Case 1
- Introduction
- Causes of Defects
- Good Practices
- Standards
- Maintenance and Diagnostics
- Remedial
- Similar Cases
- References
Good Practices
Common sealant failures involve loss of bond to the substrate, separations within the sealant, loss of flexibility, and aging and weathering including chalking, discoloration, cracking, wrinkling, erosion, or excessive softening. Managers can use the following suggestions as a guide to successful sealant selection, installation and evaluation:
Proper joint geometry can be one of the most critical factors in sealant performance. Removing a small section of sealant can provide a means of checking. In general, for typical joints, sealant should be at least 1/4-inch deep and no deeper than the joint width.
Surface preparation and the use of primers is also a key factor. Joint substrates should be clean and dust-free. Certain substrates may require a primer.
Workers should use a sealant only within its shelf life. For multi-component sealant, proper proportioning and mixing of sealant components is essential. Sealant should only be installed and cured during appropriate weather conditions. Joint surfaces should be dry and frost-free, and installation during excessive heat or cold should be avoided. Before installing sealant, quality- control testing is useful in avoiding problems, with special attention to adhesion and staining.