Raised Access Floor: The Void That Runs the Office
A raised access floor is a grid of removable panels sitting on adjustable pedestals above the structural slab, creating a shallow service void for power, data and sometimes air — so cabling can be rerouted later by lifting a tile rather than opening a ceiling.
By Dhruv Agarwal · · 2 min read
Why it matters on a fit-out project
The raised floor is invisible in every photograph of a finished office and determines much of how the office actually works. It sets where a desk can have power, how easily a layout can change in three years, and — because it eats slab-to-slab height — how tall the finished space feels.
It is also one of the earliest decisions. Void depth has to be fixed before the ceiling design is settled, because the two are competing for the same dimension.
How it is specified in practice
| Parameter | Typical position | Why |
|---|---|---|
| Void depth | 100-150mm for power/data | Deeper if the void is also an air plenum |
| Panel core | Calcium sulphate or steel-encapsulated chipboard | Calcium sulphate is denser, better acoustically, non-combustible |
| Panel size | 600 × 600mm | Matches ceiling grid and workstation planning |
| Loading grade | Medium general, heavy at server and storage | Concentrated load, not just distributed |
| Pedestal | Adjustable, bonded to slab | Bond quality determines whether the floor rocks |
| Finish | Carpet tile, vinyl or bare with loose lay | Carpet tile is standard for offices |
| Fire stopping | At every shaft and compartment line | The void is continuous and crosses compartments |
Common mistakes
- Deciding void depth after the ceiling. Floor void, structural zone, service zone and ceiling void all share the slab-to-slab dimension. Resolve them together at concept, not sequentially.
- Specifying one panel grade everywhere. Server rooms and storage need a heavier grade, and the fit-out route itself takes loads the finished office never will.
- Ignoring the slab surface. Pedestals bond to the slab. Dusty, uneven or laitance-covered concrete produces a floor that rocks from day one.
- Forgetting fire stopping in the void. It is a continuous horizontal cavity and must be stopped where it crosses compartment lines under NBC 2016 Part 4.
- Cutting tiles badly at the perimeter. Perimeter cuts are where a floor looks cheap and where edge support most often gets missed.
Standards referenced
Imposed floor loading is derived from IS 875 (Part 2). Compartmentation and fire stopping through the floor void fall under NBC 2016, Part 4.
Standards referenced
- IS 875 (Part 2) — Imposed loads
- NBC 2016, Part 4 — Fire and life safety