Problem Solving Forum
August 26 - August 30, 2019
How do you keep sealants in control joints from cracking or separating from the substrate?
Zenith Czora of Durotech Industries, Inc. on
August 28, 2019:
To achieve the maximum service life of sealants an ...read more To achieve the maximum service life of sealants and to keep the sealant from cracking and even separating from the substrates, the following do's should be followed: 1. First ensure that the right type of sealant is used and its compatibility with the substrate is checked. Incompatibility will cause an adverse reaction at the sealant-substrate interface. The correct type of sealant should be identified for its appropriate application and performance. Sealant should be flexible enough to accommodate joint movements but also must recover to its original size during joint contraction. 2. Proper surface adhesion is the key to good adhesion. The joints' surfaces must be free of moisture, dust, loose aggregates, dirt and other contaminates. 3. Sealant primer can be applied on the surface of the joints to ensure good bonding of sealants to the substrates. 4. When using a multi-component sealant, all the components should be properly mixed at the required ratio. 5. Sealant must be applied at a correct ratio to depth and width of the control joints and there should be no excessive joint movement during the curing of the sealant. When movement occurs during the initial cure cycle of the sealant this will cause sealant's surface wrinkling and cracking resulting in cohesive sealant failure. 6. Sealant should be adequately tooled to ensure good contact of sealant and the substrate.
Hugh O'Neill of Fastrack Contracting Ltd on
August 27, 2019:
Use a bond breaker and ensure sealant is the right ...read more Use a bond breaker and ensure sealant is the right dimensions: width about 1.5 times the depth.