Sanded and Unsanded Grout? What's the difference?

[Shellback]

I have to repair an area that's tiled above the shower/bathtub. The adhesive/grout that I'm using is pre-mixed and the choices are sanded or unsanded. It's the first time I've worked with this stuff and I don't know what the difference is between the two but suspect it has something to do with the finish of the grout? Thanks. Shellback

*Please REMOVE the obvious for my correct email address*

[Richard J Kinch]

Unsanded grout is white portland cement (plus pigment if colored, possibly polymer fortifiers), which shrinks when curing, and will thus crack in joints wider than about 1/16" or so.

Sanded has fine sand aggregate, which minimizes shrinking. Also slightly rougher texture and a bit different to finish.

The package instructions should instruct you which to use for your application.

[Shellback]

Thanks! Shellback

*Please REMOVE the obvious for my correct email address*