The thing is with Spectralock, the sand they use is much finer than the sand in most sanded grouts, and in fact, Laticrete is replacing their 1500 and 1600 series grouts (sanded and unsanded) with a new line called Permacolor-- just like the Spectralock, it has a super fine sand in it, so it can be used in all size grout joints. Now, I tell you all this because the smallest joints I've ever used Spectralock in was with ceramic mosaics-- the steam rooms I did a few years ago, from the steam room book that John Whipple posted the PDF link to a few weeks ago: HOWEVER-- the master bathroom I did down in Andover, Mass. last summer where I did the Carrara wainscot, floor, and shower-- that was all 1/16" grout joint... done with that sanded Permacolor: Bottom line-- although I've never used Spectralock in small joints like that, I wouldn't hesitate to do it.

bill_vincent wrote: "Spectralock's another good choice, but more expense than really necessary." Bill we acknowledge and honor your experience and expertise. In contrast, we have tiled only one large shower and one sink backsplash, both for ourselves, and certainly do not consider ourselves tile experts. But I have seen you make similar responses when epoxy grout has come up in the past, and I find the response very curious. In the total cost of any project where tiling is involved, the cost of the grout materials is usually a very small fraction. Moreover, the DIFFERENTIAL between the cost of cementious grout and epoxy grout to cover a given area is but a fraction of the total materials cost of the grout, so the "epoxy premium" is a small fraction of a small fraction. In our (9 foot by 33 inch small) powder room renovation, the total cost of the Laticrete SpectraLock epoxy grout for the entire backsplash tiling job was $21, while the cost of the tiles themselves exceeded the cost of the grout by a substantial multiple. For the room project in which the materials alone (new sink, faucet, and toilet, plus tile and wallpaper, with new lighting fixtures not certain but under consideration) are running $2,000 to $3,000, the cost of the grout was a drop in the bucket. Because cementious grout is sold only in large bags, the minimum quantity of high quality cementious grout would probably have cost us more than the small Laticrete SpectraLock epoxy grout kit which provided us about 30 to 40 percent more grout than we actually needed. We probably SAVED materials cost by using epoxy grout, in other words. Admittedly, the biggest reason that the epoxy grouting was a DIY project for us was that not one professional tile installer in the Portland, Oregon, area would agree to apply epoxy grout; they all wanted to slapdash cementious grout in there in the shortest time period possible, take their money, and run. By using epoxy grout in the wet environment of a sink, we got grout that we do not need to seal, will never need to re-seal, and which is a very inhospitable host to mold and mildew and just short of impervious to those problems. In the eight years since we retiled our shower using epoxy grout, we have never had a mold problem; the same shower had serious mold issues when the grout lines had been cementious grout. Shouldn't maintenance costs be taken into account when comparing costs between cementious and epoxy grout?

Actually, You'd be better off with the sanded caulk. I said what I said above more for the benefit of others who may go looking for unsanded caulking in the future and read this thread. The same rule oif thumb about when to use sanded and unsanded grout does NOT allpy to caulking. ALthough you CAN use an unsanded caulking if you wish, the whole point to having the two types of caulk is to match the grout as closely as possible, and the sanded caulking, in this case, would do a better job of that. I'd stick with what you have.

I talked to our installer and we will be doing the 100% silicone product in all of the change of plane grout lines. I figure it is better to have it look a little shiny and have the functionality I need. I was just curious how it looked. Do you think we should dig out the grout on the floor butting up to the alcove tub and shower curb? I don't anticipate those being extremely wet areas, but I am not sure if we pay to do that or not.