Masonry Magazine February 1982 Page. 29
BIA Technical Notes
Von Brick Construction
Brick Institute of America 1750 Old Meadow Road, McLean, Virginia 22102
36
Revised
Jul/Aug
1981
July/August 1981
40
BRICK
DESIGN ELEMENTS
BRICK MASONRY DETAILS
SILLS AND SOFFITS
Abstract: Detailing of brick masonry is both an art and a science. Recommendations are provided for the development of successful details using brick masonry and other materials. Detailing of sills and soffits is specifically addressed. Performance, esthetic value and economics are the principal considerations in the development of successful details.
Key Words: brick, connections, construction, design, detailing, economics, esthetic value. function, performance, prefabrication, sills, soffits, structural stability.
INTRODUCTION
Successful detailing of brick masonry is both an art and a science. Proper details should result in a structure which is pleasing to the eye, but more importantly, performs well over its lifetime. Good detailing is not accidental, it requires proper planning. This planning may involve close cooperation between the architectural, engineering and construction disciplines in the early stages of the design process.
There are three items which should be considered in the development of a successful detail. These are: 1. Performance considerations; 2. Esthetic value considerations; and 3. Economic considerations. The last two of these items may be traded off against each other. But, the first is mandatory and if it is not the primary concern, the detail may, and probably will, be doomed to failure. This failure can manifest itself in several ways: cracking, structural failure, moisture penetration to the interior, or efflorescence, to mention a few.
It is possible to have a successful detail while compromising either the esthetic value or the economic considerations. But, it it impossible to have a successful detail if the performance considerations are compromised. A successful detail can be developed with excellent esthetic value while completely ignoring the economic considerations or vice versa, but to ignore the performance considerations is to invite trouble.
APPROACH TO DETAILING
# General
Proper planning in the development of brick details is essential to the successful execution of that detail in the field. The designer must be familiar not only with the properties of the various materials involved, but also how they go together in the construction process and how they will perform, both individually and together in service. The most esthetically pleasing detail is of no benefit if it can't be built, or does not perform its intended function.
The designer should always keep in mind that different materials react to temperature and moisture changes in different ways. While in some cases these differences may be minor, in others they may be significant. If they are not properly addressed, the result can be facade failures, such as leaking, bowing, cracking, etc. For a discussion of differential movement, see Technical Notes 18 Series.
# Performance Considerations
Performance is all-important if the detail is to be successful. There are three items which must be considered in the development of a detail which will provide satisfactory performance. They are: 1. Functional considerations; 2. Structural stability; and 3. Construction considerations. In the development of the detail, it is imperative that all of these items be given proper consideration.
# Functional Considerations
One of the first steps in the development of a successful detail is to determine the function of the element. The designer must determine the purpose of the element, and how the element will affect the overall performance of the building. Typical questions which should be addressed are: 1. Is the element to serve as a weather-tight enclosure? 2. Will stresses, axial, flexural or shear, be developed in the member? 3. Should it channel and direct the flow of moisture? 4. Is it to seal the top of a vertical element? 5. Is its purpose merely for esthetic value? Only after the designer has determined the required functions of the element can he begin to consider the other factors which will dictate the final design.
# Structural Stability
The designer must develop a detail which ensures that all applied loads can be adequately resisted by the element or that they are transferred to other elements of the structure which can