Tn 18A web-nov06. indd

Photo 2

Accentuated Expansion Joint

Horizontal Expansion Joint at Shelf Angle

Shelf Angle

Weep

Sealant and Backer Rod

Min. 1/4 in. (6 mm) Thick

Compressible Material

Flashing

Flashing Protection

on Bolt Heads

Figure 8

Expansion Joint at Shelf Angle

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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 

in 

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.

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