Traditional Olivine Diabase Sauna Stones 10–15 cm 20 kg

Big stones leave room for air and heat to move through a large stone mass, which is why wood stoves and big electric heaters often call for the 10–15 cm size. These are split-face olivine diabase: dense, hard-wearing and angular, so water spreads over a lot of hot surface. Load them in the bottom and middle of the pile, and if your manual asks for a finer top layer, finish with 5–10 cm stones. Rinse before use, keep the stack loose, and replace cracked stones as you find them.