Modular Window Sub-Sill Unit with Deflection Wall
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Solution Overview
Problem
Current window sill systems face issues with water infiltration, structural integrity, and fastener reliability due to design flaws, leading to leakage and failure under various environmental conditions such as wind, earthquakes, and temperature changes, and they are not adaptable to diverse window and door types.
Innovation Solution
A modular bottom sub-sill unit with a water trough and weep holes for improved water drainage, combined with a base plate for secure fastening and an inner deflection wall to prevent water from reaching fasteners, along with end dams for sealing, creating a Dry Zone and ensuring effective water management and structural attachment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If fasteners are used to secure window sill systems to the building structure, then structural attachment is achieved, but water infiltration occurs through the fastener holes
Solution Approach 1:
The window sill system is divided into multiple components: a base plate for structural attachment, a separate flashing layer for water management, and an integrated drainage system. This segmentation allows the fastening function and water protection function to be separated, enabling fasteners to provide structural attachment without compromising water infiltration resistance through the flashing layer's continuous membrane and drainage pathways
Solution Approach 2:
A flashing layer acts as an intermediary between the base plate and the exterior environment. This flashing layer includes a continuous waterproof membrane that bridges across fastener holes, and an integrated drainage system with weep holes and drainage planes that intercept and channel water away from the fastener penetration points, preventing water infiltration while maintaining structural attachment
2Ease of manufacture
If conventional window sill systems are used, then basic water drainage is provided, but leakage occurs under environmental stresses such as wind, earthquakes, and temperature changes
Solution Approach 1:
The window sill system incorporates movement joints and flexible sealing components that accommodate thermal expansion and contraction, as well as building movement from wind and earthquakes. The drainage system includes flexible connections and adjustable components that maintain their function under dynamic loading conditions, preventing leakage while maintaining basic water drainage capability
Solution Approach 2:
The system includes pre-installed drainage pathways, weep holes, and waterproof membranes that are positioned and configured before final installation. These features create a redundant drainage system that can handle unexpected water infiltration from various environmental stresses, providing a buffer against leakage while maintaining ease of manufacture through standardized components
3Strength
If fasteners penetrate through the window sill and sill flashing to achieve anchorage, then structural soundness is improved, but the fasteners create potential leakage paths
Solution Approach 1:
The fastening system is segmented into a base plate that provides structural anchorage and a separate flashing layer that provides water protection. The base plate contains the fasteners and their associated drainage management features, isolating the complex fastener configuration from the water barrier function. This allows robust anchorage through multiple fasteners while the flashing layer's continuous membrane and integrated drainage system prevent leakage paths at the penetration points
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution provides superior water drainage, enhanced structural integrity, and extended lifespan by preventing water infiltration and ensuring secure fastening, accommodating various window and door types, and meeting stringent hurricane codes, with customizable designs for long-lasting performance.
Implementation Method 1
water trough or channel extending across its length at a front edge facing outwardly of a window unit to which the sub-sill unit is mounted. The water trough or channel has a top plate provided with a plurality of weep holes for capturing rainwater dripping down the window into the water trough or channel
Implementation Method 2
An inner deflection wall deflects water from the weep holes into the water trough or channel to prevent water from reaching the fastener screws below the inner deflection wall
Data Source
AI summary
An improved window sill system has a modular bottom sub-sill unit to be attached to a bottom part of a window unit and mounted to a bottom frame part of a window frame in an opening in an exterior wall of a building in order to provide improved water drainage for the window sill system. The bottom sub-sill unit has a water trough or channel extending across its length at a front edge facing outwardly of a window unit to which the sub-sill unit is mounted. The water trough or channel has a top plate provided with a plurality of weep holes for capturing rainwater dripping down the window into the water trough or channel. A base plate is provided for mounting the bottom sub-sill unit with fastener screws to the bottom frame part of the window frame. An inner deflection wall deflects water from the weep holes into the water trough or channel to prevent water from reaching the fastener screws in a dry zone below the inner deflection wall.