Pebble Shower - Grout Selection

[traderfjp]

Hi,

I've installed a flat pebble shower floor over a Schluter foam pan. It looks nice. I need help with grout selection since these flat rocks don't drain as well as some flat tiles. It seems that Mapei Ultra Pro FA grout can handle joints up to 3/4". There are many grouts that can't and I have read of lots of failures. The other grout is either a Spectroloc 1 or Spectraloc pro. The pro is an epoxy grout. The 1 is similar in attributes but is not epoxy. I've read not to use epoxy because if water does find its way under the tile it can't escape. I've read that epoxy is the best product for my application. Then I have read that the Ultra Pro is the proper product and have read that it should be sealed even though its self sealing and I have also read that if used don't seal anything. I'm a little confused and could use some help and advice. Thanks

 

[Wesley]

Hi, I have recently done the same - limestone, flattened pebbles, over a schluter foam pan, with linear drain.
I used a white Ardex adhesive, 12mm (almost half inch !), to bed in sheets of pebbles and ensured all pebbles were fully embedded in adhesive.
I was concerned about the size of some of the spaces between pebbles. After speaking to Ardex, I chose to use their new epoxy grout (EG 18 plus), which is recommended for wet rooms and pools, with spaces up to 13mm (half inch).
So, after installing pebbles, I cleaned and applied 2 coats of sealer over all, grouted and cleaned, followed by another 2 coats of sealer the following day.
Bathroom is still being refurb’d, but so far shower (in use) is all good.
I’d suggest : talk to Mapei technical (or whichever brand you choose to use), be guided by their suggestion / recommendations. I’m a fan / user of Ardex - great local support.