Grout not getting hard on a regrout... Tried 3 times. Two different batches.

[CanOfWorms]

OK. So my grout was shabby. So I scraped as much of it up and regrouted.
It didn't harden it dried, but did not get rock hard. You could scrape it up with a toothpick.
So I scraped it up again and followed the directions to the letter.... again.
Again the same thing. It was still water soluble.
So I bought some better grout from the tile place and tried again. It didn't get hard.

The area is dry and room temp is about 65-72 degrees F.

In some places the grout is removed all the way to the subfloor and in other places it is little deeper than 1/8"
IN both places it is still soft.

Since taking it up is cake I want to try straight Portland cement. Is this crazy? Of course it is crazy, but will it work?

If I do straight Portland how soon should I damp sponge?

 

[Jadnashua]

Is this some grout you have saved? Once a bag/box, whatever, is opened, moisture can hydrate the cement, and while it may look good after you mix it up, it is essentially more like grains of sand, as the cement is already cured. Depending on how an open container is stored, it might go off in a very short time.

So, try some fresh stuff. You need some depth for the new grout to get a good bond and have any strength. FWIW, cement based products achieve their rated strength after 28-days, but they achieve a fair amount of that after 24-hours...but, it can still be pretty soft for awhile.

 

[Sponsor]

 

[hj]

Use an epoxy based grout, such as Kerapoxy.

 

[CanOfWorms]

I will try Kerapoxy.
First box used immediately. Retried with same stuff 5 months later. That set for 3 weeks before use. I bought a new box of good stuff from a tile place. That was laid down and not touched for about 5 days before dry wiped and it all came up like grains of sand.
Its not that it isn't even bonding, it is not 'activating' Were it stting and not bonding it would come off in hard strips.
I guess it is possible I got two bad batches.