金属屋顶上的金属和单层改造屋顶系统的比较

Although metal roofs have a decades-long service life, when they do eventually reach the end of their life building owners must decide to either repair, replace, or retrofit. Retrofitting has a number of advantages, making it a popular solution. However, when building owner's chose to retrofit their existing metal roof, they have a couple of options.

The金属建筑制造商协会（MBMA）published a whitepaper,Comparison of Retrofit System Over Existing Metal Roofs, by Brian Gardiner that dives deep into the options available to building owners. “The goal of this paper is to compare two commonly used methods of retrofitting existing metal roofs and illustrate important design considerations that frequently apply to candidate buildings.”

The two most common retrofit options are metal over metal and single-ply over metal. Both options allow for the original roof to remain in place, meaning that the building does not experience disruption to operations, and reuses the existing insulation. Because the original roof remains, retrofitting also cuts down on landfill waste and can reduce costs (no labor or disposal costs associated with roof removal). However, not all projects can safely accommodate a single-ply retrofit over an existing metal roof.

确定哪种翻新选项是最好的包括建筑代码要求和设计注意事项时必须考虑的一些考虑因素。例如，单层改造可能导致池塘水可以灾难性后果.

Ultimately the whitepaper recommends that building owners, “Engage a licensed professional engineer practicing structural engineering with knowledge of metal buildings to evaluate the unbalanced loads and potential water accumulation on a single-ply retrofit roof with respect to structural capacity and drainage provisions.” Also, “the retrofit roof designer should verify the fire classification both above and below the retrofit roof system for building code compliance and building insurer acceptance for the retrofit roof system.”

您可以阅读现有金属屋顶上的翻新系统的完整比较白皮书这里to learn more about each of these considerations, or you canvisit the MBMA website有关更多信息。