Advice needed about building a granite floored wetroom in farmhouse, floor is breathable limecrete

[DAX]

Hi,

I am going to build a small (7m2) wet room on the ground floor of a granite farmhouse. The rest of the ground floor is drained breathable limecrete.

In the wetroom at present there is compressed (structural) drainable Foam Glass insulation (Misapor). The insulating slab (lime/Misapor/sand) will go straight onto the geotextile which has the hot/cold water pipes on top (see photo).

There will then be water underfloor heating pipes. Then a 75mm levelling screed, followed by new cut granite flags of approx 400x600 (see photo).
The local quarry can also cut us a solid shower tray (900x1500) in granite to match the flags .

First question:
Is there any way a wetroom can be part of the breathable floor or am i best to separate it and use cement screed/tanking etc?

Second question:
Any tips for the shower tray. Does the granite need to be of a particular quality or grain, does it need to be treated or sealed? What is the ideal thickenss and slope? Will the other granite flags need to be treated?

Third question:
I want the heating pipes to run underneath the shower tray, but as it will be thicker than the flagstones will 50mm screed (with fibres) be sufficient to protect the heating pipes and support the stone shower tray?

Fourth question:
Should I put a layer of insulation board between the slab and the screed underneath the underfloor heating pipes? If so, what would you recommend?

Thanks for any help and advice.

Ross

 

[One Day]

This is quite specialist. Can I suggest you contact Schluter technical (01530 813396) who can steer you on this? Have to admit I would start by talking to them first, before I offered any advice.

 

[Paul Giovanni Raimondi]

I know very little about Schluter, except that they have excellent innovative products, but I would have thought that they are primarily for newbuild? The crossover between old and new technology in buildings is a difficult one. If someone has gone to the expense and trouble to lay limecrete floors I think it will be difficult to find a breathable solution for a wetroom. Surely the two are mutually exclusive?

 

[Ajax123]

I would suggest talking to the Italians about this as this is really popular type of construction over there. Kerakoll have some good products available

 

[Paul Giovanni Raimondi]

Having completely rebuilt a Georgian farmhouse in Ireland, (no cement, primarily fat lime) and now a number of stone buildings in Italy, (no mortar in joints, just what looks like clay), I know that the climate is so different that you have to think about the structure in a completely different way.

 

[Dumbo]

Is your levelling screed lime based .