squeeze an even bead of caulk into and along the gap do this all in one caulking session some people recommend filling the tub 3 4 full with water a good seal around the bathtub that should last for some greater time without leaks mold or mildew general maintenance is required to clean this area press it down tightly so that the new bathtub caulk doesn t migrate under the tape especially at the tile joints if you have them in your shower wall behind the quarter round ceramic pieces was filled with my old caulk job so i had a lot to remove image titled caulk a bathtub step 1 image titled caulk a bathtub step 12 image titled caulk a bathtub step 7 image titled caulk a bathtub step 4 image titled caulk a bathtub step 5 cover with plastic and wait another 1 2 hours don t let it dry out image titled caulk a bathtub step 2 i have ceramic quarter rounds to remove here whereas you ll most likely only have caulk the following photos show the mechanical means of removing the old image titled caulk a bathtub step 6 here s that same area showing mold and mildew beneath the removed tiles and caulk very neat caulking at tub and wall connection image titled caulk a bathtub step 13 image titled caulk a bathtub step 11 image titled caulk a bathtub step 9 then use a putty knife or a drywall tool couldn t find my putty knife to remove the old caulk how to replace caulk in a bathtub or shower using mildewfree image titled caulk a bathtub step 3 image titled caulk a bathtub step 10 mold behind the caulk at the tub and shower wall connection bathtub caulk the natural handyman link above has good information on the type of caulk you should use for your tub and shower wall combination bathtub caulking tape bathtub bathtub sealant tape caulking bathtub painters tape waterproof bathtub kitchen fixture caulk corner seal tape you how to caulk a bathtub images you premium image titled caulk a bathtub step 8 start with a utility knife or razor blade ser at a low angle to cut the caulk seal the low angle is so that you don t cut or scratch the tub when the caulking around a bathtub starts to and become a home for dark stains that signal mould it s time to replace it how to caulk a bathtub you how to caulk a bathtub using foam backer rod to fill a wide before caulking then you ll need to puncture the seal within the caulk with a nail or you may have a pin on your caulk for puncturing the seal prior to putting