13. Domes, Spires and Vaults


Domes, spires, and vaults are designed in a wide variety of shapes. They are not limited to simple geometry, such as circular domes and conical spires. Complex curved surfaces and multi-faceted designs can easily be formed in copper. The concepts shown in this section, can be adapted to any of these situations.

The details shown in this section are based on the principles of standing seam, batten seam, flat seam, and diagonal flat seam roofing. When detailing a dome, spire, or vault, the substrate, underlayment, fastening, and seam design recommendations given in the Roofing Systems section generally apply. The designer should also consider the effects of variations in slope. For example, a transverse seam detail near the base of a dome (which is at a high pitch) is not recommended for the top of the dome (where the pitch is low).

Special attention should be given to the areas where domes and spires intersect adjoining roof surfaces. The resulting valleys require details to prevent "back-up" of water, especially in cold climates prone to ice and snow.

The proper ventilation of the underside of domes, spires, and barrel vaults is particularly important. The location of vents at the bases of cupolas and at the caps terminating domes and spires must be addressed.

The location and design of vents is dependent on project location, climate, and use. The designer is urged to address these issues on a project-by-project basis.

For both simple and complex shapes, it is usually easier to lay out the roofing pans and panels directly on the dome than it is to develop them from drawings. The pans or panels can be field or shop fabricated, but the dimensions should be generated and dictated by the size and shape of the dome.

Equipment Available:

Special equipment is available to form copper into curved shapes. Such equipment is particularly useful in fabricating spherical copper caps and for "stretching" portions of copper flashing to accommodate curved surfaces.