How to Caulk a Window Pane? (Step-By-Step Tutorial)

Caulking is one of the best ways to seal gaps in windows. It is easy to apply, prevents the ingress of moisture and insects, and is also non-toxic. The sealing off of air leaks also increases the energy efficiency of your home, thereby letting you save money on utility bills.

These aren’t the only reasons why learning how to caulk a window pane is a really smart move. Most people who do caulking are aware that it’s a ‘once and done’ type of job. It needs to be redone only when the original caulking has worn out or dried off.

How to Caulk a Window Pane

Follow these steps to caulk your windowpane:

Step 1: Inspect your home

How many windows do you intend to caulk? Are the windows damaged and, if so, will the damage prevent the caulk from achieving a good seal? How much time will each window need? For reasons that we will describe in the following steps, timing is crucial. You must have a fair picture of the length of time the entire project is going to take.

Step 2: Identify the type of caulk you need

Most people pick up the first caulk they see on the shelves. That’s a wrong approach. Depending on the type of your caulk, it might be fit or unfit for your situation. Here’s how:

  • Acrylic latex caulk

One of the defining attributes of this caulk is its ability to remain oblivious of temperature changes. Regardless of whether it’s hot or cold out there, acrylic latex caulk won’t flex or expand. As a result, this caulk is unsuitable for moist environments and window frames.

  • Siliconized latex caulk

These caulks have excellent moisture-resistance and can be used in almost all weather conditions. Their adhesive properties dwarf those of acrylics and they also come handy as sealants.  You can use them on both wooden and metal window frames.

  • Silicon latex caulk

In contrast to what most people believe, silicon latex caulk is different from Siliconized latex caulk. It is more durable and has better water resistance than its counterpart. However, it performs poorly on wood and has meager rust-resistance.

  • Polyurethane caulk

Regarded as one of the best outdoor sealants, polyurethane caulk can be used on glass, wood, and metal. But if you’re going to use it in outdoors, you’d have to paint over it as it isn’t UV-resistant. This caulk is also pretty expensive, a factor you must consider if you’ve multiple windows to caulk.

Step 3: Gather the necessary supplies

Gather the necessary supplies

You’re going to need the following items:

  • Caulk and caulk gun
  • Putty knife
  • Razor blade
  • Rag

Step 4: Remove old caulk from the windowpane

Remove old caulk from the windowpane

Select a window on the ground floor or one that is easy to access. Remove any old caulk that you may previously have applied around the frame. Use a putty knife to remove the largest pieces and then you can use a utility knife to eliminate the remaining bits.

Step 5: Prepare the window’s surface

Prepare the window’s surface

Inspect the area around the window frame and the frame itself for any damage. Repair any wood that may have rotten and remove any old paint on the frame that might prevent adhesion. Wash the entire frame but make sure that it is dry before moving on to the next step.

Step 6: Place the caulk tube in the caulk gun

Place the caulk tube in the caulk gun

Remove the cover on the inlet of caulk gun. Place the tube inside and then screw the cover back. Make sure that the tip of the tube is in the yoke. Slightly squeeze the handle to attach the plunger cap against the tube’s end inside the rod.

Step 7: Cut the tip of the caulk tube

Cut the tip of the caulk tube

Use a utility knife to cut the tip of the tube at a 45-degree angle. The width of the gap that you’re trying to seal should decide the size of the opening that you cut on the tip of the tube.

Step 8: Apply the caulk to the window

Apply the caulk to the window

Press the tip you’ve just cut against one corner of the window, and start applying caulk. As you’re moving the gun towards the other corner, make sure that you’re applying the caulk in a continuous bead. Once you’ve reached the end point, stop the caulk’s flow by pressing the release mechanism.

Step 9: Use a rag to remove excess caulk

Use a rag to remove excess caulk

Also known as ‘tooling,’ this process requires you to remove excess caulk and smooth over the remainder. Wrap a rag around your finger and then roll the covered finger over the excess caulk to remove it.

Final Step: Give the caulk enough time to dry

Depending on the weather out there, the caulk may take as little as 12 hours or as much as a whole day to dry. Regardless of the time it may take, the caulk should be left alone during this period. Only then will your project be successful.

What are the Dos and Don’ts of caulking a windowpane?


  • Do use a caulking gun with a thumb-release mechanism
  • Do use both your hands to control the caulking gun
  • Do tooling to smooth out the caulk after you’ve applied it
  • Do remove the old caulk before applying the new one


  • Don’t caulk when the temperature is less than 45*F (7*C)
  • Don’t cut off too much of the caulk tube’s tip
  • Don’t apply too little caulk or it won’t hold onto the pane
  • Don’t apply too much caulk as it will ruin the trim’s contour


Whether your closed window is letting in air drafts, the increase in your home’s energy consumption is showing in your utility bills, or moisture and insects are making their way inside your room through the peeps in the window, caulking the window pane is the ultimate solution to all these problems.

However, as you have seen by now, the process of caulking isn’t straightforward. From the first step to the last, there are many pitfalls where things could go wrong. Provided you’re stuck in a step and don’t know how to move forward, feel free to get in touch.

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