In Jain temple architecture, the garbhagriha (the sanctum housing the Tirthankar idol) is typically a sealed inner chamber. The spaces used for walking or circumambulation (pradakshina) are generally outside or around the temple complex, not atop the sanctum itself.

Key points:

• The sanctum is usually below a dome or shikhara, sometimes on a raised plinth.
• Pilgrims perform pradakshina around the sanctum on the temple courtyard or a designated circumambulatory passage. This means walking around the sanctum, not walking above it.
• In many temples you will see a larger assembly hall (mandapa) or an outer prakara for walking, and sometimes a balcony or upper gallery in specific temple designs. However, walking directly on a level above the garbhagriha is not a standard feature in Jain temple practice.
• Differences between Digambar and Shwetambar traditions may appear in temple layout and height of structures, but the core practice of pradakshina remains centered on circulating around the sanctum rather than walking over it.

If you have a particular temple in mind, I can describe its exact layout and what walking spaces it provides, based on authentic Jain temple plans.