Caulking Identification

Caulking Identification

A simple guide to identify the exterior caulking on your property and how it will affect your next sealant project.

Are you starting a sealant project soon? What do you think of before the project starts? One of the many missed thoughts isn’t “what is the best product to use?” but, “which product will work best on my property?” The answer to that question starts with what’s already there.

Caulking, like everything else, has many variations. These variations can vary by the age of your property to the type of property you have. These variations in caulking come with many different properties and limitations. By defining what type of caulking you have on your property, you will get a clear outline of the steps necessary for the removal, surface preparation and installation. This will help you understand how the project will progress, how the work will affect the residents and the overall look of the final product. Let’s start with the most common types of caulking we find.

Mastic

Is your property 15+ years old? Is the caulking original to the construction? If you’ve said yes to both, there’s a good chance you have mastic. Don’t worry! It’s not terminal, just tricky. This inflexible, hard to the touch caulking is a thing of the past. This caulking provides zero movement around the opening, which over time causes this caulking to split, most commonly from the brick or substrate around the window or door. If you have this caulking, it is time to remove and update. The tricky thing about this removal is its very hard make up. Power tools and safety glasses are a must here because when it breaks, it will break into a million pieces. This caulking in our opinion, is the most stubborn to remove and takes the longest. Your residents will appreciate the update though, the most common leaks and drafts have been due to this caulking failing.

Thermoplastic

For any manager or owner that has had their window frame replaced, it’s a safe bet that the installer used thermoplastic caulking. This rubber-based caulking, commonly seen in cartridge form shown here, is an inexpensive style of caulking that comes in a very wide variety of colours. These factors make it the most popular caulking for any window installer company. There are downsides to this caulking. This material will almost always fail an adhesion test. This does make it easy and fast to remove, once a contractor gets a hold of it, they can usually pull the entire caulking bead out around the perimeter of your door or window with little to no residue left on the substrates. This material is also installed in a very small bead, with very little adhesion to the new window or door frame. This allows the contractor who is removing and reinstalling the ability to keep the new caulking beads small. This material is also known to split, like the mastic, due to its rigidity. Although inexpensive, it is not a good choice for a long-lasting sealant.

Silicone

Silicone is the most common material associated with caulking. It is found in newer built homes and buildings, as well as a go to for contractors who repair leaks. This rubbery, not paintable, smooth to the touch sealant will not come out in one piece if installed correctly, it will need to be cut out with power tools for efficiency. The right silicone can have long lasting adhesion on your property. There are two things to think about after finding silicone sealant on a site:

  1. Silicone sealant residue will not remove fully from a substrate. After removal, there will still be residue. What this means is that the contractor replacing the caulking will have to make the bead bigger, to adhere properly. If kept the same size, you are relying on the silicone residue to hold onto the new silicone, when the better option is fresh substrate. Your bead will increase in size by about ¼”, this should be communicated to all parties involved before the project starts.
  2. Silicone will not adhere to other types of sealants. If a different kind of sealant is found on your site, there are only a couple options. After removal, a bigger bead must be installed. Complete removal of existing material from substrate involving extra prep work such as grinding, chemical solvents or adding metal flashing to give fresh substrate for adhesion.

Polyurethane

If your caulking is painted without cracks in it, or is firm to the touch, you’ve got polyurethane. This caulking is commonly found around painted surfaces, in expansion joints around a building or in parking structures and underground garages. This caulking will also need to be cut out with a power tool. Although slightly stiffer and harder to cut out, polyurethane caulking follows similar rules to silicone.

  1. Polyurethane sealant residue will not remove fully from a substrate. After removal, there will still be residue, what this means is that the contractor replacing the caulking will have to make the bead bigger, to adhere properly. If kept the same size, you are relying on the polyurethane residue to hold onto the new caulking, when the better option is fresh substrate. Your bead will increase in size by about ¼”, this should be communicated to all parties involved before the project starts.
  2. Polyurethane will not adhere to silicone. If a different kind of sealant is found on your site, there are only a couple options: After removal, a bigger bead must be installed. Complete removal of existing material from substrate involving extra prep work such as grinding, chemical solvents or adding metal flashing to give fresh substrate for adhesion.

When you identify the caulking on your site, expectations and limitations can be set in place prior to a job starting. This will help mitigate any adhesion or installation issues that may arise. This simple guide will help you confidently start the sealant replacement and pave a way to a successful project.

After identifying the sealant currently on your site, you’ll need to decide what product to use! Please check out our next blog post “Choosing the right caulking” to continue a successful path to your next sealant replacement project.

Scroll to Top