When caulking, all you do is fill the crack, right? Wrong! Proper application calls for more. Today, in part one of our series about caulking technique, we learn two sides are better than three. For inside-corner seams and small cracks, a simple straight bead of caulk is fine. For caulk to perform properly with wider gaps that are an eighth-inch or more, the caulk should be applied only to the sides of the gap being filled. If the gap's entirely filled with caulk, it also adheres to the bottom and can fail prematurely as it cures and dries. To prevent this, first push a backer rod into the gap (available at your local hardware store in various sizes). Caulk won't adhere to the backer rod. It will adhere only to the sides, not to the bottom. This makes caulking a gap seam much better. Tomorrow in part two, you'll learn how pros apply caulk smoothly in an episode we call "finger-lickin' good". And that's the On The House tip for today.