joint sealant guide

If you are planning to use a sealant in your next project, you need to make sure you pick the best one for the job.

What Is a Joint Sealant? 

A joint is where two different materials meet. A joint sealant is a substance used to seal or close the gap between these two materials. Its purpose is to prevent fluids, air, and other substances from getting through the gap while also allowing for limited movement. Joint sealants have several applications, including commonly in construction and building design.  

Choosing the Right Joint Sealant 

Because a joint is a vulnerable part of a structure, the sealant for the joint needs to be the right product for the job or the consequences could be serious. With so many options, it can be hard to know here to start, but our guide to picking the correct joint sealant can help you make the right choice for your needs.  

Step 1: Consider the Requirements of the Job 

There are so many different types of joint sealants with different applications. Before you start thinking about which joint sealer to use, you first want to have a clear understanding of what you need from your sealant. When choosing a joint sealant, it is important to consider the following: 

  1. What type of substrates will be used? 
  2. Will the sealant be used on the interior or the exterior? 
  3. Will the joint be subject to any movement or vibration? If so, how much? 
  4. Does the sealant need to have any special resistances for the environment such as temperature extremes, moisture, UV light, or chemicals? 
  5. Will you be able to apply it quickly or will you need a longer open time? 
  6. Are you attempting to bond any difficult materials? 
  7. Will you need to paint over the sealant? 

Only after you have answered these questions can you start to get a better picture of which joint sealant you need.  

Step 2: Review the Types of Sealants to Narrow Your Choices

After you have all the details on the requirements of the job, the next step to choosing the right product is to determine the joint sealant material that will work best. There are several different types of sealants available with different properties and pros and cons.  

  1. Latex– Latex sealants are water-based sealants that are inexpensive and easy to apply. They are easy to paint over, especially with latex paints. Latex joint sealants are a good choice for interior jobs, but their uses are limited. 
  1. Acrylic– Acrylic sealants are solvent-based sealants. They are good for submerged joints, have reasonable UV resistance, and are easy to paint. A con of acrylic joint sealants is that they are not suitable for a lot of movement, so they tend not to do well on exterior projects.
  1. Butyls– Butyl adhesives are synthetic rubber materials that have excellent adhesion with the majority of substrates, but they are not suitable joint glue for a lot of movement. They work well for interior projects but are hard to paint and should be kept away from any source of UV light. See this butyl sealant for acoustical and vapor barriers as an example.
  1. Polysulfides– Considered high-performance sealants, polysulfide joint sealants are often used for industrial applications for interior and exterior purposes. They are especially favored in situations where chemical resistance is required or the joint is submerged. If your joint is going to be experiencing cyclic motions, then it would be best to avoid polysulfide sealants.
  1. Silicones– Silicone sealants are highly versatile and can be used in a wide range of applications including for both interior and exterior projects. Because they are particularly durable and remain flexible over time, they are an excellent choice for sealed joints that are likely to undergo large amounts of motion. They also have a high UV resistance. The downside to silicone sealants is that they are unsuitable for submerged applications and are also not paintable. They are poor choices for brickwork but otherwise bond well with most other materials.
  1. Polyurethanes (PU) PU sealants are the most versatile. The only applications they are unsuitable for are those involving glass. They are resistant to wear, paintable, and perform well on joints that have high levels of movement. The cons of polyurethane sealants are that they can be difficult to apply, and not surprisingly, they are the most expensive joint sealant.

Step 3: Think About Your Budget  

Once you have narrowed down your joint sealant glue selection to one or two materials, the next step is to think about your budget. While an inexpensive joint sealant may be enticing, it may not hold up as well and could fail over time if it is the wrong product for the job. On the other hand, the most expensive choice may not be feasible with your budget.  

Once you have taken into account these different considerations, you should be much closer to finding the right joint sealant for your needs.  

flexible connector

Case Study

Let’s try an example. You need a stainless-steel pipe thread sealant for a joint that will be inside a pneumatic drill. 

Step 1: Consider the requirements of the job.  

You conclude that the sealant needs to work in exterior settings and be resistant to UV. It will be subject to large amounts of movement. The seal must also be durable and flexible.

Step 2: Review the types of sealants. 

From the requirements, it seems clear you will need a high-performing thread sealant. Because of the heavy movement, your choices are limited to either silicone or PU sealant. 

Step 3: Think about your budget.  

PU sealants tend to be more expensive, and you just don’t think you have the budget for it. You decide to go for a silicone option that is marketed as being especially resistant to vibration.  

Let Us Help You Choose the Right Joint Sealant

expert advice

If you have gone through these steps to pick a joint sealant but are still unsure of what to choose, that is okay. We want to help. Our customer service representatives are sealant experts who are happy to guide you to the right sealant solution for your job and budget. Give us a call at (855) 437-7700 or fill out a contact form today.

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