Does anybody out there have any experience with using LECA (Lightweight Expanded Clay Aggregate) - aka Lytag as an insulant?
I'm wondering whether it could be substitued for Vermiculite / perlite in the Concrete Insulation Hearth mix...
Seems to me that it would provide a much more rigid load-bearing platform for the insulating hearth than the 'cork-like' vermivulite/perlite mix...?
