Design Handbook: Section 4
Architectural Details: Roofing Systems
Special Considerations
One of the most important issues in the use of copper is the relative movement of components. Movement can occur as a result of internal stresses due to temperature changes, or from external sources such as wind, ice, or movement in the substrate. Since copper is most often used as a water barrier, installations must account for the anticipated movement as well as prevent the infiltration of water.
This section presents key information on practical limits and Special Conditions. For additional information on thermal stresses see Fundamentals - Structural Considerations.
Providing an effective path for water to flow in a controlled direction is one of the most important principles in design and construction. Table 4.2.A shows the recommended minimum slopes for various copper roofing systems using the details shown throughout this Handbook. Lower slopes are possible under certain conditions, using modified details. Table 4.2.B shows the minimum recommended slopes using these special details. The modified details are discussed below. Only flat seam roofing is constructed to be completely watertight, and therefore can sustain standing water. Table 4.2.C outlines the recommendations regarding flat seam construction.
Mansard roofs are usually steep, but they often have changes in their slope. They are based on either standing or batten seam roofing. The minimum recommendations, are therefore, the same as the "base" standing or batten seam roof. The following discussion is for Special Conditions. See Table 4.2.B.
A. Standing Seams Before the two pans are locked, a good quality rubber or synthetic based sealant should be applied to the top of the flange of the lower pan. Transverse seams should be based on the "low pitch" version of Detail C.
B. Batten Seams A good quality rubber or synthetic based sealant should be applied to the top flange of each pan prior to installation of the batten cap.
C. Batten Cap Where batten caps join, a 3" lapped seam is required.
The optional cleat shown can be used to hold the roofing pans during installation. This is particularly helpful on a steep roof.
| Conditions | Standing Seam | Batten Seam | Chevron | Horiz. Seam | Mansard |
|---|---|---|---|---|---|
| Where ice, snow, and heavy rain do not occur | 3 | 3 | 3 | 3 | See Batten or Standing Seam |
| Ice and snow conditions | 4 | 4 | 4 | 4 | See Batten or Standing Seam |
| Heavy rain conditions | 4 | 4 | 4 | 4 | See Batten or Standing Seam |
| Slopes are in inches per foot. | |||||
| Conditions | Standing Seam | Batten Seam | Chevron | Horiz. Seam | Mansard |
|---|---|---|---|---|---|
| Where ice, snow, and heavy rain do not occur | 1 | 2 | 2 | N/R | See Batten or Standing Seam |
| Ice and snow conditions | 3 | 3 | 3 | N/R | See Batten or Standing Seam |
| Heavy rain conditions | 3 | 3 | 3 | N/R | See Batten or Standing Seam |
| Slopes are in inches per foot. N/R = Not Recommended | |||||
| Slope | Remarks |
|---|---|
| 0-3 | Seams fully soldered |
| 3-6 | Seams may be fully sealed |
| >6 | Neither sealant nor solder is required in seams |
| Slopes are in inches per foot. | |
Architecture Design Handbook
AutoCAD Detail Files
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Use this link to download the complete set of CAD files for the designs shown in Section 4 - Architectural Details. The AutoCAD files for individual detail topics can be downloaded by using the "CAD File" button in the page for the topic.
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Notice: This Handbook has been prepared for the use of architects and other design and construction professionals. It has been compiled from information supplied by testing, research, manufacturing, standards, and consulting organizations that Copper Development Association Inc. believes to be competent sources for such data. However, recognizing that each system must be designed to meet the particular circumstances, CDA assumes no responsibility or liability of any kind in connection with this Handbook or its use by any person or organization, and makes no representations or warranties of any kind hereby.
