

Horizontal Expansion Joints in Brick Veneer:

• Locate immediately below shelf angles

• Minimum ¼ in. (6.4 mm) space or compressible material 

recommended below shelf angle

• For brick infill, place between the top of brickwork and 

structural frame

Brickwork Without Shelf Angles:

• Accommodate brickwork movement by:

  - placing expansion joints around elements that are rigidly    

    attached to the frame and project into the veneer, such 

    as windows and door frames

  - installing metal caps or copings that allow independent  

  vertical movement of wythes

  - installing jamb receptors that allow independent  


  movement between the brick and window frame

  - installing adjustable anchors or ties

Expansion Joint Sealants:

• Comply with ASTM C 920, Grade NS, Use M

• Class 50 minimum extensibility recommended; Class 25 


• Consult sealant manufacturer’s literature for guidance 

regarding use of primer and backing materials 

Bond Breaks:

• Use building paper or flashing to separate brickwork from 

dissimilar materials, foundations and slabs

Loadbearing Masonry:

• Use reinforcement to accommodate stress concentrations, 

particularly in parapets, at applied loading points and 

around openings

• Consider effect of vertical expansion joints on brickwork 


© 2006 Brick Industry Association, Reston, Virginia 

Page 1 of 11


A system of movement joints is necessary to accommodate the changes in volume that all building materials 

experience. Failure to permit the movements caused by these changes may result in cracks in brickwork, as 

discussed in Technical Note 18. The type, size and placement of movement joints are critical to the proper 

performance of a building. This Technical Note defines the types of movement joints and discusses the proper 

design of expansion joints within brickwork. Details of expansion joints are provided for loadbearing and 

nonloadbearing applications. While most examples are for commercial structures, movement joints, although rare, 

also must be considered for residential structures.


The primary type of movement joint used in brick construction is the expansion joint. Other types of movement 

joints in buildings that may be needed include control joints, building expansion joints and construction joints. Each 

of these is designed to perform a specific task, and they should not be used interchangeably. |


Brick Industry Association








Accommodating Expansion of Brickwork 



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An expansion joint separates brick masonry into segments to prevent cracking caused by changes in 

temperature, moisture expansion, elastic deformation, settlement and creep. Expansion joints may be horizontal 

or vertical. The joints are formed by leaving a continuous unobstructed opening through the brick wythe that may 

be filled with a highly compressible material. This allows the joints to partially close as the brickwork expands. 

Expansion joints must be located so that the structural integrity of the brickwork is not compromised.

control joint determines the location of cracks in concrete or concrete masonry construction due to volume 

changes resulting from shrinkage. It creates a plane of weakness that, in conjunction with reinforcement or joint 

reinforcement, causes cracks to occur at a predetermined location. A control joint is usually a vertical gap through 

the concrete or concrete masonry wythe and may be filled with inelastic materials. A control joint will tend to 

open rather than close. Control joints must be located so that the structural integrity of the concrete or concrete 

masonry is not affected.

building expansion joint is used to separate a building into discrete sections so that stresses developed in one 

section will not affect the integrity of the entire structure. The building expansion joint is a through-the-building joint 

and is typically wider than an expansion or control joint.

construction joint (cold joint) occurs primarily in concrete construction when construction work is interrupted. 

Construction joints should be located where they will least impair the strength of the structure.




Although the primary purpose of expansion joints is to 

accommodate expansive movement, the joint also must resist 

water penetration and air infiltration. A premolded foam or 

neoprene pad that extends through the full wythe thickness 

aids in keeping mortar or other debris from clogging the joint 

and increases water penetration resistance. Fiberboard and 

similar materials are not suitable for this purpose because 

they are not as compressible.

Mortar, ties or wire reinforcement should not extend into 

or bridge the expansion joint. If this occurs, movement will 

be restricted and the expansion joint will not perform as 

intended. Expansion joints should be formed as the wall is 

built, as shown in 

Photo 1

. However, vertical expansion joints 

may be cut into existing brickwork as a remedial action.


