Skip to Content
Back

Avoid These 6 Common Window Caulking Mistakes

A well-done caulking job can protect your home against moisture intrusion, drafts and heat leakage for many years. Completing this task now will make the transition to “cool season-mode” much easier.

Before you begin, consider these common caulking mistakes so you can be sure to avoid them.

1. Not selecting the right caulk

When it comes to caulk, you get what you pay for. For long-lasting protection around your windows, choose a high quality caulk made from silicone or polyurethane.

100% silicone caulk or a mix of silicone and latex, is waterproof, flexible, shrink-proof and will last over 20 years. It is also commonly found in hardware stores. The downside of silicone caulk is that it cannot be painted and can give off a strong odour as it dries.

Polyurethane caulk will last from 10 – 20 years, can be painted over and adheres well. Polyurethane spray foams are heavy duty and tend to expand as they dry. This is a common option for exterior window caulking.

Less expensive options such as butyl rubber or oil or resin based caulks aren’t generally as flexible and won’t adhere to surfaces for as long. Resist the urge to save money on caulk. 

2. Leaving on old caulk

Caulk tends to harden as it ages, usually breaking away from its surface leaving moisture to accumulate beneath. Without sufficiently removing old caulk you risk leaving old moisture on the surface of the window. Use a putty knife or sharp tool to remove it. 

To remove extra-hard caulk, you may choose to apply a caulk remover gel. Leave it on 2 – 3 hours to loosen caulk before scraping. Then clean the surface with a household cleaner or rubbing alcohol and ensure the surface is clean and dry before caulking.

Hint: to find out if you’ve missed any cracks, try the incense test. Hold a smouldering stick of incense against the edges of a window. If there’s a draft, the smoke will be blown out horizontally. If not, it will rise as normal. 

3. Not using the right applicator

The cartridge of caulk you buy from the hardware store isn’t designed to double as a tool for direct application. You’ll need a good quality caulking gun to dispense it properly. When shopping or a caulk gun, look for a model that has a comfortable grip and a smooth plunger rod.

Inexpensive guns that use a racheting plunger tend to apply caulk unevenly, making the job look messy. Cut the nozzle of the caulk cartridge to your desired bead size, pierce the inside seal, then insert into the caulking gun. Seal cracks with caulk at an even, consistent pressure, holding the gun at a 45-degree angle.

4. Applying too much product

If the crack you’re sealing exceeds 1/2 inch wide or 1/2 inch deep, don’t be tempted to simply add more caulk. Instead, fill the gap with a backer rod (a small segment of foam rope), to fill the gap before caulking over. 

5. Skipping tooling

Tooling is the process of smoothing out caulk after it’s been applied. This important step ensures your job is effective and looks neat and professional. Your hands are often the best tool to use for this process. After applying a bead of caulk, run your finger along the bead to ensure it fills the gap.

Dip your finger in soapy water before tooling to make sure your skin doesn’t grab the caulk, or use an ice cube.

Maintaining your windows is one way to ensure your home stays in peak condition through the seasons. Just as fall is a great time to begin extra maintenance procedures, it’s also an ideal time to review your home insurance policy. Are you adequately covered?

Avoid These 6 Common Window Caulking Mistakes

Window caulking, the process of sealing off cracks around a window with a waterproof sealant, is a simple job with a big pay-off.