Can you re-grout over sealed grout?

[Mike/Mass]

The grout in the shower is semi fresh (months old) and has been sealed. I noticed some low spots and a couple of pinholes that I'd like to fix with the same grout that was used. Can I re-grout over the sealed stuff or do I have to somehow strip the sealer off with a solvent? Also have one spot in the niche that is a little yellowish... I'm thinking its contaminated with something. Will bleach whiten it up after I strip it?

TIA-Mike

 

[Doghouse Riley]

With the grout in our shower, I always try a mould removal spray first and then see what really needs doing. I use the blade of a small screwdriver to remove any that won't shift with the spray. Then give it another spray. Leave it to dry then fill with new grout. It needs to "key in" to the old grout.

 

[Mike/Mass]

OK thanks for the tip. Generic mold remover from HD/Lowes?

 

[Doghouse Riley]

OK thanks for the tip. Generic mold remover from HD/Lowes?

There's a lot of them on the market, as I said it's a case of spraying the tiles then leaving it for 24 hours.
While you're at it check the silicone between the shower tray and the wall. Whilst I was doing a bit of regrouting I noticed ours was getting a bit discoloured in places only a few years after it was fitted, so I scraped it all out and did it again.

 

[Mike/Mass]

There's a lot of them on the market, as I said it's a case of spraying the tiles then leaving it for 24 hours.
While you're at it check the silicone between the shower tray and the wall. Whilst I was doing a bit of regrouting I noticed ours was getting a bit discoloured in places only a few years after it was fitted, so I scraped it all out and did it again.

As of yet, this new grout hasn't been sealed, so its very fresh, about a month old. Bathroom was completely redone this summer. All the silicon corners are fine, the only weird spot is in the niche, and one 1/16" pinhole outside the shower on the floor (same new white grout).

 

[Doghouse Riley]

As of yet, this new grout hasn't been sealed, so its very fresh, about a month old. Bathroom was completely redone this summer. All the silicon corners are fine, the only weird spot is in the niche, and one 1/16" pinhole outside the shower on the floor (same new white grout).

You say this was only done a month ago?
If you didn't do it I'd get the contractor back in to fix it.

 

[Mike/Mass]

The contractor who did it was the contractor I don't want to call again. I won't get into it LOL... I'd rather deal with myself. They were excellent remodelers, carpenters, and everything else, but the carpenter who also did the tile work... should stick to carpentry and forget tiling. Next bathroom I'm using a tile guy I know who's done work for me and my family before.