How to choose the right type of caulk As you examine your home, check the caulking on the inside and the outside of the window. The location determines what type of caulk you’ll need.

The glass block window panel sits on the block or concrete wall and is held in place with mortar and caulk. When it comes to basement windows, there’s nothing more practical than glass block ...

If your window has gaps larger than 1/2 inch, caulk may not work well. If these gaps are deep, expanding foam insulation designed for window and door use may be necessary to fill the cavity.

Just be careful. You want to use real, 100-per-cent silicone caulking, not one of the new “siliconized” caulkings that are out there. They won’t work nearly as well in this application.

Look out for gaps where caulking or sealant has pulled away from the window frame. Solutions for Fixing Drafty Windows Caulking It's fairly simple to re-caulk a drafty window.