Masonry Magazine October 1980 Page. 18
ROOFING
FRICTION-FIT METAL COPING
SEALANT
HORIZONTAL AND VERTICAL
REINFORCEMENT
1"(25 mm) MINIMUM AIR SPACE
COUNTER FLASHING
METAL TIES
SEALANT
DOVETAIL ANCHOR
FLEXIBLE
ANCHOR
BUILDING
PAPER (OPTIONAL)
WIRE TIE
BRICK VENEER
MAXIMUM 125 mm)
AIRSPACE
RIGID SHEATHING
STEEL STUDS
SELF-TAPPING
CORROSION-RESISTANT
METAL SCREW
INSULATION
RIGID
WALLBOARD
Non-Parapet Wall
FIG. 9
FLEXIBLE
WIRE TIE WITH
DOVETAIL ANCHOR
AND SLOT
METAL STUD
FRAMING
Reinforced Parapet Wall
FIG. 10
Metal Studs. To provide lateral support, and to permit the use of the full allowable stress in the design of the metal studs, there must be sheathing securely attached to both sides of the studs. This sheathing must be rigid, properly detailed, and properly attached for it to be effective.
Horizontal bracing of the studs at mid-height is recommended for added strength, stiffness and fire-stopping. Studs at all jambs, headers and sills of windows, doors and other openings should be designed with loads based on the tributary area of the opening with adequate transfer of loads to the structure within the deflection criteria.
Ties. There should be one tie for each 235 sq ft (0.25 m²) of wall area, spaced a maximum 24 in. (600 mm) o.c. vertically and horizontally as shown in Fig. 7. These should be minimum 9 gage corrosion-resistant wire ties of the type shown in Fig. 8. Corrugated metal veneer ties should not be used. All ties must be embedded at least 2 in. (50 mm) into the bed joints of the brick veneer. They must be securely attached to the metal studs through the sheathing, and not to the sheathing alone.
Mortar. The mortar has an important effect on the strength of a brick veneer wall. Transverse strength tests of full-scale walls have shown that the bond between mortar and brick units is the most important single factor affecting wall strength when the load is applied such that failure occurs through a horizontal joint.
These tests indicate that portland cement-lime mortars, under ASTM C 270 or BIA M1-72, Type S, provide maximum bond between masonry units and mortar. Type S mortar is recommended for use in brick veneer walls at locations where wind loads are expected to exceed 25 psf (1.2 kPa). For other locations, Type N mortar may be used. The designer, in any case, should select the lowest strength mortar that is compatible with the structural requirements. Only portland cement-lime mortars for brick masonry as discussed in Technical Notes 8 Series should be used with veneer panel and curtain walls above three stories.
Brick Veneer. If it is not possible to increase the stiffness of the metal stud backup system sufficiently to take its share of the lateral load, several methods are available to adequately size the walls.
Thickness-Increase the thickness of the brick veneer itself sufficiently so that it is capable of resisting all of the lateral loads.
Reinforced Brick Masonry-The use of hollow brick units with reinforced and grouted cells is a possibility. This type of wall will be most beneficial in severe earthquake zones.
Backup System-The designer may wish to consider changing the backup system from metal studs to masonry. It may be more advantageous to use a cavity wall or insulated cavity wall design instead of a brick veneer design, see Technical Notes 21 Series.
Parapet Walls. Parapet walls should be avoided unless absolutely necessary, see Fig. 9. If they must be used, they should be properly designed, detailed, and constructed, see Fig. 10.
WATER PENETRATION
General
Lack of "Standard Accepted" Details. Another area of concern involves the problems of water penetration. The majority of these problems occur because there are no "standard accepted" details available for this