How To Seal A Window From The Inside

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If you've been feeling a cool breeze from your windows lately, it's understandable to be concerned. No one likes drafty windows, and who wants a high heating bill? So how can you seal a window from the inside and prevent this? We've checked with window installation experts for their tips.

One of the simplest, most effective ways to seal a window from the inside is by using caulk or sealant. Just fill in the space between the window trim and the wall with a bead of caulk. This fills the gap, sealing it tight to prevent drafts.

Keep reading, and we'll explain the exact steps to seal a window from the inside. We'll give you some other suggestions if the caulk isn't good enough. We'll give you some pointers on what to do if your caulk is cracking and why that happens. Finally, we'll discuss caulk and sealant, which to use, and provide some recommendations.

Young worker sealing joints of home office window, How To Seal A Window From The Inside

How To Seal A Window From The Inside

Attractive young man and handyman insulating his home windows during the winter season

Caulking windows is one of the easiest, cheapest ways to seal your window from the inside. It will eliminate nasty drafts and help you save money on your heating bills. And as a bonus, it is not very hard to do.

Start by locating the leaks to find problem areas that require extra attention. On a cold, windy day, you can check for drafts with an incense stick or feel around the window.

Another option is to use a temperature sensor to find unusually cold spots.

View this temperature sensor on Amazon.

You can then use caulk or sealant to seal cracks around the trim. Work your way around the window, covering the space between the trim and the wall.

You can also use caulk to seal the window's exterior if desired. Place caulk around the entire perimeter of the window.

However, do not put new caulk over old. If the old caulk is no longer in place, first remove it with a putty knife. Otherwise, the old caulk gets in the way of the new, and both will peel off in time.

You may want to seal the entire window during the wintertime to keep your home warm. If you do not plan to use the window for several months, removable caulk can be a quick method for keeping out the chilly winter winds.

If you found any significant gaps or leaks earlier, you can always fill them in with spray foam insulation if they are huge. For smaller spaces, use more caulk in these spots.

For even more savings, cover the entire window with a weatherproofing kit like this one:

See this window kit on Amazon here.

How Do You Caulk A Window?

While caulking is not an especially difficult skill, a few tips and tricks will help you get the best results.

  • If needed, don't be afraid to use painter's tape to keep your seams neat. If your hands tend to be shaky, run a strip of painter's tape about 1/8th inch away from the seam.
  • Do not cut the end of the caulking tube too big. The bigger the cut, the more caulk comes out, and the larger the bead. This can make your finished product look sloppy. Stay as small as you can while still filling the seam.
  • Use both hands on the caulking gun, which gives better control and pressure.
  • Instead of running a continuous bead across the seam, move from one end. Work your way toward the middle.
  • Smooth the seam when you are done, using a wet finger. Start about six inches from the bottom, smoothing out just this tiny section. Continue to move in six-inch areas, smoothing one at a time until done.

Close-up Of Person Hand Applying Silicone Sealant With Silicone Gun On Window

How Often Should You Caulk Windows?

If your home is brand new, you may need to recaulk your windows sooner than you might think. Because of the movement as the house is settling, caulk may peel away from the wall. While this isn't ideal, it is perfectly normal.

As a result, it is worth checking for any big gaps or drafts during the first couple of years. Examine the caulk every six months for two years, making fixes as needed.

However, older homes expect to have to redo caulking roughly every five years. Your exact results can vary based on factors like the quality of the caulk or the weather.

How Do I Fix Cracked Caulk Around Windows?

If your caulk is prone to cracking, even when it isn't very old, the material you are using doesn't have enough flex. Caulk can be very rigid. As a result, it may shrink or crack as windows expand and contract.

Use a sealant in place of caulk. This will give you the movement you need, letting the windows stretch without cracking the sealant.

Old windows in a home suffering from moisture problems.

Another common problem is trying to put sealant in a large gap. Sealant and caulk are best for small gaps, a quarter-inch thick or less. For gaps wider than this, consider an expanding spray foam instead.

Do not try to caulk over old, cracked caulk. Use a putty knife to remove it all and start fresh. Layering caulk may trap moisture. In addition, it can prevent the new layer of caulk from sealing correctly.

Should I Use Caulk Or Sealant For Windows?

While caulk and sealant are used relatively interchangeably, they aren't entirely the same. Both come in cartridges or tubes, which may be part of the reason the names tend to get swapped.

However, true caulk is more rigid than sealant once it dries. For this reason, a sealant is a better choice in areas prone to expansion and contraction. So for your windows, which can experience lots of movement, pick a sealant.

Note that the names can be tricky, and focus on the word "sealant." You may even find it labeled "sealant caulk," as if the terms weren't confusing enough.

What Is The Best Caulk For Interior Windows?

While silicone sealant is a great choice for windows, it may not be the right fit for interior windows. Silicone is impossible to paint. If you try, it will just flake and peel right off.

For most people, skipping the painting isn't an option. Painting over caulk helps it blend in and look clean and neat. Pick a paintable latex, such as this one:

See this caulk on Amazon.

Silicone can still be an appropriate choice for exterior windows or if you won't paint the caulk anyway. It's flexible and durable. It may even last as long as 20 years, saving you from frequent recaulking.

Silicone is also moisture and water repellant, another reason it's a good choice for your windows. Just keep in mind that some silicone sealants are blends containing chemicals that may react with plastics.

If you have any concerns about your window frame, pick a 100% silicone sealant.

This is a popular choice, which is pure silicone. It's flexible, doesn't yellow, and dries quickly.

View this caulk on Amazon.

To Wrap Up

Men's hand uses silicone adhesive with a glue gun to repair worn windows.

Sealing interior windows can help keep your home warm and stop drafts. Using a latex caulk on interior windows is a quick, easy way to fill small gaps and block cold air.

For large gaps greater than a quarter-inch, use expanding foam instead. Consider using a window kit to cover the entire window frame with a clear sheet of plastic film for an even better seal.

If you enjoyed reading this article, try these next:

What's The Best Kind Of Insulation For Interior Walls?

How To Seal Gap Between The Carpet And Wall

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