Sealants are used on the exterior side of expansion joints to prevent water and air penetration. Many different 

types of sealants are available, although those that exhibit the highest expansion and compression capabilities 

are best. Sealants should conform to ASTM C 920, Standard Specification for Elastomeric Joint Sealants [Ref. 1], 

Grade NS, Use M, and be sufficiently compressible, resistant to weathering (ultraviolet light) and bond well to 

adjacent materials. Sealant manufacturers should be consulted for the applicability of their sealants for expansion 

joint applications. Compatibility of sealants with adjacent materials such as brick, flashings, metals, etc., also 

must be taken into consideration. Manufacturers recommend three generic types of elastomeric sealants for use 

on brickwork: polyurethanes, silicones and polysulfides. Most sealants suitable for use in brickwork expansion 

joints meet an ASTM C 920 Class 25 or Class 50 rating that requires them to expand and contract by at least 

25 percent or 50 percent of the initial joint width, respectively. Sealants meeting Class 50 are recommended to 

minimize the number of joints. Many sealants require a primer to be applied to the masonry surface to ensure 

adequate bond. 

Use a circular foam backer rod behind sealants to keep the sealant at a constant depth and provide a surface 

to tool the sealant against. The sealant must not adhere to the backer rod. The depth of the sealant should be 

approximately one-half the width of the expansion joint, with a minimum sealant depth of 




 in. (6.4 mm).

Photo 1

Vertical Expansion Joint Construction


Figure 1

 shows typical methods of forming vertical 

expansion joints with either a premolded foam pad, a 

neoprene pad or a backer rod. 

While generally limited to rain screen walls, a two-stage 

joint as shown in 

Figure 2 

can increase resistance to 

water and air infiltration. This type of joint provides a 

vented or pressure-equalized joint. The space between 

the sealants must be vented toward the exterior to allow 

drainage. This is typically achieved by leaving a hole or 

gap in the exterior sealant joint at the top and bottom of 

the joint.


No single recommendation on the positioning and spacing 

of expansion joints can be applicable to all structures. 

Review each structure for the extent of movements 

expected. Accommodate these movements with a 

series of expansion joints. Determine the spacing of 

expansion joints by considering the amount of expected 

wall movement, the size of the expansion joint and the 

compressibility of the expansion joint materials. In addition 

to the amount of anticipated movement, other variables 

that also may affect the size and spacing of expansion 

joints include restraint conditions, elastic deformation 

due to loads, shrinkage and creep of mortar, construction 

tolerances and wall orientation.

The theory and equation for estimating the anticipated extent of unrestrained brick wythe movement are presented 

in Technical Note 18. Estimated movement is based on the theoretical movement of the brickwork attributed to 

each property and expressed as coefficients of moisture expansion (k


), thermal expansion (k


) and freezing 

expansion (k


).  As discussed in Technical Note 18, for most unrestrained brickwork, the total extent of movement 

can be estimated as the length of the brickwork multiplied by 0.0009. A derivative of this equation can be written to 

calculate the theoretical spacing between vertical expansion joints as follows:




































 = spacing between expansion joints, in. (mm)



 = width of expansion joint, typically the mortar joint width, in. (mm)



 = percent extensibility of expansion joint material

The expansion joint is typically sized to resemble a mortar joint, usually 




 in. (10 mm) to 




 in. (13 mm). The width 

of an expansion joint may be limited by the sealant capabilities. Extensibility of sealants in the 25 percent to 50 

percent range is typical for brickwork. Compressibility of filler materials may be up to 75 percent.

Example. Consider a typical brick veneer with a desired expansion joint size of 




 in. (13 mm) and a sealant with 

50 percent extensibility. Eq. 1 gives the following theoretical expansion joint spacing:










     (0.5 in.)(50)  

















278 in. or 23 ft - 2 in. (7.06 m)

Therefore, the maximum theoretical spacing between vertical expansion joints in a straight wall would be 23 ft 

- 2 in. (7.1 m). This spacing does not take into account window openings, corners or properties of other materials |


Brick Industry Association









Accommodating Expansion of Brickwork 



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Figure 2

Two-Stage Vertical Expansion Joint

Figure 1

Premolded Foam Pad

Neoprene Pad

Sealant & Backer Rod

Backer Rod

and Sealant

Vented Cavity |


Brick Industry Association









Accommodating Expansion of Brickwork 



4 of 11

that may require a reduction in expansion joint spacing. 

