Almost every large water damage job we repair started as a $6 tube of caulk that nobody replaced. Sealant is a wear item. It has a service life of roughly five to ten years indoors and less than that on a sun-facing exterior wall in Los Angeles. When it fails, water goes into the wall or the subfloor and stays there.
There are dozens of sealants and they are not interchangeable. A shower change-of-plane joint needs a 100 percent silicone rated for continuous wet exposure. An interior trim gap needs a paintable acrylic latex. An exterior stucco-to-window joint needs a urethane or high-performance elastomeric that stays flexible through thermal cycling. A natural stone counter needs a neutral-cure silicone that will not stain the stone. Using the wrong one is why so much caulk fails within a year - and why it is usually the mildewed, cracked, peeling kind.
Ninety percent of this job is removal and preparation. Old sealant has to come out completely, the joint has to be scraped, solvent-cleaned and dried, and mould has to be killed rather than sealed over. Caulking on top of old caulk looks acceptable for about three months. We strip to substrate every time.
Cracked, missing or crumbling grout is the other half of this work. We remove the failed grout, clean the joints, regrout with the correct sanded or unsanded product, and seal it. We also correct the classic error of grouting a corner joint that should have been caulked - corners and changes of plane move, and grout in a moving joint always cracks.
This is the single highest-return maintenance item in a house, and it is why we offer it as a standalone service instead of burying it in a bigger job.
Every five to seven years as routine maintenance, and immediately if you see any gap, crack, dark staining or peeling. If you can push on the joint and it moves independently of the tile, water is already getting behind it.
No, and anyone who does is wasting your money. New sealant will not bond properly to cured old sealant, so it peels within months, and any mould underneath keeps growing. Full removal is the job.
Because it is grout in a joint that needs to flex. Wall-to-wall and wall-to-floor corners move slightly with the building and with temperature. Industry standard is a flexible sealant in those joints, not grout. We cut it out and do it correctly.
Yes, in most cases. If the mould is in and on the sealant, removal and resealing solves it. If the mould is behind the tile because water has been entering for a long time, the substrate may be compromised - we will tell you honestly which situation you are in after we open the joint.
If you have one tub joint, careful DIY is reasonable. If you have multiple wet areas, natural stone, or you have already tried once and it failed, the material selection and prep are where it goes wrong. A half-day visit typically covers every wet joint in an average home.
