My family's bathroom (bathtub shower) needs to be recaulked, the mold is bad and they've been recaulking incorrectly for years (possible water damage?). There is definitely mold behind the caulk.
Does anyone have any advice on what to do about it?
I wanted to pay a contractor to recaulk and do a minimum or temporary mold treatment, is there anything to look out for so I don't get scammed?
What experience did you have trying to recaulk or fix mold?
Is it expensive?
so, i was imagining doing it myself because i have in this situation. others have good advice in here, so rather than being prescriptive, i'll just say what i did and with what. i probably started by watching a youtube video. if there's a this old house / bob vila one, those are fast and with just the right amount of detail for me.
getting rid of old crap, the most critical part:
i took a utility knife and ran it down the horizontal and vertical planes of the joint to cut out all the old crap. pulled it away and tried to get as much of it removed/thrown away. then i came in with some kind of detergent / soap and scrubby pad, like brillo. something tough, but you don't want to scratch the tub and tile surface so don't use like metal. pumice stone is crazy effective on porcelain. scrubbed away as much detritus and mold as i could. i always use a solution of 15% bleach in water, as this is a recommendation for sanitizing food prep surfaces (total overkill in this situation). most household products with bleach are 5-9%. bleach works best to kill when it has a longer "contact time" and isn't getting chemically bound onto some larger chunk of organic material that should have been wiped away. so when i'm sanitizing an already scrubbed surface, i mist it with my 15% and let it evaporate (open doors/windows) for maybe 15+ minutes. then i come back and depending on how it looks, i give it another soap+water scrub+bleach mist again, or just call it good.
the caulk application thing is fast, but easy to make a mess so i definitely watched a few videos of how people lay beads and what tools they use/prefer, plus their little tricks for slicing open the tip. caulk guns work, though can be fast for first timers. so a practice bead on some cardboard box is a cool move. usually there's a little plastic corner trowel type of thing sold for $1 next to the caulk supplies to run over the bead and push it into the corner/make it look clean. the product you buy will have the cure times listed for how long to let it sit before you run water over it.
EDIT: as far as DIY projects go, this is pretty cheap (~$20 if you have none of the tools/materials) and most of the time between start to "ready to show" is spent letting things dry/cure, so you can take breaks and watch more DIY videos.