How ? Cement based TERRAZZO on a calcium sulphate screed.......

[The Legend; Phil Hobson RIP]

Hi Fergal, and:welcome: I presume by your term,( insitu terrazzo) you mean mixed on site and laid insitu, as in on site, not preformed terrazzo tile? Being rolled, and then polished? as in the old way

 

[fergal]

My description of in situ Terrazzo is as you say AJAX123, the pressed wet bed method, only this time it's not a fresh sand and cement screed.The client wants the faster heat responce time of the Gyvlon thats why he went for under floor heating. But the clients wife wants a Terrazzo floor and she has been told that the cement based Terrazzo is the best on the market.

I would like to know is this possible on a gyvlon screed and if anyone has done it before and are able to give me a few pointers.

On a few occasions before we have done a heated Gyvlon screed,primer it and then placed a sand and cement screed on top fixing the stone tile's direct on to the fresh screed.Would this be something like the process of putting down an insitu Terrazzo as i have never actually seen one being done?

 

[Ajax123]

My description of in situ Terrazzo is as you say AJAX123, the pressed wet bed method, only this time it's not a fresh sand and cement screed.The client wants the faster heat responce time of the Gyvlon thats why he went for under floor heating. But the clients wife wants a Terrazzo floor and she has been told that the cement based Terrazzo is the best on the market.

I would like to know is this possible on a gyvlon screed and if anyone has done it before and are able to give me a few pointers.

On a few occasions before we have done a heated Gyvlon screed,primer it and then placed a sand and cement screed on top fixing the stone tile's direct on to the fresh screed.Would this be something like the process of putting down an insitu Terrazzo as i have never actually seen one being done?

You could overlay the Gyvlon screed with a sand cement screed and press the terrazzo into this yes. I have seen this done with various tle types over Gyvlon. Typically the sand cement bed would be around 45 to 50mm deep so it would actually increase the depth of the floor which would have an inevitable effect on the mass of the floor thus affecting the response times for the underfloor heating system. The underfloor heating should still have been comissioned prior to overlaying and then I would coat the screed with a couple of coats of Acrylic Primer. There may be some chemical reaction at the interface between the two screeds but as the sand cement would be pretty deep I don't see this as a major issue. The alternative would be to use water dispersible epoxy primer which would completely remove any chemical reaction risks.

Clearly you would not be able to press the tiles into the Gyvlon screed but I guess that is stating the obvious (at last I hope so - LOL) Are there no other tiles on the market which mimic Terrazzo which you could install with a standard adhesive......

Thinking about it though is there a pourable thick bed adhesive that you could use....not sure but perhaps the pro tilers on here might be able to say.
Also you seem to be saying that you have not done the wet bed method - is this something you should be taking on if that is the case or have I misunderstood your last comment.