Window Sill End Profile with Plaster Mesh for Thermal Expansion
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Solution Overview
Problem
Existing methods for installing external window sills face issues with thermal expansion due to temperature fluctuations, leading to adhesive failures and moisture ingress, particularly in thermal insulation composite systems (ETICS), where rigid connections fail to compensate for linear expansion, resulting in cracks and impermeability to driving rain.
Innovation Solution
The end profiles are equipped with a plaster mesh on their upper flange, integrated into the masonry with the plaster mesh in contact with the window reveal, and fastened to the lower window sill, allowing for absorption of linear expansion through a seamless, permanently sealed transition, with an insulating wedge preventing condensation and ensuring a clear separation of trades during installation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If rigid adhesive connections are used between end profiles and plaster, then structural stability is improved, but thermal expansion compensation deteriorates
Solution Approach 1:
The connection system is divided into two functional segments: a rigid adhesive connection between the end profile and plaster for structural stability, and a separate deformation capability of the end profile itself (bulging upwards) for thermal expansion compensation. This segmentation allows each component to fulfill its specific function without compromising the other.
Solution Approach 2:
The end profile is designed to change its geometric parameters (shape) in response to thermal expansion. The profile can deform by bulging upwards, changing its cross-sectional dimensions and form, thereby accommodating thermal expansion while maintaining the rigid adhesive connection to the plaster.
2Adaptability or versatility
If soft material strips are added to allow expansion, then thermal expansion compensation is improved, but compressive stress transmission worsens
Solution Approach 1:
The end profile itself acts as an intermediary element between the rigid plaster structure and the expanding window sill. By designing the end profile with inherent deformation capability (bulging upwards), it mediates the thermal expansion forces without requiring additional soft material strips that would transmit compressive stresses to the plaster.
3Stability of the object's composition
If end profiles are rigidly connected to window sills, then structural stability is improved, but crack formation due to thermal expansion worsens
Solution Approach 1:
The connection system transitions from a completely rigid static connection to a dynamic system where the end profile can deform (bulge upwards) in response to thermal expansion. This dynamic capability allows the structure to adapt to temperature changes while maintaining overall structural stability, preventing crack formation in the plaster.
4Adaptability or versatility
If expansion joints are filled with flexible plastic strips, then thermal expansion compensation is improved, but labor intensity and assembly complexity worsen
Solution Approach 1:
The end profile is designed with self-service capability for thermal expansion compensation. Instead of requiring manual installation of flexible plastic strips in expansion joints, the end profile itself possesses the deformation capability (bulging upwards) to compensate for thermal expansion automatically, simplifying the assembly process and reducing labor intensity.
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
This solution provides a permanent, tight seal resistant to driving rain, absorbs linear expansion caused by temperature fluctuations, and prevents moisture damage, ensuring a smooth and time-saving construction process by decoupling the window sill from the window reveals, thus maintaining functionality over time.
Implementation Method 1
weather-related temperature fluctuations can cause disadvantages, namely thermal expansion in the transition area between the plaster and the end profiles. In winter, the possible temperature differences are between plus 40°C in the midday sun and minus 20°C at night, i.e. in the order of approx. 60°C. The resulting expansion of a light metal window sill is in the range of several millimeters.
Implementation Method 2
The end profiles are glued to the lower window sill as well as to recesses in insulation panels of a thermal insulation composite system (ETICS) or the masonry of the window reveals using an adhesive or caliper gauge.
Data Source
Figure 1
Figure 2a~2b
Figure 3
AI summary
The method involves providing an end profile (1) with a surface- or concealed fabric (14) at its upper profile flange (5) and positioning an end profile with the attachment of the concealed fabric to a window reveal (21) in the brickwork. The end profile is fixed on the lower window parapet (19) over its lower profile flange (6). The end profile is plastered with the plastering of the window reveal. A window sill is inserted in the end profile. An independent claim is included for an end profile with a longitudinal edge.