Hearth for Narvi 20 with low firebox

[Mickfromaus]

I’ve just built a solid timber floored sauna and have purchased a free standing Narvi 20 wood burning heater for it. The firebox is only a mere 25mm (1”) off the floor (no inbuilt stand that raises the firebox). Struggling to find any info on thickness and materials for building the hearth. My presumption is given the lack of distance between firebox and timber floor, it’ll need to be quite thick.

Looking for suggestions.

 

[begreen]

The floor needs protection but unfortunately the manual does not provide a specification. They seem to be suggesting to get a Narvi base. Would cement blocks be too rough?

FLOOR MADE OF COMBUSTIBLE MATERIAL OR A TILED FLOOR, UNDERFLOOR HEATING
As the heater has a double bottom, thermal radiation reaching the floor is less than normal in case of wooden heaters. During tests the temperature under the heater is less than 75 °C. But still when the heater is installed without a special Narvi installation base, the heat resistance of materials used in the floor structure has to be verified. If needed a Kota installation base has to be used to protect the floor.

Installation bases - Narvi Oy

With the aid of installations bases, the sauna heater can be installed in a sauna that has a wooden or paved floor, under which there is under floor heating or water insulation. The height of all installation bases can be adjusted. In the case that the floor is slanted, the adjustable legs can...

narvi.fi

 

[Mickfromaus]

Yeah. Saw those but they are ridiculously priced. Given you can buy a base there is something that can be “home made”.