Retrofit Roof Subframe Rib Flange Design
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional subframe systems for retrofitting metal roofs often fail to provide the necessary strength and compatibility with new construction practices, especially in transitioning from older roof configurations, and may require inefficient production and time-consuming installation processes.
Innovation Solution
A subframe configuration that connects to the upper surface and valley/purlin of the existing roof using a mechanical interference connection or connector, featuring a rib flange that extends from the bottom of the lip, with a base secured to the purlin and a wall that can accommodate insulation, providing increased height and resistance to lateral and torque forces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If conventional subframe systems are used for retrofitting metal roofs, then installation can be performed over existing roof decking, but the systems fail to provide necessary strength and compatibility with new construction practices
Solution Approach 1:
The subframe is divided into multiple components including a base portion, upright portions, and flanges that can be separately manufactured and assembled. This segmentation allows each component to be optimized for specific functions - the base for attachment to existing structure, the uprights for providing height and insulation space, and the flanges for connecting to new roof decking, thereby achieving both strength and compatibility with modern construction practices
Solution Approach 2:
The subframe system combines different metal components with varying properties - the base portion uses materials optimized for attachment to existing roof decking, while the upright portions and flanges use materials optimized for structural strength and connection to new decking. This composite approach allows the system to meet both legacy compatibility and modern strength requirements
2Productivity
If conventional subframe systems are used, then they can be manufactured from standard materials, but they require inefficient production and time-consuming installation processes
Solution Approach 1:
The subframe components are pre-assembled with the upright portions, flanges, and base portions connected before delivery to the job site. This preliminary assembly reduces on-site installation time significantly, as workers simply need to attach the pre-assembled units to the existing roof structure and new decking, rather than assembling multiple separate components during installation
Solution Approach 2:
The subframe design incorporates multiple functions into single components - the base portion serves both as the attachment point to existing roof decking and as the mounting surface for upright portions; the flanges provide both structural connection to new decking and attachment points for roofing materials. This multi-functionality reduces the total number of components and simplifies both manufacturing and installation
Data Source
AI summary
A subframe configuration for a retrofit roof includes a subframe connected to the upper surface of a rib on an existing roof. The subframe is also connected to the valley/purlin of the existing roof. The connection can be a mechanical interference connection or one that is formed by a mechanical connector. The subframe of the disclosure includes a rib flange that extends from the bottom of the lip. The rib flange is disposed substantially parallel to the base of the subframe. When installed, a connector extends through the rib flange into a rib of the existing roof. Rib flange can be continuous or provided only at each or just some of the ribs.