In most instances it is desirable to be conservative

but it may be economically desirable to exceed the 

theoretical maximum spacing as a calculated risk. For 

example, calculations may result in a theoretical spacing 

of expansion joints every 23 ft – 2 in. (7.06 m) but the 

actual expansion joint spacing is set at 24 ft (7.3 m) 

to match the structural column spacing or a specific 

modular dimension. Vertical expansion joint spacing 

should not exceed 25 ft (7.6 m) in brickwork without 



The actual location of vertical expansion joints in a 

structure is dependent upon the configuration of the 

structure as well as the expected amount of movement. 

In addition to placing an adequate number of expansion 

joints within long walls, consider placing expansion joints 

at corners, offsets, openings, wall intersections, changes 

in wall heights and parapets.

Corners. Walls that intersect will expand toward their 

juncture, typically causing distress on one or both sides 

of a corner, as shown in 

Figure 3a

. Place expansion 

joints near corners to alleviate this stress. The best 

location is at the first head joint on either side of the 

corner; however, this may not be aesthetically pleasing. 

Masons can typically reach about 2 ft (600 mm) around 

the corner from the face where they are working. An 

expansion joint should be placed within approximately 

10 ft (3 m) of the corner in either wall, but not necessarily 

both. The sum of the distance from a corner to the 

adjacent vertical expansion joints should not exceed 

the spacing of expansion joints in a straight wall, 

as shown in 

Figure 3b

. For example, if the spacing 

between vertical expansion joints on a straight wall is 

25 ft (7.6 m), then the spacing of expansion joints around 

a corner could be 10 ft (3.0 m) on one side of the corner 

and 15 ft (4.6 m) on the other side. 

Offsets and Setbacks. Parallel walls will expand toward 

an offset, rotating the shorter masonry leg, or causing 

cracks within the offset, as shown in 

Figure 4a

. Place 

expansion joints at the offset to allow the parallel walls to 

expand, as 

Figure 4b

 illustrates. Expansion joints placed 

at inside corners are less visible.

Openings. When the spacing between expansion joints 

is too large, cracks may develop at window and door 

openings. In structures containing punched windows and 

door openings, more movement occurs in the brickwork 

above and below the openings than in the brickwork 

between the openings. Less movement occurs along 

the line of openings since there is less masonry. This 

differential movement may cause cracks that emanate 

from the corners of the opening, as in 

Figure 5

. This 

pattern of cracking does not exist in structures with 

continuous ribbon windows.

Figure 5

Cracking in Structure with “Punched” 

Windows, Without Proper Expansion Joints

    +      < Typ. Spacing

Between Expansion Jts.

Exp. Jt.

Exp. Jt.







Movement at Corner Without Expansion Joints





    or       <

_ 10 ft.

Either L




Proper Expansion Joint Locations at Corner

Direction of Expansion

Figure 3

Vertical Expansion Joints at Corners



Exp. Jt.

Exp. Jt.

Exp. Jt.

Movement at Offset Without Expansion Joints

Proper Expansion Joint Locations at Offset

Direction of Expansion

Extent of



Figure 4

Vertical Expansion Joints at Offsets |


Brick Industry Association









Accommodating Expansion of Brickwork 



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Window and door openings weaken the wall and act as 

“natural” expansion joints. One alternative is to place 

expansion joints halfway between the windows. This 

requires a sufficiently wide section of masonry between 

the openings, typically 4 ft (1.2 m). It is often desirable 

to locate vertical expansion joints along the edge or 

jamb of the opening. In cases where the masonry above 

an opening is supported by shelf angles attached to 

the structure, a vertical expansion joint can be placed 

alongside the opening, continuing through the horizontal 


If a vertical expansion joint runs alongside an opening 

spanned by a loose lintel as shown in 

Figure 6a

, the loose 

steel lintel must be allowed to expand independently of 

the masonry. A slip plane should be formed by placing 

flashing above and below the angle. Mortar placed in front 

of the lintel is subject to cracking; thus, a backer rod and 

sealant should be used, as shown in 

Figure 6b

. Because 

steel expands more than masonry, a 








 in. (3.2 to 6.4 

mm) space should be left at each end of the lintel. These 

measures form a pocket that allows movement of the 

steel angle within the brickwork. Locating the expansion 

joint adjacent to the window will influence the dead weight 

of the masonry bearing on the lintel. Instead of the usual 

triangular loading, the full weight of the masonry above 

the angle should be assumed to bear on the lintel. See 

Technical Note 31B for more information about steel lintel 

design. If a vertical expansion joint cannot be built in this 

manner, do not place it alongside the opening. 

