Under Flashing Corner Element for Roof Felt Drainage Support
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Solution Overview
Problem
Existing flashing systems for roof elements installed in a lowered position in sloping roofs with roofing felt fail to provide adequate support and sealing, especially at the lower corners, leading to issues with water drainage and roofing felt installation.
Innovation Solution
An under flashing corner element with a sloping portion and stabilizing features, along with a bridging element, is used to support roofing felt and ensure proper water drainage by positioning it between the roof element and the adjacent roof edge, providing a stable and watertight installation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Shape
If a roof element is installed in a lowered position (Encastrée manner) in a sloping roof with roofing felt, then the aesthetic appearance and integration with the roof surface is improved, but adequate support and sealing of the roofing felt at the lower corners becomes difficult to achieve
Solution Approach 1:
The flashing system is divided into multiple components: upper flashing members, side flashing members, bottom flashing member, and corner elements. Each segment performs a specific function, with corner elements specifically designed to address the sealing and support issue at the lower corners where roofing felt installation is difficult in lowered position installations.
Solution Approach 2:
Corner elements act as intermediary components between the roofing felt and the roof structure at the lower corners. These elements provide the necessary support and sealing function that cannot be achieved by standard flashing members alone, mediating the gap between the lowered roof element position and the need for reliable roofing felt installation.
2Ease of operation
If standard flashing members are used for a lowered roof element installation, then the installation procedure is simplified, but water drainage and sealing at the lower corners becomes inadequate
Solution Approach 1:
The corner elements have specific local geometries designed for their particular function at the lower corners. The L-shaped cross-section with a first leg against the roof element side and a second leg extending parallel to the roof covering plane provides localized support and sealing exactly where needed, rather than requiring a complete redesign of all flashing members.
Solution Approach 2:
The corner elements utilize three-dimensional positioning with legs extending in different directions (vertically against the roof element and horizontally along the roof surface) to create effective water drainage paths and sealing surfaces that address the multi-directional water flow challenges in sloping roofs.
3Area of stationary object
If the lower face of the roof element is positioned close to the adjacent edge of the opening, then the installation space is optimized, but space for the lifting portion of the bottom flashing member is insufficient
Solution Approach 1:
The corner elements are designed with flexible or adjustable components that can adapt to varying installation spaces. The stabilizing portions can be configured to provide the necessary support for roofing felt while accommodating different distances between the lower face of the roof element and the adjacent edge of the opening.
Data Source
Figure 1~3
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Figure 8~9
AI summary
An under flashing corner element (19) for supporting roofing felt at a lower corner of e.g. a roof window in a sloping roof covered by roofing felt, comprises a plane, generally L-shaped, first portion (21) extending in a first plane and comprising a side leg (23); a bottom leg (25) with an inner side edge (27); and a plane, sloping portion (31) extending from the inner side edge (27) and sloping downwards from the first plane at an acute angle to a second side edge (33). The sloping portion (31) further comprises a proximal side edge (35) extending from the first side edge (27) to the second side edge (33) and a distal side edge (37) extending from the first side edge (27) to the second side edge (33). One or more stabilising portions (39, 43) are extending from the sloping portion (31) towards the first plane.