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Posted: Thu Nov 07, 2013 1:32 pm
by PavingSuperstore
We're quoting on a job to lay a glass pebble mosaic at a preschool and could do with a second opinion on the type of adhesive to use for the pebbles. A standard mortar is not going to be sticky enough to keep the stones in place and a GftK type mortar will be too grainy I think. We cannot have any risk of the pebbles working loose with the young kiddies around. I'm thinking that some sort of exterior tile adhesive would be the best option. Any ideas?
Posted: Thu Nov 07, 2013 2:08 pm
by higgness
Check out Ardex
http://www.ardex.co.uk/Store/tabid/96/CatID/9/Tiling_Adhesives.aspx
look at the stone cladding adhesives.
I have some pebble mosaic on a net laid, badly, lose a few piece every year or so.
Posted: Sun Nov 10, 2013 9:12 am
by Tony McC
Or simple SBR-beefed-up mortar with a bond bridge. This is what I've used for pebble mosaics in a previous life.
God, they're hard work! Every time I did one, and there weren't that many, I thought to meself: next time, double the price!
Posted: Mon Nov 11, 2013 10:58 am
by PavingSuperstore
The glass pebbles are around 14-20mm diameter and being glass, are smooth and shiny. I'm thinking the particle size of the mortar needs to be as fine as possible to ensure good all round adhesion. We cannot have any risk of the kiddies picking the pebbles out and eating them. Also, as the glass pebbles are translucent, the mortar probably needs to be white. I'll bear in mind the labour costs - can imagine this will be a bit of a job.
Posted: Mon Nov 11, 2013 6:55 pm
by cookiewales
PavingSuperstore wrote:The glass pebbles are around 14-20mm diameter and being glass, are smooth and shiny. I'm thinking the particle size of the mortar needs to be as fine as possible to ensure good all round adhesion. We cannot have any risk of the kiddies picking the pebbles out and eating them. Also, as the glass pebbles are translucent, the mortar probably needs to be white. I'll bear in mind the labour costs - can imagine this will be a bit of a job.
Bathroom stores have them on sheets once stuck down they take some shifting silica sand white cement sbr job done 
Posted: Tue Nov 12, 2013 10:26 am
by Tony McC
If it has to be a white matrix, then a tile adhesive (outdoor grade, obv!) is the easiest option.
I was watching a demo of just what is possible using Elite Crete Systems trowel-down cementitious overlay a couple of weeks ago. That is almost pure white but can be tinted to suit any purpose. It *does* need to be laid over a concrete substrate, but I think it might well do the job
Posted: Tue Nov 12, 2013 10:55 am
by PavingSuperstore
Thanks for the info. These are the pebbles we're using 
We're creating 'the sea' with different waves of colour from dark blue through to light blue, turquoise and white where it meets the sea shore (sandpit).
I'll look into the recommended base options to see which will be the most suitable.
Posted: Wed Nov 13, 2013 10:57 am
by higgness
These look like what we call glass gems.
I just wonder if one of these broke/got chipped, they would be very shape and dangerous.
Having seen and pick up broken ones around the yard, the edges are lethal. Just a thought
Posted: Wed Nov 13, 2013 11:43 am
by PavingSuperstore
It's a valid point. We'll put it forward in the risk assessment. I'm guessing it won't be signed off if the risk is too high and we'll have to come up with a new plan for the sea!