Junctions. Expansion joints should be located at 

junctions of walls with different environmental exposures 

or support conditions. Separate portions of brickwork 

exposed to different climatic conditions should be 

separated with expansion joints since each area will 

move differently. An exterior wall containing brickwork 

that extends through glazing into a building’s interior 

should have an expansion joint separating the exterior 

brickwork from the interior brickwork. You may need 

to use expansion joints to separate adjacent walls of 

different heights to avoid cracking caused by differential 

movement, particularly when the height difference is very 

large. Examples are shown in 

Figure 7


Parapets. Parapets with masonry exposed on the back 

side are exposed on three sides to extremes of moisture 

and temperature and may experience substantially 

different movement from that of the wall below. Parapets 

also lack the dead load of masonry above to help resist 

movement. Therefore, extend all vertical expansion joints 

through parapets. Since parapets are subject to more 

movement than the wall below, they must be treated 

differently. When vertical expansion joints are spaced 

more than 15 ft (4.6 m) apart, the placement and design of 

expansion joints through parapets need to accommodate 

this additional movement. In this situation, make 

Figure 6

Expansion Joint at Loose Lintel

Figure 7

Expansion Joints at Junctions

Expansion Joint

Steel Lintel Beyond

Backer Rod

and Sealant



Compressible Material

Steel Lintel



Used for

Slip Plane

Backer Rod and


Exp. Joint

Different Environmental Exposure



Different Support Conditions



Expansion Joint

Expansion Joint |


Brick Industry Association









Accommodating Expansion of Brickwork 



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expansion joints in the parapet wider or add expansion joints placed halfway between those running full height. 

These additional expansion joints must continue down to a horizontal expansion joint.


As a third alternative, install 

joint reinforcement at 8 in. (203 mm) on center vertically in the parapet. 

Aesthetic Effects

Although expansion joints are usually noticeable on flat 

walls of masonry buildings, there are ways to reduce 

their visual impact. Architectural features such as quoins, 

recessed panels of brickwork or a change in bond pattern 

reduce the visual impact of vertical expansion joints. In 

some cases, it may be desirable to accentuate the location 

of the expansion joint as a design detail. This is possible by 

recessing the brickwork at the expansion joint, or by using 

special-shaped brick units as shown in 

Photo 2



Colored sealants that match the brick in running bond, or 

the mortar in stack bond, help to hide vertical expansion 

joints. Mason’s sand also can be rubbed into new 

sealant to remove the sheen, making the joint blend in 

more. Expansion joints also are less noticeable when located at inside corners. Hiding expansion joints behind 

downspouts or other building elements can inhibit maintenance access and is not advised. Toothing of expansion 

joints to follow the masonry bond pattern is not recommended. It is more difficult to keep debris out of the joint 

during construction; such debris could interfere with movement. Further, most sealants do not perform well when 

subjected to both shear and tension.

Symmetrical placement of expansion joints on the elevation of buildings is usually most aesthetically pleasing. 

Further, placing the expansion joints in a pattern such that wall areas and openings are symmetrical between 

expansion joints will reduce the likelihood of cracking.

Other Considerations 

Location of vertical expansion joints will be influenced by additional factors. Spandrel sections of brickwork 

supported by a beam or floor may crack because of deflection of the support. Reduced spacing of expansion 

joints will permit deflection to occur without cracking the brickwork. 

Building Code Requirements for Masonry Structures (ACI 530/ASCE 5/TMS 402) [Ref. 4] and most building codes 

allow anchored masonry veneer with an installed weight not exceeding 40 lb/ft


 (1,915 Pa) and a maximum height 

of 12 ft (3.66 m) to be supported on wood construction, provided that a vertical expansion joint is used to isolate 

the veneer supported by wood from the veneer supported by the foundation.



Horizontal expansion joints are typically needed if the 

brick wythe is supported on a shelf angle attached to the 

frame or used as infill within the frame. Placing horizontal 

expansion joints below shelf angles provides space for 

vertical expansion of the brickwork below and deformation 

of the shelf angle and the structure to which it is attached. 

