Cob for stone wall around a sauna stove

Hi everyone

We have have decided to build a stone wall / pile around our sauna stove for a few reasons. 1) beauty. 2) a barrier between the stove and wood wall 1' away and 3) to retain some of the heat long after we're no longer in the sauna

I want to hold the stonework together with cob, and I've made a few different mixtures for stucco, floor and other odd jobs - but I'm wondering if there is something more suited for a situation where they might get wet often from water overthrowing the stove. We have a few bags of lime crete around as well.

For fibre we have thatch and cattail.

Any pointers?

Thanks,
Rob