Seismic and thermal movement joints: define the design brief
Define the required movement envelope before choosing a seismic or thermal joint. A product's category name does not replace the structural engineer's design brief.
Selection considerations
Thermal movement and seismic displacement may involve different ranges, directions and service conditions. Record the design opening, closing, lateral and vertical demands where applicable. Ask which condition controls the selected joint at each location.
Compare the full assembly and its transitions, not just a straight sample. At changes of plane, movement continuity can be harder to achieve than along a uniform run. Keep fire, water and finish requirements as coordinated checks. Do not claim that a cover makes a building earthquake-safe; its role is limited to the movement-joint assembly for which it is specified.
Before you specify or order
- Obtain the design movement envelope
- Review intersections and transitions
- Confirm the complete assembly scope
Relevant BULDX catalogue examples
These records illustrate the product types discussed. Compare the full specifications before selecting; listing here does not establish project suitability or make the items interchangeable.
BDX-EJ-FL-RF-100-45-310-P30-N60-AL · Product geometry from the catalogue; a family illustration may be shared by variants. Consult the selected technical documents for dimensions and the approved fixing detail.| Product and code | Selected catalogue fields |
|---|---|
BDX-EJ-FL-RF-100-45-310-P30-N60-ALRecessed Seismic Floor Joint · 100 mm opening · 45 mm heightSeismic Floor Joints |
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BDX-EJ-WC-RF-50-16-150-P38-N38-EPDMRecessed Seismic Wall & Ceiling Joint · 50 mm opening · 16 mm height · EPDMSeismic Wall & Ceiling Joints |
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BDX-EJ-FL-RF-100-70-352-P40-N50-TPERecessed Seismic Floor Joint · 100 mm opening · 70 mm heightSeismic Floor Joints |
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Common question
Can seismic suitability be judged from a large cover width?
No. Suitability depends on documented movement capability, configuration and the project requirements.
References and scope
Product fields are from the BULDX catalogue. Confirm the current selected drawing, supporting performance documents and approved project detail before ordering. External references, where listed, provide background guidance and do not certify these products.