How to properly caulk or reseal your window frame

Caulk is a flexible material used to seal air leaks through cracks, gaps, or joints less than 1-quarter-inch wide between stationary building components and materials. For components that move — doors and operable windows, for example — weatherstripping is the appropriate material.

Before caulking air leaks in an existing home, you will need to detect the leaks and assess your ventilation needs to ensure adequate indoor air quality. In addition to sealing air leaks, caulking can also prevent water damage inside and outside of the home when applied around faucets, ceiling fixtures, water pipes, drains, bathtubs, and other plumbing fixtures.

Selecting Caulking

Most caulking compounds come in disposable cartridges that fit in half-barrel caulking guns (if possible, purchase one with an automatic release). Some pressurized cartridges do not require caulking guns.

When deciding how much caulking to purchase, consider that you’ll probably need a half-cartridge per window or door and four cartridges for the foundation sill of an average home. Caulking compounds can also be found in aerosol cans, squeeze tubes, and ropes for small jobs or special applications.

Caulking compounds vary in strength, properties, and prices. Water-based caulk can be cleaned with water, while solvent-based compounds require a solvent for cleanup.

Applying Caulking

Although not a high-tech operation, caulking can be tricky. Read and follow the instructions on the compound cartridge, and remember these tips:

  • For good adhesion, clean all areas to be caulked. Remove any old caulk and paint, using a putty knife, large screwdriver, stiff brush, or special solvent. Make sure the area is dry so you don’t seal in moisture.
  • Apply caulk to all joints in a window frame and the joint between the frame and the wall.
  • Hold the gun at a consistent angle. Forty-five degrees is best for getting deep into the crack. You know you’ve got the right angle when the caulk is immediately forced into the crack as it comes out of the tube.
  • Caulk in one straight continuous stream, if possible. Avoid stops and starts.
  • Send caulk to the bottom of an opening to avoid bubbles.
  • Make sure the caulk sticks to both sides of a crack or seam.
  • Release the trigger before pulling the gun away to avoid applying too much caulking compound. A caulking gun with an automatic release makes this much easier.
  • If caulk oozes out of a crack, use a putty knife to push it back in.
  • Don’t skimp. If the caulk shrinks, reapply it to form a smooth bead that will seal the crack completely.

The best time to apply caulk is during dry weather when the outdoor temperature is above 7.2°C. Low humidity is important during application to prevent cracks from swelling with moisture. Warm temperatures are also necessary so the caulk will set properly and adhere to the surfaces.


If we can’t fix it…

We have affiliates who can! Glass cleaning, glass replacement, full window replacement, renovation contractors, snow removal, even auto glass and car detailing and that’s just the start! We started The Fog Fix with a goal to become a preferred consultant for your home. Show me your foggy window, but be sure to tell us what else you need, or which contractors you swear by. By letting us know what features you want for your home, we are able to reach out to our trusted network of service and construction professionals. Even if we can’t fix it, we want to make sure you are glad you’ve called The Fog Fix.

How does defogging work?


The Fog Fix Defogging happens onsite and we leave the glass in the frame. There is no dust or mess inside your home. Our technicians repair 95% of windows from the exterior. The repair requires the installation of a membrane on the exterior of the glass over a tiny hole. The Fog Fix positions this membrane in discrete corners of the window. The result is a clear window.

Thermal Pumping

The thermal pane window behaves like a miniature greenhouse. Dry air between the glass expands and contracts with the weather and sunlight. This pumps air in and out of your windows. Contrary to popular belief, window seals are semi-permeable, not hermetic. Manufactures install water absorbing pellets in the outside rim or spacer bar. These pellets in the spacer bar prevent moisture from entering the airspace. After time these pellets become saturated. When the pellets become saturated water starts showing up between the glass.

Windows bow inwards while cooling off.

You may have seen silica gel in your shoes!


When is the best time?

The defogging process is a permanent solution to the fogging problem. The sooner we repair your window, the better the results. The moisture will leave permanent stains after time. All glazed, non-tempered windows can have the moisture removed. If the window fog persists for a long time, deposits may have formed on the inside glass surfaces. If mineral deposits will bake on to the inside surface of the glass. We can still dry out the window but those stains will remain.

How do you do it?

How does The Fog Fix restore windows? Our technician inspects each piece of glass. The tech advises each customer of the condition and expected results after restoration. All service work happens on premise, with little disruption. Our technician arrives equipped with specialized tools and equipment. Glass units are most often serviced from the outside of your home. We install two to four tiny holes in the corners of the outside glass, then cover them with membranes. We use a high speed, lubricated diamond drill. All service work occurs through these holes.

