I have a lovely slate floor in my hall and dining room, but the old (probably 35 years) grout is cracked and some of the slates have come up.
I want to eradicate ALL the old, yucky grout, replace the missing tiles, and regrout the whole shebang with grey or black grout. Of course this probably sounds a lot easier than it is.
I’m willing to chip the old stuff out by hand if necessary. Can I then just regrout per the directions on the grout container? And does anyone have any grout recommendations? The salesman at Lowe’s (doing one of those “now, li’l lady” things) sold me some that I now realize is “not intended for use with slate or other porous materials”.
This doesn’t, btw, have to be a last-forever floor. Six months to a year will be fine; then we will probably replace the thing anyway.
Any advice happily accepted.
~karol
A short-term fix is, I believe, not the correct solution.
Regrouting a slate floor is no small task for a handyman/handywoman. If you only want it to last six-to-twelve months before replacing the floor, then I’d suggest that you don’t do the regrout job at all. I’d fix the loose slates for safety reasons, though.
Id take some close pictures of the floor & take them to Home Depot or a similar store & ask the guys what to put on it. There are new products all the time so you never know what they might have. If they have cement patch crap, must be something for grout.
I agree with GrizzRich–don’t do a half-assed job now when you can do a whole-ass one later. 
If some of the slate pieces are coming up, you may have some problems with the sub-flooring. Spot-patching will look awful, and will crack right away if the floor is not stable.
If a home-improvement job is worth doing, it’s worth doing right. Trust me…
FYI, though, if you do need to just replace the grout, Dremel makes an attachment for their rotary tool that will remove grout. I’ve used it, and it is definitely a time-saver.