You answered your own question: "I found out that the subcontractor used a thinset adapted to small tiles up to 15"x15", and our tiles are large 24"x48".

Don't worry about 'code'. Go to the GC with the subs mistake. Show him/her the bag used that CLEARLY states 15" x 15" and then show the GC your PURCHASE order of tiles that are 24"x48". Tell the GC you want the tile install corrected. You can also explain the spot welding was used on very heavy, (probably very expensive) tiles.

Then show the GC the tile manufacture's 'installation instructions'. If you have to find it, down load it and print it (3 copies = 1 for you + 1 for GC + 1 for sub). Date it and sign each copy to show the date you handed it over.

By DOCUMENTING this event, the GC will recognise (ahem....really SHOULD recognise) the seriousness of this matter. The GC is the go-between for you and his subs. If the GC has never worked with this sub before (or at least not for a large tile install) then it is up to the GC to find these things out about who s/he hires. They won't know the *cost of using someone who is subpar (yes...the sub has done an oopsa that is not on the 'Industry Standards' list) until you MAKE the GC understand you want it redone. That's when EVERYONE learns.

First things first, send and email to the GC letting him/her know you have found an anomaly with the thinset the sub used for the tiles. Ask for a meeting as to how to move forward with the issues you have found. You hand over your evidence (warranty, installation requirements for the ceramic) to the GC that state the install was most likely WRONG.

Give the GC the chance to stand up and make this right. Any issues with subpar work done by the subcontractors is at the COST of the GC. This is his/her circus because s/he is using his/her monkeys.

IT is 100% not industry standard to spot set, California only permits and requires hot mop and pan inspections they could care less about spot bonding standards.

You need a written contract that referances Tile industry standards to further protect yourself.

What does your detailed Scope say in the tile sectiin of your contract?

Showers need 95% coverage behind the tiles- spot bonding is absolutely not acceptable.

Thank you all for the helpful information. I asked about code because once I realized that, I froze the project for now, and the subcontractor immediately threatened that he will put a lien and go to the county ask for an inspector to visit us.

If the work was not done to code, I believe the GC is responsible (I don't know if the sub is licensed). That's why I want to know whether a city inspector will require to have everything redone, will they remove some tiles to look behind (which is equivalent to having it redone), and is it possible that it is considered okay and that I would have to pay for redoing it in a safe way?

again, does your contract state tile install will meet TCNA, ANSI, and all product mfg install specifications?

No it's a simple item list with estimated timeline, not a detailed scope contract. Isn't following code implied when hiring a licensed contractor? I'd like to know what do I risk and what do they risk if a city inspector is sent to the site.

And of course also whether you think this job can last long and not cause problems, or is it likely to break or even be a health threat to us on the medium and long term.

@Pnch ..."I'd like to know what do I risk and what do they risk if a city inspector is sent to the site."

Go ahead and find out. When the inspectors show up, go ahead and pull a few tiles off the wall to SHOW the spot welding....and then complain to them about the spot welding. A 'wink-wink' nudge nudge can always get you what you want. Remember: YOU are the customer who ASSUMES the LICENSED PROFESSIONAL you hired will build "To Code". It is part and parcel to a renovation that uses the services of a licensed pro.

Awesome Dragonfly! I would definitely print off that little gem and take it with you when you speak with the GC.

Don’t be under the illusion that a code inspector knows tile standards, or cares about them. They don’t inspect tile. They inspect rough plumbing, if a plumbing permit was pulled. That may or may not include a flood test.

Most places, don’t do flood tests. They don’t have the time. That doesn’t mean that a contractor shouldn’t do one. Just that you’re not getting an inspector out to view things that aren’t required to be viewed. They have their hands full inspecting the drainage for the new subdivision that backs up the sewage in the neighborhood next door.

No amount of after the fact second guessing makes up for the lack of hiring the qualified person on the front end, and having a detailed contract with that person. Without the right contractor, even a detailed contract is worthless. other than it protects you from a lien for firing for cause.

Basically the building inspector will say, yep all the tile is on the wall. Unfortunately they do not give two craps about whether it is to industry standards or not.

It sounds like you are doing the bathroom remodel without a permit and now that you called out your GC on his work practices, he threatened to call the inspector on you, not to look at his work, but to get you cited for no permit? Or did I misread the post?

I have no issues with choosing not to go the permit route for a basic remodel, specially in CA where they mostly care about collecting fees, but you have to trust that your GC will do the work correctly when no one is watching over their shoulder.