How to Choose Caulking for Sealing Cracks on Your Home

Sealing up cracks and gaps on the outside of your home, such as around windows and doors and where siding meets trim, can significantly reduce the heating and cooling costs for you home.

Keep these tips in mind when caulking cracks on your home:

  • Choose a mildew resistant, exterior caulking.
  • Select a paintable caulking if you plan to paint over it.
  • Use a utility knife to cut the caulking tube at a 45° angle.
  • Keep the size of the hole in the caulking tube small.
  • Use a can of expandable foam to fill large cracks.

Watch this video to find out more.

Further Information


Danny Lipford: Don’t underestimate what a significant impact you can make by simply sealing up all of the gaps and cracks.

Allen Lyle: You know, if you were to take all of those gaps and cracks and combine them, on the average house, you’d have a hole about one square yard. Yeah, three feet by three feet. That’s why it pays to seek out and seal those cracks. But easier said than done, right? Have you been down the caulking aisle lately? Options are confusing, so let’s look at just a few of them.

A lot of people go straight for that 100% silicone. Great idea. If you apply it correctly, practically guarantees a waterproof seal. Here’s the drawback, look over here. When you look at a crack like this, silicone is clear. You put it on, you’ll still see the crack. You cannot paint this, silicone will not accept paint.

So, you may want to go with a siliconized latex. Either one is great. When you’re talking about outside make sure it says “exterior” on it. Or in this case, you’ve got flashing, windows, doors. That tells you this is for the outside.

When you are using it, a 45-degree cut on the tip. I don’t like to go down any further than a quarter of an inch. Gives you more control over it. One other thing, when you’re looking at the caulk, look for something that has something in it for mildew.

Also, you might want to think about picking up a can of this, because not all of those cracks are going to be sealed with caulk. Expandable foam is great for filling in those larger voids that caulk simply can’t seal. So, seal it up. Save that energy.


  1. Danny, We replaced some older windows with new windows. We have some large cracks that are too large for caulk. What do you recommend for sealing up these cracks. I found some expanding foam that states it’s for windows and won’t bow out the new windows. Is that the best? Thank you

  2. How to seal and what to use , on brick fireplaces with air drafts inside around fireplace, between cracks that let in alot of cold air.

  3. Can your phone be you around air conditioning vent lines on the outside or came from used on the outside of the house code to the Partman says it cannot be

  4. we have a hole big enough for a chipmunk to get into right by the bottom of the flap on the garage door. Not sure what to use because there is brick there.

  5. Hi,
    I see cracks around all the second floor window trims where the trim meets the stucco. How do i fix this? What products should I use? NOt sure how to attach pictures.


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