We moved in our house about a year ago. We had a water leak stain show up in my kitchen ceiling right under the master bathroom shower. I was able to pinpoint the leak to a bad caulk job where the shower pan meets the door threshold. The caulk was covering a pretty large gap between the two pieces. See picture below. Any thoughts on how I should fill this in? Spray foam and then recaulk?
Clean very well, then wipe with alcohol. Plug gap with backer rod thicker than the gap, then caulk. Pure silicone caulk will stand up the best in the shower. Read caulk tube instructions twice. I recommend you practice smoothing the silicone caulk in a corner between 2 scrap boards as is is very sticky. Do not cut the caulk tube too much because you are much better off applying too little and adding more vs. applying too much and trying to get all the excess off. Good luck. Backer rod from Home Depot, Lowe’s, etc.