The storage floor of the Jedi Temple was located below the Temple proper and considered below "ground level" on Coruscant as it was lower than the rooftops of nearby buildings. Of simple design, the area was accessed by the various service corridors and turbolifts that ran throughout the Temple.
Erected beneath the Temple Ziggurat, the storage floor was destroyed and rebuilt several times in the Temple's long history, seeing completion in 1000 BBY under the Galactic Republic. Because of the size of the Jedi Order and the amount of beings it had to feed and clothe, the Order had to import many items into the Temple, including linens, foodstuffs, and supplies that needed to be stored out of the way in bulk. Visited infrequently by most Jedi, the storage floor was utilized by the Temple employees when moving supplies around.
When the Republic was transformed into the Galactic Empire and the Order was disbanded, the Temple was laid siege by Darth Vader and the 501st Legion. Unoccupied, the storage floor escaped the carnage but did not fall out of use. Scoured of any valuables, High Inquisitor Malorum spread rumor that the storage floor was being used as an Imperial prison for captured Jedi in hopes that survivors of Order 66 would attempt a rescue.
Upon hearing of the rumor, Jedi Knight Fy-Tor-Ana came out of hiding and traveled to Coruscant in order to investigate the Temple ruins. While she never was able to make it to the Temple, ex-Jedi Ferus Olin did enter the ancient edifice and was able to debunk the rumor; in truth of storage floor was being used to hold the lightsaber hilts of the fallen Jedi, including the weapon of Tru Veld. Reluctantly leaving the lightsabers, Olin fled the pursuit of stormtroopers guarding the trap by exiting through a rear doorway.
The Temple sat in the hands of the Sith for several decades, guarded by the trusted Shadow Troopers of the Empire. When Sidious and Vader were slain, the Empire lost balance and was eventually ousted from Coruscant. During the Yuuzhan Vong War Coruscant was devastated by terraforming, causing the Temple to crumble and reveal parts of the foundation. When the Galactic Alliance reclaimed the world, Chief of State Cal Omas, ordered the Reconstruction Authority to rebuild the ancient edifice as a gift for the great sacrifices made by the Order against the Yuuzhan Vong.
In full use again, the storage floor was mostly the same as it had been since the time of the Old Republic, with some hallways sealed off or built over. In 43 ABY, Chief Natasi Daala ordered the Temple sieged by Mandalorians led by Belok Rhal, trapping the Jedi within. Desperate for a way out of the besieged edifice and without power or water, the Masters sent Initiates into the storage floor and other lower levels to search for any passage out; or if they couldn't get out, a space that they could smuggle material in. Haste was encouraged as the Halls of Healing were running out of a tranquilizer used to contain a group of Jedi who had been crippled by an enigmatic madness. As High Council member Octa Ramis and her Padawan Seha Dorvald searched the lower levels, Ramis made a discovery in the storage floor. Summoning Dorvald, the two bore witness to groups of rats flowing into the Temple, sent by Knight Leia Organa Solo with vials of medicine strapped to their backs.
Unliike the public areas of the Temple, the storage floor was built to service utilitarian needs and therefore lacked much of the elegant beauty of the rest of the structure. Comprised of bare parallel hallways lined with storage rooms of various sizes, the halls were large enough to allow service vehicles to move freely to and from the storage vaults and the lower level service hangars.
Largely the same, the chambers contained rows of shelving upon which the basic items need by the Temple's occupants were stored, including linens, training equipment, old droids, and soap. One of the larger storerooms was used to house all of the herbs and vegetables needed to supply the refectories that could not be grown at the Temple itself. Connected to the second service tunnel on this level, it had a separate delivery system than the other storage rooms, connecting them with the refectory kitchens. Instead of using turbolifts, the Jedi serving in the kitchens would select an item from their datascreen, and the item they selected would be moved from its shelf by a droid and placed in a vertical lift. Small, and running on a compressed-air system, the selected item would be blown up the shaft and into a temporary zero-gravity immersion well, where the Jedi could grab it and use it in the kitchens.