One of the most important components to any good sauna is the type of sauna rocks used in the heater. Whether you are a purist using a wood burning stove or someone who has embraced the more modern electric heater it is important that you use the proper sauna rocks. Mikkel Aaland points out in the book, “Build Your Own Sauna and Sweat” Copyright 2011 by Mikkel Aaland all rights reserved, every time you heat up a rock it is the equivalent of 1000 years of natural erosion so only the strongest rocks can survive many heat ups required for a sauna heater.
The leading manufacturers recommend periodite sauna rocks which is a quarried rock from Finland, but Certain North American rocks work as well. Basalt is excellent. So is hornblende, found in many parts of North America. No matter which style of heater you use the intent is to allow the rocks to heat the air as much as possible. and by splashing water over them one can incorporate humidity into the sauna climate.
Sauna rock placement is very important to the overall sauna experience as well. It is important to stack your largest rocks tight around the perimeter of the rock chamber. Then smaller rocks would be looser stacked in the middle to allow for air flow. With European Style full contact electric heaters you should stack the smaller rocks between the coils. Then one layer of larger sauna rocks across the rim of the rock chamber that will allow you to splash water over them combine humidity into the sauna.
This illustrates how the choice of sauna rocks and their positioning really are the centerpiece of the entire sauna experience. Rocks are the mechanism that allows one to control their climate which is what makes the Traditional Finnish Sauna so unique compared to other heat therapy methods like steam rooms or infrared saunas.