@d0e09e5d @e5c81548 i think the under layer will be much more important. We did electric radiant on a (uninsulated) slab and then tile over, and ended up leaving it turned off because it took forever to heat up and seemed very inefficient. Look into it, but i think your tile layer will be able to be thinner (more responsive) than the concrete would have to be, and self leveling concrete isn’t very durable if you are moving heavy pots around etc. 

 @d0e09e5d @e5c81548 btw if you’re more interested in the thermal mass for a greenhouse than having warm feet, it might be a lot cheaper to just heat up some tanks of water (black and in the sun ideally) and call it good 

 @9d2d61ac @e5c81548 yeah, that would be ideal. But not in my greenhouse project. You know, little over one square meter a module and half a meter tall. Preferably on wheels, if I can pull that off 😂 

 @d0e09e5d @e5c81548 ah i see. I’d do tile then, it will be easier to do and lighter to move around. You could always lay a couple slabs of stone on the tile to add some mass if needed. Put up a pic if you have any of it built or a drawing 

 @d0e09e5d btw build it so you can use a pallet Jack and you won’t have to worry about the weight as much.