Masonry Magazine August 1980 Page. 15
BIA Technical Notes on Brick Construction
Brick Institute of America 1750 Old Meadow Road, McLean, Virginia 22102
BRICK VENEER EXISTING CONSTRUCTION
INTRODUCTION
The application of brick veneer to existing construction is popular because it enhances the appearance and improves the performance of existing walls. Its most common application is in refinishing the exterior of one and two-family dwellings, and also in refacing the fronts of commercial buildings.
Brick veneer over existing construction consists of a nominal 3-in. (75 mm) or 4-in. (100 mm) thick brick wythe attached to an existing wall with metal ties in such a way that a 1-in. (25 mm) air space is maintained between the new brick veneer and the existing wall. New brick veneer can be applied to wood frame, metal, concrete or masonry structures.
This Technical Notes considers the application of brick veneer to various types of existing construction. The illustrations, however, show only brick veneer applied to existing wood frame structures. This is the most common application. Details for brick veneer applied to other types of construction are similar, the method of attachment varying with the type of existing construction.
PROPERTIES
In addition to improving the appearance of the existing structure, the application of brick veneer may also enhance many of the performance properties of the wall and structure to which it is applied.
Thermal Properties
The thermal properties of a wall are improved by the addition of brick veneer in two ways the addition of mass and the reduction of infiltration. The application of brick veneer also provides an opportunity to add insulation if desirable.
Additional information on the thermal properties of brick veneer and brick masonry in general may be found in Technical Notes 28 Revised, and Technical Notes 4 Series.
Moisture Resistance
The moisture resistance of a wall can also be improved by the application of properly detailed and installed brick veneer. See Technical Notes 28 Revised, 7 Series and 21C for further information.
Fire Resistance
Constructing brick veneer over existing walls of combustible materials will decrease the possibility of externally initiated fires. Typical brick veneer wall assemblies have fire resistance ratings up to 2 hr.
Acoustical Properties
The addition of brick veneer to an existing wall will improve the sound transmission loss of the wall. This is due to the addition of mass and the discontinuity of the system. Further information is given in Technical Notes 28 Revised and Technical Notes 5A.
DESIGN AND DETAILING
Proper design and detailing of brick veneer applied to existing construction is very important to ensure that the wall assembly acts as it is intended. Areas of concern in design and detailing are structural performance, supporting the veneer, attaching the veneer to the existing structure, flashing and weepholes, movement provisions, framing around openings, and the top of the veneer.
Structural Design
Brick veneer is a non-loadbearing component of the wall assembly. In addition to its own weight, the only load that the brick veneer should carry is a proportionate share of any lateral loads. The wide differences between the stiffness characteristics of the brick veneer and those of the existing wall that usually occur result in the brick veneer carrying a disproportionate share of the lateral loads not considered in the design.
TABLE 1
Empirical Height Limitations for Brick Veneer
| Nominal Thickness of the Brick Veneer, in (mm) | Stories | Height at Plate, ft (m) | Height at Gable, ft (m) |
|---|---|---|---|
| 3 (75) | 2 | 20 (6.10) | 28 (8.53) |
| 4 (100) | 3 | 30 (9.14) | 38 (11.58) |