Sealing tile grout necessary?

[Darro]

Hi,

Do I need to seal unsanded grout around ceramic tiles on a shower stall wall that gets no direct water spray?

Background: I must tile over the opening that was made in the existing tile wall in order to install a new shower valve. I'm quite sure the existing wall has unsealed grout and there hasn't been any apparent seepage into the drywall backer board since it was installed 25 years ago. I'm also able to clean all grout lines between the rest of the existing tiles from time to time without much effort. Someone I know has warned me that sealing the tiles may lead to patchy grout discolouration as some of the sealant wears off in places over time.

It sure would be good to know whether the tiles should be sealed and if so, why.

Thanks in advance for your replies, Darro

[dadiOH]

Yes. There is no reason not to...it is easy, cheap and good for mental health. ______________

You took off the tile and looked? ________________

So seal them again. Nothing lasts forever. _________________

The tiles are already sealed, assuming they are glazed. Since they are afixed to drywall, I would absolutely seal the grout. Silicone sealer is good. _______________

To keep the grout from sucking up moisture - spray isn't necessary, condensation gets sucked too - wicking it back to the drywall, destroying the drywall, growing mold, rotting the framing. Like that.