Structures that support the brick wythe on shelf angles, 

usually done for each floor, must have horizontal expansion 

joints under each shelf angle. 

Figure 8

 shows a typical 

detail of a horizontal expansion joint beneath a shelf angle. 

If the shelf angle is not attached to the structure when the 

brick below it are laid, any temporary shims that support the 

angle must be removed after the shelf angle is connected. 

The joint is formed by a clear space or highly compressible 

material placed beneath the angle, and a backer rod and 

Photo 2

Accentuated Expansion Joint

Horizontal Expansion Joint at Shelf Angle

Shelf Angle


Sealant and Backer Rod

Min. 1/4 in. (6 mm) Thick

Compressible Material


Flashing Protection

on Bolt Heads

Figure 8

Expansion Joint at Shelf Angle

sealant at the toe of the angle to seal the joint. It is not necessary to interrupt shelf angles at vertical expansion 

joint locations. However, shelf angles must be discontinuous to provide for their own thermal expansion. A space 

of ¼ in. in 20 ft (6 mm in 6 m) of shelf angle length is typically sufficient. Bolt heads anchoring a shelf angle to the 

structure should be covered to decrease the possibility of flashing puncture.

The size of the horizontal expansion joint should take into account movements of the brickwork and movements 

of the frame. Frame movements include both material and load-induced movements, such as deflections of 

the shelf angle, rotation of the horizontal leg of the shelf angle, and movement of the support from deflection, 

temperature change, shrinkage, creep or other factors. 

When a large horizontal expansion joint is necessary, a lipped brick course may be used to allow movement while 

minimizing the aesthetic impact of the joint. To avoid problems with breakage, the height and depth of the lipped 

portion of the brick should be at least ½ in. (13 mm). Lipped brick should be made by the brick manufacturer for 

quality assurance purposes.

Construction using lipped brick requires careful 

consideration of the frame movements noted 

previously. Allowance for adjacent material tolerances 

including the building frame should also be considered. 

Adequate space should be provided between the 

lipped portion of the brick and the shelf angle to ensure 

no contact. Contact should not occur between the 

lipped brick and the brickwork below the shelf angle 

or between the lip of the brick and the shelf angle, not 

only during construction, but also throughout the life of 

the building.

Lipped brick may be installed as the first course above 

a shelf angle, as shown in 

Figure 9a

. Flashing should 

be placed between the shelf angle and the lipped brick 

course. Proper installation of flashing is made more 

difficult because the flashing must conform to the shape 

of the lip. This shape may be achieved with stiffer 

flashing materials such as sheet metal. If the specified 

flashing materials are made of composite, plastic or 

rubber, a sheet metal drip edge should be used. The 

practice of placing flashing one course above the shelf 

angle is not recommended, as this can increase the 

potential for movement and moisture entry.

Lipped brick also may be inverted and placed on the 

last course of brickwork below a shelf angle, as shown 


Figure 9b

. While installing an inverted lipped brick 

course allows the flashing of the brickwork above to 

maintain a straight profile through the brickwork, it also 

allows the lipped brick course to move independent 

of the shelf angle. Thus, there is an increased 

possibility of the shelf angle coming in contact with 

the lipped brick course, resulting in cracking at the lip. 

It is difficult, if not impossible, to install compressible 

material below the shelf angle. Further, it is likely that 

temporary shims may be left in place between the lipped 

brick and the shelf angle. 

Horizontal expansion joints are also recommended 

when brick is used as an infill material within the frame of the structure. Expansion joints must be provided 

between the top course of brickwork and the member above. Deflections of the frame should be considered when 

sizing the expansion joint to avoid inadvertently loading the brickwork. |


Brick Industry Association









Accommodating Expansion of Brickwork 



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Figure 9

Alternate Expansion Joint Detail

Inverted Lipped Brick


Lipped Brick


Shelf Angle


Sealant and Backer Rod

Min. 1/4” (6 mm) Thick

Compressible Material


Lipped Brick

Flashing Protection

on Bolt Heads

Shelf Angle


Sealant and Backer Rod

Min. 1/4 in. (6 mm) Thick

Compressible Material


Lipped Brick

Flashing Protection

on Bolt Heads |


Brick Industry Association









Accommodating Expansion of Brickwork 



8 of 11


Some buildings with brick veneer construction do not support the brickwork on shelf angles. These typically include 

low-rise buildings constructed with wood and steel stud framing and buildings with shear walls. Building Code 

