laying terrazo in sand cement base

[astute1]

Hi guys, a question from down under in NZ. I am doing a job which involves laying a terrazzo paver/tile 500x500 x 40 thick onto a concrete base ( internal). Was intending to use modern modified cement base adhesive. However the construction team have set all of the joinery for a 50 mm paver and they require the paver to run about two mm under the level of the joinery. So with the normal addy, I'm going to be about 6-7 mm too low to hit the required height. The area to cover is about 300 m2 so the SLC option is way to expensive. So knowing I cant get the required height out of the addy Im thinking of laying in sand cement. I know I will get the lift out of this. Am I digging myself a hole here. Or is this a genuine solution. The pavers/tiles are created by having the bottem 20 mm plain concrete and the top 20 mm in the terrazzo. They:hurray: are not moisture sensitive. Having read other posts it seems that if I slurry the concrete and use addy to back butter the paver/tile It should stay there. The residence is around the $3-$4 million mark so I have to get this right. Your thoughts are appreciated. :hurray:

 

[AliGage]

Hi and welcome.

Don't know what brands of addy you can get over your way, but what about a PTB?

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[Ajax123]

Thick bed addy. Minimum depth for sand cement under terrazzo is usually 35mm but if its modified with SBR you can go thinner. Or you could negotiate a different datum.

 

[Alan.P]

Pourable thick bed adhesive ( PTB ) with that weight will probably push out from under the tile could you overboard the slab ? depending on costs down under ??

 

[astute1]

Pourable thick bed adhesive ( PTB ) with that weight will probably push out from under the tile could you overboard the slab ? depending on costs down under ??

Thanks for your feed back, we are considering overboarding the slab as suggested. renegotiating the datum is not an option. Getting that 8mm extra height is always and issue. regards

 

[Diamond Pool Finishers]

You should never lay screed under 25mm thick, but if you wet-down the concrete then slurry coat it with neat cement & SBR mixed to pourable mix then lay the sand and cement screed with SBR/water ,lay this screed into the wet slurry !,if the slurry drys-out it's not good,wet it again, then back butter the tiles with thin -set then bat them into the damp screed ,and bob's your uncle , hope this helps you cobber.....lol