Sill Drainage Member for Timber Window Moisture Management
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Solution Overview
Problem
Current methods for preventing moisture entry in window glazing assemblies, particularly in timber joinery, are inadequate, leading to issues like rotting timber sills and lack of weather tightness, which hinders the installation of double glazing units and reduces their appeal due to installation difficulties and lack of guarantees.
Innovation Solution
A sill drainage member with a polygonal shape and recessed drainage system is introduced, which includes a sloping upper surface and downwardly protruding features to collect and direct moisture away from the window sill, ensuring effective drainage and installation under the sash bottom rail, along with a method for installing insulated glass units that involves rebating and affixing the drainage member to the sash bottom rail.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If flexible sealing strips or caulking are used to prevent moisture entry, then moisture prevention is attempted, but the seals break down in sunlight and installation is dependent on skilled workers causing improper installation and leaking
Solution Approach 1:
The window assembly is segmented into distinct drainage zones: the recessed area collects moisture, the sill drainage member channels it, and the flashing directs it away. This segmentation replaces the single-point sealing approach with a distributed drainage system, eliminating reliance on vulnerable flexible seals while providing reliable moisture management through multiple functional components working together
Solution Approach 2:
The sill drainage member acts as an intermediary component between the window sill and the flashing. It receives moisture that penetrates the window assembly, channels it through its recessed structure, and directs it to the flashing for outward discharge. This intermediary device protects the building interior by providing a controlled pathway for moisture evacuation, eliminating the need for imperfect flexible seals
2Adaptability or versatility
If putty and glass are removed to install double glazing units, then double glazing can be installed, but the removal process is difficult and messy causing glass breakage and additional costs
Solution Approach 1:
The sill drainage member is pre-installed into the window sill before the double glazing unit is fitted. The recessed structure is prepared in advance to receive and channel moisture. This preliminary action eliminates the need for difficult post-installation modifications and provides a ready-made drainage pathway that simplifies the overall installation process while enabling double glazing capability
Solution Approach 2:
The sill drainage member serves multiple functions: it provides structural support for the double glazing unit, creates a moisture collection recess, channels condensed moisture away from the interior, and interfaces with the flashing system. This multi-functional component replaces multiple separate elements, simplifying installation while enabling both double glazing capability and reliable moisture management
3Loss of energy
If moisture is allowed to pass through the timber sill to reach the flashing, then drainage can occur, but the timber sill rots from moisture exposure
Solution Approach 1:
The moisture collection function is extracted from the timber sill structure and assigned to a separate recessed area and sill drainage member. These components are specifically designed to collect and channel moisture away from the timber, preventing rot while maintaining drainage efficiency. The timber sill is relieved of the harmful moisture accumulation burden, allowing it to retain its structural integrity
Solution Approach 2:
The moisture that would otherwise rot the timber sill is converted into a controlled flow path through the recessed area and sill drainage member. By providing a dedicated drainage channel, the system transforms the harmful moisture into a beneficial controlled evacuation process, directing water away from vulnerable timber areas through the flashing system. The harm of moisture exposure is converted into an organized drainage benefit
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 sill drainage member effectively prevents moisture entry and rotting of timber sills, simplifies the installation process, offers a guarantee of weather tightness, and allows for the retrofitting of double glazing units, maintaining the timber look while enhancing drainage characteristics.
Implementation Method 1
the upper surface includes drainage means being adapted to drain moisture or fluid from a window sash wherein the drainage means includes at least one recess shaped and oriented to collect and direct moisture or fluid away from the sill drainage member
Data Source
AI summary
A sill drainage member for a window assembly which can include at least one sash. The sash includes a window pane in a frame which can be a single or double glazed window. The sill drainage member has an elongate body with an upper surface and lower surface. The upper surface includes drainage means which is adapted to drain moisture from a window sash. The sill drainage member is adapted to be located and fixed underneath a window sash. A method of installing the sill drainage member with slope blocks and double glazing units is also included and a method of retro fitting double glazed units in wooden sashes.