Proven technology

Our proprietary membrane allows the air pressure and humidity to equalize. This prevents further moisture accumulation. Defogging is the proven solution to moisture between panes of glass and has been for many years. The restoration process is a modern adaptation of proven technology. Defogging is the permanent solution to the problem of failed insulating glass units.

Contact Us Today!

Does defogging work with all windows?

While we can fix 80% of windows, unfortunately some of the windows are either too far gone or can’t be drilled through.

Tempered Safety Glass

Industry insiders call this mark “the bug”.

The first example of a window we can’t fix is safety glass. Patio doors and other windows at a higher risk of breakage are required or designed to be made from tempered glass. This glass has extremely high surface tension and if we dry to drill through it, it makes a very loud sound before it breaks into a thousand tiny pieces! You’ve seen this in car windows and bus shacks likely. All tempered glass should have a stamp in one of the corners that says “TEMPERED”.  We can’t fix it, you should replace the glass with one of our partners.

Spacer Bar Corroded

The second example of a window we can’t fix is one that has completely a rusted or rotted spacer bar (very obvious). While we can get the moisture out, it may return. In this case your seal really has failed because of moisture left in the window over a period of time. We can attempt a defogging but we will recommend replacement at this stage.


Then there are the windows that we can fix, but will produce less-than-perfect results. These windows have white streaks and staining inside. This is caused by the moisture in the glass dissolving the spacer bar desiccant. When that desiccant dissolves it forms silica-scale on your glass. This will fade with a defogging but it will not disappear. While defogging is still the most cost-effective solution to get the R-Value back in the window, if you want the white streaks gone you should replace the glass.

Moisture you can touch

We can’t fix the weather! Similarly we can’t fix the environment inside of your home. If all of the moisture is something you can touch, the humidity in your home is probably too high. You can try this one trick to see where the fog is.

One weird trick to tell if your window seal is broken.

You think you’ve seen the fog, but you’re not quite sure. Do you wait until winter again? You don’t have to actually. All you need is elbow grease and a small piece of ice.

Apply the ice cube to the window

Hold a rag under the ice to catch the melt-off and rub the ice cube in a small circle directly on the glass. This will drop the dew point of the area where you are rubbing ice. Some people might even invert a can of air and spray that on the window for 5 seconds.

Try to wipe away the moisture

window with extensive silica staining

Next, try to wipe away the moisture. If you can, there is still life in your window’s spacer bars. BUT! If the moisture remains on the inside pane, your seal has “failed” and you need The Fog Fix! Leave the window for too long and it will look like the above window permanently.

Call us today for a free quote at (587) 997-4646



It’s hard to believe that Snowtember was three years ago today! Let’s be thankful for great weather #Calgary! Winter is coming soon, book your defogging today and enjoy the winter landscape through a warmer window!

You might need new blinds when we are done…

I can see my blinds again

We Fog Fixed this window yesterday. The client looking out her living room says “Now I can pull up my blinds because they aren’t hiding that fog!” She walks outside and looks back in from the deck, “Now I’m going to have to get new blinds!”  Her blinds have existing water damage. It is now fully visible from the deck because it isn’t hidden by the fog!

Transparency in all we do

We saved the window, but transparency goes both ways! We fixed the windows the same day we came out for the quote, without disrupting her day, and perhaps more importantly,with immediate results. Another satisfied client!

Do you think transparency should be one of our company values?

The R Value of Steam

A woman reaches up to open a window.

U-values measure the effectiveness of a material as an insulator in buildings. Solar panels use heat energy from the Sun to provide hot water or to heat buildings. The specific heat capacity of a substance allows us to calculate the amount of energy needed to heat it up.

What does this mean to you, the home owner? Well quite a bit.

U Values.
A dry window has a U value of about .30 maybe lower. Steam has one of the highest U values apart from metal beating out even some molten metals. Steam is very efficient at transferring energy, directly into and out of your house. When your windows are foggy you’re taking on and/or losing more heat than you need to, even with a low-e window!

Your window goes from a U value of .30 to slightly better than a single pane window at 1.22. The R value is < 1.

How do you fix it?

Click here to learn more about how we get the steam and fog out of your window. Start by booking a quote with us today. Simply select the  “Contact Us” on the right hand side of the page. The fog isn’t going to go away on its own! You can also call us any time at (587) 997-4646 or email us at