What are the reasons for Silicone Joint failure?

There are mainly three types of Silicone Joint failures namely-

• Failure due to loss of Adhesion – failure of the sealant to adhere along the joint line of the surface, to which it is attached, causing it to break away from the joint.
• Cohesive Failure– occurs when the sealant fails to hold together. Cohesive failure can take the form of a crack or tear in both the horizontal and vertical directions of the sealant.
• Substrate Failure– It is not a failure of the sealant, but of the surface to which it is supposed to adhere.

The main reasons for Silicone Joint failure are –

• When the wrong silicone is used for the joint.
• When the joint width and/or depth are too great or too small.
• Excessive movement in the joint sealed.
• Contamination of surfaces due to ‘dirty’ materials. Before application of the sealant, care should be taken to clean the surfaces properly.
• Poor gunning and application technique.
• Poor quality sealant.

It is therefore very important to consider all of the above factors when sealing a joint and taking all the necessary precautions before application so as to prevent any kind of joint failure.