When seasons shift, the accompanying temperature changes can cause homes to expand, contract, and even crack. If you want to keep your house from letting in cold air, you need to seal all the gaps around your home’s windows, doors, and trim to keep the elements outside where they belong. Here at Today’s Homeowner, we’re dedicated to tackling all the questions you have about home maintenance, repair, and remodeling. In this article, we’ll call on our years of experience to provide a step-by-step guide on how to seal the gaps in your home.

It’s easier than ever to address those cracks and create a seal that will last for years to come. Read on for more tips on sealing the gaps in your house, and while you’re at it, check out our guide on how to insulate windows.

Why Gaps Form Around Windows, Doors, and Trim

Thermal expansion and contraction lead to unsightly gaps around windows, doors, trim, and other joints in a home’s exterior. As temperatures fluctuate, building materials like wood, concrete, and stone expand when heated and contract when cooled. Over time, this natural movement causes cracks and openings to form.

Shifting soil and foundation settlement can also contribute to gaps around the home’s exterior. Left untreated, these openings allow outside air and moisture to enter the house, resulting in the potential for mold and mildew growth inside the walls. Added strain on the HVAC system leads to higher energy bills, and openings can even enable pests to enter and wreak havoc on your home.

Sealing gaps is essential for any homeowner who wants to:

  • Maintain energy efficiency
  • Prevent moisture damage and mold growth
  • Block pests from entering the home
  • Improve curb appeal by eliminating unsightly cracks

Inspecting for gaps and sealing them promptly is part of regular home maintenance. Read on for steps on how to get started on your sealing project today.

Choosing the Right Caulk or Sealant

We recommend acrylic latex caulks as they’re water-based but offer flexibility and durability for exterior use. Since different building materials move and respond differently to temperature changes, using a flexible sealant that can adhere to various surfaces is important.

Acrylic latex caulks are ideal because they remain elastic as building materials expand and contract.

Look for a paintable, waterproof acrylic latex caulk rated for exterior use. The caulk should clearly state on the packaging that it is effective for sealing between dissimilar materials like wood and concrete. Vinyl and aluminum windows are very common, so your caulk should be able to seal these materials.

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An acrylic latex formulation will flex up to 100% of the joint size, preventing any cracks or tears. If you want extra durability, make sure to choose a caulk that offers excellent UV and weather resistance for long-lasting seals.

For larger gaps up to two inches wide, look for a sealant with the highest performance rating. Titebond DuraMaster is our top choice because it:

  • Stretches up to 100% of the joint size
  • Creates waterproof, airtight seals
  • Won’t crack, tear, or pull away from surfaces
  • Is four times more durable than other water-based caulks
  • Comes in more than 13 colors and is paintable after two to four hours

With a lifetime warranty, DuraMaster can permanently seal gaps of any size around windows, doors, trim, and siding.

How To Apply Caulk or Sealant

Sealing gaps around your home’s exterior is a straightforward DIY project. You’ll need a caulking gun, sealant, and basic tools like a putty knife, utility knife, and razor blade. You may also need to consider the types of windows your home has before applying any sealant.

Follow these steps:

  1. Inspect joints and remove old caulk, dirt, and debris with a putty knife or razor, ensuring the area is clean and dry.
  2. Load the caulk tube or sealant sausage into the caulking gun. Snip the tip at a 45-degree angle for optimal flow control.
  3. Slowly apply steady pressure on the trigger to lay down a smooth, consistent bead of sealant. Don’t rush.
  4. Use a putty knife or your finger to smooth it into the sides of the gap.
  5. Allow the recommended dry time based on the sealant’s instructions before exposing it to rain or water pressure.

Repeat this process to seal all problem areas around windows, doors, trim, and siding. Focus on joints prone to movement, like where window frames meet siding or where the door threshold meets concrete. For optimal insulation, you’ll have to seal window frames outside, even with new windows, to prevent any gaps from forming.

Proper sealing can reduce energy bills, prevent moisture issues, and improve curb appeal. 

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Be sure to inspect seals annually and reapply sealant if needed to maintain your home’s protective envelope.

Maintaining Seals Over Time

While high-performance acrylic latex caulks offer longevity, seals may need renewal every few years. However, quality sealants can last for up to 20 years before needing full replacement.

Be sure to check window and door seals at least once a year for signs of deterioration like cracks or gaps. Re-caulk as needed.

Factors like intense sun exposure, heavy rains, and large joint movements can accelerate sealant breakdown. South- or west-facing walls often need resealing more frequently than north- or east-facing walls due to sun exposure.

DIY sealant maintenance may involve:

  • Re-caulking joints every two to four years
  • Choosing quality sealants with 20-plus-year lifetimes
  • Focusing on high-movement joints that fail often
  • Sealing before winter to prevent air leaks
  • Using backer rods for deep gaps before caulking

Regular sealing prevents costly home repairs down the road. If you think you’ve bitten off more than you can chew, consider hiring a professional sealant contractor for large sealing projects or hard-to-reach areas. Look for companies that offer reliable warranties to guarantee their caulk application workmanship.

So, Is Sealing Windows, Doors, and Trim Worth It?

Maintaining your home’s exterior envelope is one of the best investments any homeowner can make. Sealing gaps is extremely affordable compared to the energy savings and averted repairs it provides. Stopping air leaks and moisture entry leads to a more comfortable and energy-efficient home, and it simultaneously limits pest access, prevents mold issues, and boosts curb appeal.

While sealing products have improved a lot in the last few decades, joints still need renewal every few years. Luckily, caulking and sealing exterior gaps is a quick, easy DIY project. With a small time investment, you can make your home weathertight year after year.

FAQs About Sealing Windows, Doors, and Trim

What's the best sealant to use outside?

Use a high-performance acrylic latex caulk for exterior gaps rated for heavy weather exposure. Look for excellent UV resistance and 100% joint movement capability.

How do I remove old caulk around windows?

Cut through the old caulk with a utility knife or razor blade. Then pull up the caulk with a putty knife or scraper tool. Be careful not to damage the surrounding surfaces.

Should I seal windows before winter?

Yes, sealing around windows before winter stops cold air infiltration and reduces heating costs. It also prevents moisture issues like ice dams.

How long does exterior caulk last?

High-quality acrylic latex caulks can last up to 20 years. However, seals may need re-caulking every two to four years, depending on the joint size, movement, and weather exposure.

What's the difference between caulk and sealant?

Caulk and sealant are interchangeable terms. Both refer to flexible patching compounds used to seal joints and gaps.

Further Reading

Editorial Contributors
avatar for Mitchell Layton

Mitchell Layton

Mitchell Layton is a former professional mover who currently lives in Philadelphia, Pennsylvania. Mitchell spent years packing and moving for REAL Rock N Roll Movers, a commercial and residential moving company based in Los Angeles that’s primarily staffed with up-and-coming musicians. That gave him plenty of experience navigating box trucks up and down the winding streets of LA. In addition to moving hundreds of happy customers into new homes and apartments all across Southern California, Mitchell has also performed corporate moves on company lots for Nickelodeon, Warner Bros, Universal Studios, Paramount, and more. After pouring blood, sweat, and tears into his profession, Mitchell has all the helpful tips you need for your next move.

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photo of Lee Ann Merrill

Lee Ann Merrill

Chicago-based Lee Ann Merrill has decades of experience writing and editing across a wide range of technical and scientific subjects. Her love of DIY, gardening, and making led her to the realm of creating and honing quality content for homeowners. When she's not working on her craft, you can find her exploring her city by bike and plotting international adventures.

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