I have a small gap (2mm) under the window sill that is causing some draft to come inside the house. I have attempted to correct this using the Ge Silicone Caulk, but the draft continues to come in.

So I am going to now try the gap and crack sealant in that area? The name of the product is Gaps and Cracks Insulating Foam Sealant and it is available at home depot.

How can I stop the draft from coming in? Is this the right product that I should use?

The temperature outside is 20 degrees F.

3 Answers 3


If you caulked it and there's still a leak, you didn't caulk the whole gap. Air isn't going to come through silicone caulk. For such a small gap, expanding foam is overkill and may do more harm than good if it expands too much and widens the gap, which could cause the window to start sticking.

Another possibility is that there are additional gaps and holes in the area. Windows--especially old ones--are notorious sources of air leaks. Caulk the heck out of every gap you can find. If the windows have wood trim, caulk that to the drywall and the windows using color-matched or clear caulk. If you really want to do a thorough job, you can temporarily remove the trim and seal the exposed area between the rough opening and the window with expanding foam--be sure to get the kind that Tester101 recommended for this--the low-expansion window & door foam--and then replace the trim. And if your windows are of the very old variety that have poor seals, add stick-on compressible foam gaskets to the sliding sashes that contact the frame. You'd be surprised how much that can help.

  • Removing the trim does not lie within my current set of skills. Also it is freezing cold outside the window. I have caulked the heck out of it, but there are still some gaps. Also this window is a casement window.
    – abhi
    Feb 2, 2015 at 14:59

If the product your talking about is GreatStuff (which it sounds like it is), you'll want to use the window and door variety instead.

The gap and crack formula expands too much, whereas the window and door stuff doesn't expand as much.

  • Yes it is great stuff.
    – abhi
    Feb 1, 2015 at 4:52

How old is this window?

In the past, I have had air come in from between the panes and around the window tracks on older (~1900's) homes.

Do you hear the window move when the draft is felt? If so, you have to seal around the window on the inside.

There are tons of methods which range from temporary to permanent. Keep in mind that caulking the window shut may complicate your egress in the event of a fire.

Many older windows are painted shut, so that may be a non-issue.

To stop the draft until you are able to locate it, you may want to hang an old comforter, buy heavy curtains (some are insulated) or place some other type of temporary thermal barrier over the window.

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