Was the idea of a raised floor used as early 350 BC?

Did the title of this blog post seem interesting? “Was the idea of a raised floor used as early as 350 BC?” Because technically this is TRUE! However, it is not quite the same as todays “raised ACCESS flooring” but the idea is very much the same - allow me to explain….

If you are here reading this post, hopefully you have read the other posts or have toured our webpage and know what a raised access floor actually is, more importantly what the plenum space is that’s created by the raised access floor. For those of you who have not, here is a really quick explanation…..A plenum space is the area under the raised access floor, between the slab and the underside of the floor system. Typically we see this plenum space achieve heights of 12-18” - when used for under floor air distribution.

Now, back to the title of this post, its totally true, early civilizations dating back to 350 BC actually used a form of raised floor and a plenum space to heat their bath houses, temples, and in some cases (if you were VERY wealthy) their homes! The Romans actually built up their floors by constructing large pillars (pedestals) and actually laying their floor right on top. This would create a plenum space whereby a large fire/furnace would pull heat into the plenum space and the hot air and smoke would actually flow under the floor and into the walls creating a type of radiant style heating - this literally paved the way for what we have today in our central heating system! The air that was pulled into the plenum space and into the walls would be vented though chambers leading up to the roof, creating a form of exhaust.

A “hypocaust” is a word used to describe a type of heating system within a space that produces heat and funnels it through the plenum space of a building or room, the word is derived from the Ancient Greeks, “HYPO” meaning “UNDER” and “CAUST” meaning “BURNT” (*1)

It is believed that the earliest known reference to the ancient plenum design dates back to 350 BC, at the Temple of Ephesus. However, there is a case for these plenum designs to date back even further….Explorers believe they had uncovered a type of HYPOCAUST at one of their excavations in Pakistan, which they believe to have pre-dated the Romans by over 2000 years! (*2)

In todays world, the need for heating within the plenum space is typically non-existent, we use these plenum spaces to cool and provide conditioned air to the occupants. The heat generated by people, computers, televisions, perimeter glazing means that we usually supply cool, conditioned air within the plenum space and use supplemental heating for the perimeter only.

In closing, I may have mis-lead you slightly with the title, as I was really talking about a plenum space more so than a raised floor, however, the idea that the Romans or early civilization utilized a raised floor and plenum space is entirely accurate. These early pioneers of mechanical and architectural building methodology is essentially the precursor to what we now have today when we discuss raised flooring and under floor air distribution.

Thank you to everyone who took the time to read this blog post, please keep an eye each week as we try to bring a new post about the products and services we are part of! Take care and we hope to see you back here again!

Best regards,

Russell J. Cook, Dip. ME, GSC

1.) “Hypocaust / architecture” Encyclopedia Britannica.

2.) About Roman Baths, William Smith

Example of a “Hypocastum”