How to Select the Right Building Sealant for Your Project
Sealants are critical components of safeguarding the integrity of a building envelope. They come in many different formulations with various performance capabilities, and installers need to know a lot of technical information to make the right choice for their application.
Among the most important considerations are substrate materials, joint construction and movement as well as sealant performance attributes. Keeping these factors in mind will help you ensure the longevity and safety of your building.
Durability
Sealants are a critical component in safeguarding the building envelope. They come in many different formulations with varying performance capabilities. It’s important to understand their basic characteristics and functions before selecting one for your project.
Durability refers to the ability of a sealant to maintain its strength and integrity under repeated environmental strains. These can include ultraviolet radiation, heat, moisture, temperature, cyclic movement, movement during curing and biodegradation.
The durability of sealant depends on the material’s properties, including adhesive strength, cohesive strength and recovery ability after deformation. The sealant’s modulus (hardness) and elasticity (stiffness) also affect the bonding ability of the sealant. Adhesive strength is the most important property for sealing, because it ensures that the bond between the sealant and substrate remains intact and strong despite tensile forces.
A sealant’s adhesive strength is often measured by peel testing and it must meet or exceed a specified level to pass a standard. For example, ASTM C920 requires that a sealant should not lose more than 25% of its adhesive bond during a peel test.
Adhesion testing is an important part of the design process for building projects. It allows the user to Building Sealant see whether a sealant adheres well to various substrate materials, especially in moving joints. It can be used to identify areas where a primer may be required to promote adhesion and improve performance.
Some sealants can also be tested to determine their resistance to high temperatures. Temperature can cause sealant materials to change their properties, which can make them less effective in certain applications and can lead to failure. This is particularly true of sealants that are used around hot pipes or in buildings in a warm climate.
It is essential to know the amount of heat that a sealant can withstand in use and how long it will last at those temperatures. A manufacturer may not provide this data publicly, but it can be obtained by contacting them and asking for the endurance tests for their product at different temperatures.
Several standards can be used to measure the durability of a sealant, but some are more relevant than others. ASTM C1589’s Procedure C, which combines outdoor weathering and cyclic movement, is becoming increasingly popular among engineering firms and contractors who wish to determine how sealants perform for themselves rather than simply relying on manufacturers’ data sheets.
Moisture Resistance
Moisture resistance is an essential consideration in the life cycle of any product and even more so with building sealants. The best way to assess the moisture resistance of a given product is to ask the manufacturer if there are any moisture test or performance specifications for that product. Depending on the application, this may involve a variety of tests that entail the use of various materials in conjunction with one another. The manufacturers with the most experience are usually up to the task of providing you with this data. The moisture test is a must as is a good quality coatings tester and the results can be used to make the most informed decisions possible on your next project.
The top notch product will provide you with the moisture proofing that your building deserves and will also stand the test of time. If you are unsure of where to start when it comes to choosing the right moisture resistant coating for your next project, contact us and we will be happy to help you make the right selection.
Adhesion
The ability of Building Sealant to adhere to the substrates of a joint is extremely important. It determines the long-term durability of the sealant and, therefore, the longevity of a building. The adhesion properties of a sealant include adhesive strength, cohesive strength, and modulus of elasticity.
Adhesive strength refers to the ability of a material to hold itself together under tensile stress. A material with a low adhesive strength will not be able to provide adequate joint integrity. The adhesion of a sealant depends on the substrates, the type of sealant, the joint configuration, and proper application.
Cohesion, on the other hand, is the tendency of two particles or surfaces to cling to one another, such as the water strider bug (below) that uses surface tension to keep its body afloat on the surface of water. It also refers to the tendency of dissimilar materials to cling to each other, such as the ability of wood and metal to bond together.
This process of attachment occurs primarily in a liquid, but can also occur in a solid, such as the movement of a drop of liquid on a flat surface. As a result of interfacial tension between the liquid and the solid, cohesion is influenced by the wettability of the liquid and the interfacial energy between the materials.
In general, lateral adhesion between two objects or materials is much stronger than normal friction between two solids. In this situation, the object will stay in contact with the surface until enough energy is applied to release it.
The adhesive and cohesive properties of a sealant are determined by its chemistry and polymer type. For example, urethane sealants are generally more Building Sealant durable than silicone sealants. However, urethane sealants may lose their performance characteristics when subjected to continued exposure to water.
If a manufacturer claims unprimed adhesion in their data sheet then the test for adhesion must be done to job site materials, not standard test substrates. This will ensure that a sealant with adequate adhesion is the product being used on the jobsite.
Flexibility
In a building application, the ability of a sealant to accommodate movement under normal conditions is essential. This can be a function of temperature and/or humidity. It can also be a function of the type of material used to manufacture the sealant, or the design of the joint itself.
The best way to determine how well a particular sealant can perform under the most demanding conditions is to ask the manufacturer. The manufacturer should be able to provide information about the most suitable materials to use in a given application, as well as recommendations for proper installation methods and curing times.
For example, a liquid applied sealant should not be installed during freezing weather. This can negatively affect the performance of the product. It is also recommended that the sealant be applied in a clean and dry environment with no other moisture present on the surfaces to be sealed.
Another way to gauge the performance of a particular sealant is to look for industry standard test methods and standards. The most reputable manufacturers have test laboratories to conduct these tests and can often provide recommendations about the best sealant for a particular application. In addition to the standard tests, the manufacturer should be able to provide recommendations about appropriate curing times for a variety of ambient temperatures and moisture levels. The company should also be able to recommend proper application practices such as applying the sealant in stages and using an appropriate type of cleaning solution. Finally, the manufacturer should be able to provide a list of applicable industry codes and standards.