Factors to Consider When Choosing the Correct Sealant for your Restoration Project
In a previous blog post we discussed How to Identify Causes of Sealant Failure in Restoration Construction. This post detailed the seven common causes of sealant failure that can occur in restoration construction. That list includes aging, incorrect sealant selection, inadequate surface preparation, excessive joint movement, early joint movement during sealant cure cycle, improper sealant application, and substrate incompatibility. In addition to identifying the causes of sealant failure, we also highlighted some ways to mitigate them. After identifying the cause of the failure, it is time to choose a replacement sealant and begin the restoration work. For this week’s blog post, we take a look at some of the factors to consider when choosing the correct sealant for your restoration project.
Identify Failed Sealant Type
Properly identify the failed sealant type in order to accurately access the causes of failure and appropriate restoration sealant.
The sealant manufacturer (if known) can assist in identifying the failed sealant type i.e. silicone, polyurethane, polysulfide, etc. through laboratory analysis of sealant samples.
If the incorrect sealant type was originally installed, ensure the appropriate replacement sealant type is identified prior to reapplication.
Avoid Recurring Failures
Choosing the correct replacement sealant is critical when restoring a failed sealant joint in order to avoid recurring sealant failures.
Sealant selection will be determined by the type of failure/s experienced on the project i.e. excessive joint movement, incompatibilities, etc. Existing sealants can also have influence over choice of restoration sealant.
Sealants that have failed due to excessive joint movement must be replaced with a sealant that can accommodate the actual joint movement occurring at the project. A sealant upgrade, with respect to movement class, will be required in these situations.
Sealants that have failed due to early joint movement during sealant cure cycle must be replaced. The repair process involves either selection of a sealant that will perform under adverse conditions of early movement or waiting for extreme conditions to subside before undertaking repairs.
Any sealant / substrate incompatibilities must be clearly identified and the appropriate testing must be conducted in order to determine the correct restoration sealant.
If poor surface preparation or omission of sealant primer has caused the sealant failures, the sealant should be reinstalled per the manufacturer’s surface preparation and priming guidelines.
If the failed sealant has significantly aged and has reached its maximum service life, all affected sealant should be replaced.
If an improper sealant application was identified, the identical or appropriate alternate sealant may be reinstalled provided that the manufacturer’s published installation procedures are strictly followed.
Interior or Exterior
Careful consideration and review of manufacturer’s data sheets should be carried out in order to determine proper sealant for application.
Movement Capabilities (Please See Photo #12 Below)
A sealant’s designed movement capabilities (extension/compression) are typically published in the manufacturer’s product literature.
Be sure to choose a sealant that will accommodate the anticipated joint movement occurring at the project.
Color and Paintability
Sealant color may or may not be vital to the project owner. Be sure to select a sealant that is available in the color choice required for the project.
Most sealants are paintable with the exception of silicone-based sealants. If the sealant is to be painted, be sure to choose the correct sealant and compatible paint finish. Consult the manufacturer for required sealant cure times prior to painting