Requirements for Masonry Structures limits brick veneer with wood or steel stud backing to a height of 30 ft (9 m) 

to the top plate and 38 ft (12 m) to the top of a gable. Brick veneer with a rigid backing of concrete or concrete 

masonry has no such limitation in the code. Brick veneer with this rigid backing may be supported by the foundation 

without intermediate shelf angles to a recommended maximum height of about 50 ft (15 m), provided the building is 

Anchorage to Steel Beam (section)


Anchorage to Steel Column (plan)


Anchorage to Concrete Beam (section)


Anchorage to Concrete Column

or Wall (section)




Dovetail Anchor



Dovetail Slot



Dovetail Slot




Anchor Rod

Wire Anchor



Joint Reinf.

with Eye &





Joint Reinforcement

with Eye & Pintle



Compressible Filler

Flashing Membrane

Adjustable Ties

Figure 10

Flexible Anchorage to Beams and Columns |


Brick Industry Association









Accommodating Expansion of Brickwork 

Page 9 of 11

detailed appropriately for the differential movement and the moisture drainage system is designed and constructed 

properly. In these buildings, differential movement is accommodated by the anchor or tie system, window details, 

detailing at top of the wall and where other building components pass through the brickwork. These details must 

provide independent vertical movement between the brickwork and the backing. Building components that extend 

into or through the brick veneer (e.g., windows, doors, vents, etc.) also must be detailed to allow independent 

vertical movement of the brick veneer and the component. The structural frame or backing provides the brick 

veneer with lateral support and carries all other vertical loads. The veneer is anchored by flexible connectors or 

adjustable anchors that permit differential movement. Allowance for differential movement between the exterior 

brickwork and the adjacent components should be provided at all openings and at the tops of walls. Vertical 

expansion joints also must be incorporated, as discussed in previous sections of this Technical Note.

Connectors, anchors or ties that transfer load from the brick wythe to a structural frame or backing that 

provides lateral support should resist movement perpendicular to the plane of the wall (tension and 

compression) but allow movement parallel to the wall without becoming disengaged. This flexible anchorage 

permits differential movements between the structure and the brickwork. 

Figure 10

 shows typical methods 

for anchoring masonry walls to columns and beams. Technical Note 44B provides detailed information about 

masonry ties and anchors.

The size and spacing of anchors and ties are based on tensile and compressive loads induced by lateral loads 

on the walls or on prescriptive anchor and tie spacing requirements in building codes. Technical Note 44B lists 

recommended tie spacing based on application.

There must be sufficient clearance among the masonry elements and the beams and columns of the structural 

frame to permit the expected differential movement. The masonry walls may be more rigid than the structural 

frame. This clearance provides isolation between the brickwork and frame, allowing independent movement.


Movement joints must be provided in multi-wythe brick and 

concrete masonry walls. Expansion joints are placed in the 

brick wythe, and control joints are placed in the concrete 

masonry, although they do not necessarily have to be 

aligned through the wall.

Bond Breaks

Concrete and concrete masonry have moisture and 

thermal movements that are considerably different from 

those of brick masonry. Floor slabs and foundations also 

experience different states of stress due to their loading 

and support conditions. Therefore, it may be necessary 

to separate brickwork from these elements using a bond 

break such as building paper or flashing. Such bond 

breaks should be provided between foundations and 

walls; between slabs and walls; and between concrete 

and clay masonry, to allow independent movement while 

still providing gravity support. Typical methods of breaking 

bond between walls and slabs, and between walls and 

foundations are shown in 

Figure 11


When bands of clay brick are used in concrete masonry 

walls, or when bands of concrete masonry or cast stone are 

used in clay brick walls, differences in material properties 

may cause mortar joints or masonry units to crack. Such 

problems can be easily avoided by using bands of brickwork featuring brick of a different color, size or texture or 

a different bond pattern. If, however, a different material is used for the band, it may be prudent to install a bond 

break between the two materials, provide additional movement joints in the wall, or place joint reinforcement in the 

bed joints of the concrete masonry to reduce the potential for cracking.

