What Affects Deflection
Deflection depends on pane dimensions, span, glass thickness, support condition, load magnitude, glass build-up, and laminated glass assumptions.
SLS Review
Serviceability checks are normally reviewed separately from ULS stress checks because a pane can be strong enough but still too flexible for the project brief.
Support Conditions
Four-edge, two-edge, and one-edge support conditions can produce very different deflected shapes and governing spans. The support model should match the real framing detail.
Wind Load and Facade Glass
For structural glazing and facade panels, wind pressure or suction can govern deflection. The same pane may pass stress checks while still needing a serviceability review.
Laminated Glass Deflection
Laminated glass behavior depends on ply thickness, interlayer assumptions, load duration, and the design method used for the project.
Using VitraLab
Enter the pane size, build-up, support condition, and load values, then review SLS deflection output, utilization ratio, warnings, and project assumptions.
Example Deflection Checks
Example VitraLab deflection result images for horizontal laminated glass, vertical DGU glass, and one-edge supported balustrade glass.
Frequently Asked Questions
Why is glass deflection important?
Deflection affects appearance, movement, drainage, comfort, sealant behavior, and project serviceability requirements.
Can glass pass stress but fail deflection?
Yes. A pane can have acceptable strength utilization while still exceeding the selected serviceability deflection limit.
Which inputs matter most for deflection?
Span, thickness, support type, load magnitude, aspect ratio, and laminated glass assumptions are usually the most important inputs.