For the teachers among us, do you remember all the whiny middle schoolers complaining about their math lessons, "Why do we have to learn this? We'll never use it, ever!" Uh huh.*

Yes, the tilers need to come back and grout and seal the tile already in place. Do they really think it should be left unfinished for another month?

For the record, I love middle schoolers, but there is no question they can be whiny.

SInce they measured and are at fault for this mistake they should grout the existing completed tiled wall. If it was my own mistake I would be happy with sealing the tiles for the time being so the grouting could be done a one time when it is all finished. I sealed my marble backsplash before it was installed as per instructions (to make it easier to clean off the grout), that was a pain and could have been a lot easier to do once it was up on the wall. A small roller makes the sealer go on evenly and lightning fast.

I would be more worried about the new tile matching in color what is already installed then about grout and sealing what is installed...

But yes I would for sure have what is there finished up properly

Ajc71 that's my concern as well. He assures me it won't be an issue but I won't feel good until it's here and it matches. I did speak with him and he said someone will come out this week to grout and seal. Thanks for the advice

If the new tile is from a different lot, which it most likely will be since it took so long the first time there could be a night and day difference.

quote - "...the guy who measured did a bad job because we are about 15 tiles short!"
Don't jump to conclusions, there are different ways to layout a tile job which can make a huge difference in the amount of tile needed. Also the installers can make a lot of mistakes cutting tiles or they may not be conscious of the waste yield when making cuts.

Seal the tiles and leave out the grout until the tile is all installed to eliminate grout shade variances from being mixed at different times.

Well now I will be worrying about the tile color until it arrives! I wonder, if there is a problem without the color, is the only solution to take it all out? Or can they remove some of the existing tiles and move them and then intersperse the new tiles in? I imagine it's hard to remove tiles without ruining them.

Those tiles could be so different they couldn't be on opposite walls and look right. I would wait on grouting. Good point on the grout shade coming out different during mixing, too.

Yes, it needs to be done as without sealing the sink may look incomplete.

As I see it, the problem is if you grout the tile that's already up, and the new tile looks terrible so that you want to rip out the whole thing, it'll be much more difficult.

I'd hold off on the grout too. I don't know that tile but if the new stuff isn't an exact match, you might want to pluck out some old ones and distribute the new ones throughout.

Personally, I'd just tape some Saran wrap over the whole thing for protection until it's all ready to seal--fewer days of stink if you do it all at once.

I think that before contemplating tearouts of perfectly new expensive tile you just wait until you get the additional pieces. Encore is a reputable tile company and I am sure they have good quality control over their production and colors. There is a good chance the new tile will match the old tile perfectly.

I would wait to do the grout. imo, that's where you have the most chance of the colors not matching. If you are so inclined, now might be a good time to seal the tiles. Then when the grout is applied it should have no affect on the craquelure of tiles. You can seal the grout later (after it cures) unless you are doing epoxy and then you don't have to seal it at all.

Thanks to everyone for the suggestions and comments. I like the idea I of just putting Saran Wrap up and doing everything at once. Won't look so great for Christmas entertaining but oh well!

It's not as bad as the cookie sheet so many of us have behind our cooktop for months (and months and months...).

Which brings up the point, unless your guests are extremely messy, you can probably just use a cookie sheet behind the cooktop. :)