Chimney Flashing Sealant – Properties, Types & Brands

Here, our goal is to inform you. By reading this article, you’ll find out quite a lot about chimney flashing sealants.

When installing or repairing a chimney, the part of the chimney that projects out of the roof require close attention. Without proper installation, the flashing or point that meets with your roof is likely to leak. Chimneys and leakages don’t mix.

In other words, your chimney installation needs to be watertight.

To make this happen, you’ll need to know more about chimney flashing.

Not all flashing sealants will get you the right results. Thankfully, your chimney technician will know the best product available.

Best Chimney Flashing Sealant Options

There are two classes of sealants used on chimneys.

As the names differ, so do their chemical makeup. However, both sealants will serve the purpose they’re designed for which is to act as an adhesive that blocks out moisture.

Let’s take a look at each and what they’re composed of.

Polyurethane Chimney Flashing Sealants

Polyurethane is among the common chimney flashing sealants you’d find in the market.

This isn’t only used to fix open spaces for leakage prevention but also for a wide range of uses. This chemical product can be used for horizontal joints, as well as in vertical applications.

You’d find polyurethane being used for isolation joints, roofing, gutters, foundation as well as expansion & control joints among several construction purposes. These are only a few as it also has mechanical uses.

Basic Characteristics of Polyurethane Chimney Flashing Sealants

When it comes to the features of this product, it’s quite easy to use as it comes ready to use. In other words, no mixing is required. Polyurethane flashing sealants are best for harsh weather and climatic conditions.

When applied properly, it holds out all forms of moisture ensuring that water doesn’t get through your flashing.

Whatever the joint size you’re looking at, this flashing sealant will adequately serve its purpose.

If you’re worried about its color is different from that of your roof, there’s no need for that. Polyurethane chimney flashing sealants can be painted over to match your roof’s color. It’s also elastic and permanently flexible.

Plus, it’s corrosion-resistant.

  • Type(s) of Polyurethane Chimney Flashing Sealants

There are several products when it comes to the different types of polyurethane flashing sealants.

Among the most popular is the Loctite PL S30 Black Polyurethane Roof and Flashing Sealant. This product has all the characteristics listed above.

Silicone Chimney Flashing Sealants

This is another variation of chimney sealants that are widely used in construction. It’s quite versatile as it can be widely used for a variety of projects including the sealing of chimney flashing.

Silicone flashing sealants mostly come in gel forms.

Like polyurethane sealants, silicone flashing sealants are stable in harsh climatic and weather conditions. This makes it reliable and quite popular for construction work. However, when applied to your flashing, it must be allowed to cure.

It takes time for this adhesive to cure. Curing time ranges from a day to several days depending on its thickness. The thicker it is, the longer it takes to cure. You’ll need some patience to wait out this curing time.

  • Types of Silicone Sealants

Silicone sealants come in various forms. These range from multipurpose, high temperature, and electric grade self-leveling sealants. These come in various forms due to the special adhesive requirements they’re designed to serve.

So, which of these best serves as a chimney flashing sealant?

Electric grade and multipurpose silicone sealants will best serve your needs. Electric grade silicone sealants, they’re designed to withstand the elements. No matter how harsh the weather condition is, this sealant will keep out moisture from getting through your chimney flashing.

True to their name, multipurpose silicone sealants are designed to offer solutions to a wide range of construction projects. This includes sealing chimney flashing. All you have to do is apply it for whatever work you wish to do.

Like electric grade self-leveling sealants, multipurpose sealants are also designed to withstand harsh weather conditions. This will perfectly fit whatever work you wish to get done.

Variants of this product (silicone flashing sealants include American Sealants ASI 5900 Fast Grab Adhesive and Electric Grade Self-Leveling Silicone. There are several other variants you may wish to get.

Best Sealant To Use For Chimney Flashing

A lot of questions have been asked about the difference between polyurethane and silicone chimney flashing sealants. Questions about differences in quality or which is best often arise.

To find the answer, it will do well to look at their chemical constituents.

Over time, polyurethane eventually gives way by breaking down due to UV radiation. For silicone, this doesn’t happen mainly because it’s made of inorganic material. Now, you may be interested in knowing just how long a chimney flashing sealant will serve.

Both types of sealants are designed with an expected lifespan.

For polyurethane flashing sealants, they’re expected to last a decade after which you’ll need to replace them. This isn’t the case for silicone sealants as these last longer. Silicone sealants can serve as long as two decades.

So, does it mean silicone sealants are way better than polyurethane flashing sealants?

Not exactly! Each of these serves a purpose. There are certain advantages when it comes to the use of polyurethane. These products are cheaper since they’re easier to manufacture.

You’ll spend more buying silicone chimney flashing for good reason because they last longer. So, are you on a tight budget? You might want to give polyurethane chimney flashing sealants a try as these are quite affordable.

However, you should know that you’ll need to replace polyurethane flashing sealants more often than silicone sealants. Silicone sealants may have a lifespan doubling or even tripling that of polyurethane flashing sealants.

The decision is up to you. You’ll need to make the decision based on your needs.

Consult Your Technician On The Best Sealant Option For Your Chimney

A chimney installation technician plays a major role in determining what supplies get used in the installation process. By expressing your concerns, you should have a better idea of what’s best and what isn’t.

Chimney flashing sealants have been discussed to this point. We’ve looked at the different types as well as their features and benefits. The disadvantages have also been stated.

You’re now left to decide what to use for your chimney installation.

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