Bond Break




Flashing as

Bond Break

Concrete Roof


Figure 11

Bond Breaks in Loadbearing Cavity Wall

Breaking the bond in this way does not affect the 

compressive strength of the wall and should not affect 

the stability of the veneer wythe when anchored properly. 

The weight of the masonry, additional anchorage and 

the frictional properties at the interface provide stability. 

Sealant at the face of the joints between the different 

materials will reduce possible water entry. If the band is 

concrete masonry or cast stone, additional control joints are 

recommended in the band. If the band is a single course, 

there is a likelihood of vertical cracks at all head joints. 

These can be closed with a sealant. Bands of two or more 

courses should include horizontal joint reinforcement in 

the intervening bed joints, as shown in 

Figure 12



The potential for cracking in loadbearing masonry 

members is less than in nonloadbearing masonry 

members because compressive stresses from dead and |


Brick Industry Association









Accommodating Expansion of Brickwork 


Page 10 of 11

Sealant in Raked Joint

(Typical) (Optional)

Joint Reinforcement

and Adjustable Anchor

in CMU Veneer Band

Bond Breaker


Adjustable Anchor


Brick Veneer

CMU Veneer


Figure 14

Bond Breaks

Bond Break Material


Anchor Bolt

Steel Plate

Bond Break at Foundation


Anchor Bolt

Bond Break at Roof


Bond Beam

Lath or

Hardware Cloth

Figure 12

Multi-Course Concrete Masonry Band 

in Brick Veneer

Figure 13

Bond Beams

Bond Beam

Hollow Brick Construction


Cavity Wall Construction


Lath or

Hardware Cloth

Bond Beam

live loads help offset the effects of any movement. Adding reinforcement at critical sections such as parapets, 

points of load application and around openings to accommodate or distribute high stresses will also help control 

the effects of movement. Reinforcement may be placed in bed joints or in bond beams, as shown in 

Figure 13

Historic loadbearing structures were not constructed with expansion joints. However, these walls were made of 

multi-wythe brick construction, unlike typical structures built today. 

When it is necessary to anchor a masonry wall to a foundation or to a roof, it is still possible to detail the walls in a 

manner that allows some differential movement, as shown in 

Figure 14a 


 Figure 14b

. Such anchorage is often 

required for loadbearing walls subjected to high winds or seismic forces.


This Technical Note defines the types of movement joints used in building construction. Details of expansion joints 

used in brickwork are shown. The recommended size, spacing and location of expansion joints are given. By using 

the suggestions in this Technical Note, the potential for cracks in brickwork can be reduced.

Expansion joints are used in brick masonry to accommodate the movement experienced by materials as they 

react to environmental conditions, adjacent materials and loads. In general, vertical expansion joints should be 

used to break the brickwork into rectangular elements that have the same support conditions, climatic exposure 

and through-wall construction. The maximum recommended spacing of vertical expansion joints is 25 ft (7.6 m).


Horizontal expansion joints must be placed below shelf angles supporting brick masonry.

The information and suggestions contained in this Technical Note are based on the available data 

and the combined experience of engineering staff and members of the Brick Industry Association. 

The information contained herein must be used in conjunction with good technical judgment 

and a basic understanding of the properties of brick masonry. Final decisions on the use of 

the information contained in this Technical Note are not within the purview of the Brick Industry 

Association and must rest with the project architect, engineer and owner.


1.  ASTM C 920, Standard Guide for Use of Elastomeric Joint Sealants, Annual Book of Standards, Vol. 

04.07, ASTM International, West Conshohocken, PA, 2006.

2. Beall, 


Masonry Design and Detailing for Architects, Engineers and Contractors, Fifth Edition, McGraw 

Hill, Inc., New York, NY, 2003.

3.  Beall, C., “Sealant Joint Design,” Water on Exterior Building Walls: Problems and Solutions, ASTM STP 

1107, T.A. Schwartz, Ed., ASTM, West Conshohocken, PA, 1991.

4.  Building Code Requirements for Masonry Structures (ACI 530-05/ASCE 5-05/TMS 402-05), The Masonry 

Society, Boulder, CO, 2005. 

5.  “Building Movements and Joints,” Portland Cement Association, Skokie, IL, 1982. |


Brick Industry Association



TN 18A




Accommodating Expansion of Brickwork




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