December 16, 2019
As most building managers / building engineers and building owners know, maintenance cost $$$$$. However, have you ever stopped to calculate how much additional you might pay in a year’s time in heating and air conditioning costs alone if your joint sealants are deteriorated and no longer perform as they should? Scheduled visual inspection is a simple method of determining how the sealants are performing. Water intrusion is a much more destructive method of determining how your sealants are performing.
Once you decide that removing and replacing the joint sealants is necessary you, then have to decide whether to replace with urethane or silicone. The sealant selection can be a daunting process and is usually best left to the professionals. Selection should never be made on a cost basis alone. Several important factors should be considered including performance criteria, longevity of the sealant and manufacturer’s warranties. Some silicone sealants are now warranted for 20 years. Another very important factor is to use a professional, qualified contractor. Many will advise you to caulk over what is already in place: WRONG. You can never make a bad joint good by simply smearing new caulk over old. All existing caulk should be cut out, the joint cleaned / prepped, primer used if required by the manufacturer, backer rod installed to prevent three-point adhesion and the sealant installed and tooled. Only then would you have an acceptable joint.
After proper application and curing, an in-place field adhesion evaluation of cold applied sealants should be performed. One such test is “Standard Guide for Use of Joint Sealants” or ASTM C 1193. This document lists four methods for testing sealant adhesion:
- Method A – Field-Applied Sealant Joint Hand Pull Tab
- Method B – Exposed Surface Finish Hand-Pulled Tab
- Method C – Field Applied Sealant Joint Hand-Pulled Flat
- Method D – Water Immersion Test
Of all of the above, Method A is by far the most popular. Although this is a destructive test and the portion of the joint sealant will have to be repaired. Approximately a 3” tab is cut from the cured joint and then “hand-pulled” at 90 degrees to the joint. High resistance to pull, and a cohesive failure whereas the sealant tears from itself to remain on the sides of the joint, will show evidence of a properly adhered sealant to the substrate. Testing and certification is a very important part of our industry. Watertight is committed to maintaining vendor certifications to keep up with the latest innovations in product technology.
Remember, you are ultimately responsible for the condition, and environment, of your building. The little dollars can quickly add up to large dollars if regular maintenance is not part of your in-house plan. If you have any questions or need additional information on building sealants, or any other aspects of your building exterior please call us at Watertight Systems. We will be happy to point you in the right direction.