In modular construction, precision and assembly speed must go hand in hand with peak insulation performance. One of the critical engineering challenges is ensuring the integrity of joints between modules. Even the smallest leak in the building envelope can lead to structural degradation, energy loss, and moisture-related issues.
The key to success lies in selecting materials that maintain elasticity for decades. In this context, butyl sealants represent the industry standard due to their impermeability to gases and water vapor, combined with excellent adhesion to various substrates.
Challenges in Sealing Modular Systems
Designing joints in prefabricated systems differs from traditional construction primarily due to the structural dynamics. Modular joints must:
-
Compensate for dimensional tolerances of prefabricated elements.
-
Withstand vibrations occurring during transport and crane assembly.
-
Guarantee the continuity of air and vapor barriers.
Applications of Butyl Sealants in Various Forms
Butyl is a synthetic rubber that does not harden (it is permanently plastic), making it ideal for dynamic joints. Depending on the specific architectural detail, different forms of this material are utilized:
1. Butyl Tapes (Strips)
This is the most popular form of sealing for flat contact surfaces. Butyl strips are indispensable for sealing lap joints, such as those found in wall panel assemblies or roofing.
-
Advantage: Constant sealant thickness across the entire length of the joint.
-
Application: Sealing vapor barriers, roofing membranes, and flange connections.
2. Butyl Cords (Beads)
Round-profile cords are used where there is a distinct gap or a pre-formed groove.
-
Advantage: Excellent void filling while maintaining high initial grab (tack).
-
Application: Sealing ventilation ducts within modules and vertical joints between curtain walls.
3. Extrudable Butyl Compounds (Cartridges/Bulk)
Plastic masses applied via sealant guns allow for great flexibility in filling irregular shapes.
-
Advantage: Ability to reach hard-to-access areas and apply material into sockets with variable geometry.
-
Application: Sealing MEP (mechanical, electrical, plumbing) penetrations and reinforcing corner seals in modules.
Key Principles for Designing Butyl Joints
For butyl technology to be fully effective, the designer must consider three fundamental pillars:
-
Substrate Cleanliness: Butyl has phenomenal adhesion, but only to surfaces free of dust and grease. Factory conditions (off-site) make it easier to maintain this technological discipline than on-site.
-
Mechanical Compression: Butyl sealants perform best in compression joints. When designing a detail, include a clamping element (e.g., a flashing or screws) to keep the compound under constant pressure.
-
Width-to-Movement Ratio: The width of the tape or cord should be selected so that the continuity of the layer is not compromised during predicted thermal movements of the structure.
Designing leak-proof joints in modular construction requires a systemic approach. Utilizing butyl tapes, cords, and extrudable compounds allows for the creation of a barrier that is both durable and easy to apply in the controlled environment of production halls. By choosing butyl solutions, you invest in the building’s longevity and minimize the risk of claims related to thermal bridging or moisture ingress.