# Raised Access Floor Calculator: Panels, Pedestals and Stringers

> A raised access floor is a grid of removable panels on adjustable pedestals above the slab. On a 600 × 600 mm grid, the panel count follows from the floor area, a pedestal sits at every grid intersection, and stringers, where used, run along the grid lines. The quantities come straight from the room size.

## What it calculates

For a rectangular room with a raised access floor on a 600 × 600 mm grid, the calculator
gives the quantity of each main component:

- **floor panels**, 600 × 600 mm, including wastage;
- **pedestals**, one at every grid intersection, labelled with the finished floor height;
- **stringers**, as running metres and 1.2 m pieces, if the system uses them;
- **perimeter edge trim**, in running metres;
- **cable cut-outs or grommets**, as entered.

It is a quantity take-off for budgeting and for checking a supplier's list, not a floor
design.

## Inputs

**Room length** and **room width** are the inside dimensions of the area to be floored, in
metres.

**Panel size** is fixed at 600 × 600 mm, the common modular size for office raised floors.

**Stringers** can be none, for a stringerless system where panels sit directly on the
pedestal heads, or with stringers, which link the pedestal heads along every grid line.

**Cable cut-outs / grommets** is the number of openings in panels for power and data to come
up to desks, floor boxes or equipment. Count them from the furniture and power layout.

**Finished floor height** is the height from the slab to the top of the panel. It does not
change any quantity; it labels the pedestals so the list is complete.

The **assumptions** panel holds the wastage on panels.

## Method

The grid geometry fixes every quantity:

| Component | Rule | Formula |
| --- | --- | --- |
| Floor area | Length × width | L × W |
| Panels | One for every 0.36 m², plus wastage | ceil(L × W ÷ 0.36 × (1 + wastage)) |
| Pedestals | One at every grid intersection | (ceil(L ÷ 0.6) + 1) × (ceil(W ÷ 0.6) + 1) |
| Stringer run | Along every grid line, both ways | (ceil(W ÷ 0.6) + 1) × L + (ceil(L ÷ 0.6) + 1) × W |
| Stringer pieces | 1.2 m lengths | ceil(stringer run ÷ 1.2) |
| Edge trim | Around the room | 2 × (L + W) |
| Cut-outs | As entered | number entered |

A grid of 600 mm bays across a length L has ceil(L ÷ 0.6) bays and one more grid line than
bays, because there is a line at each wall. Pedestals sit where the lines cross. The same
lines carry the stringers, so the stringer run is the number of lines in each direction times
the length they span.

## Assumptions

| Assumption | Default | Notes |
| --- | --- | --- |
| Panel size | 600 × 600 mm | The only size offered |
| Wastage on panels | 5% | Perimeter cuts and spares |
| Stringers | None | Selected by the system designer |
| Stringer length | 1.2 m | Two grid bays per piece |
| Grid start | At one wall | A pedestal line along each wall |

Wastage is applied to panels only. Pedestals and stringers are counted from the grid, and
the installer adds extra supports where needed.

## Limitations

- **Rectangular rooms only.** Split other shapes into rectangles and add them; irregular
  rooms need more wastage and more perimeter supports.
- **The grid is not set out.** Where the grid starts decides the size of the cut panels at
  the walls. A designer centres the grid so cut panels are not thin strips.
- **Obstructions are ignored.** Columns, risers and floor openings need extra pedestals and
  cut panels around them.
- **No ramps, steps or edges.** A change in level at the entrance, a ramp or an exposed edge
  needs its own fascia, nosing and supports.
- **No load class, pedestal type or bracing.** Panel load class, pedestal type, adhesive or
  fixing, bracing and earthing are chosen by the designer to EN 12825 and the manufacturer's
  tested system. This calculator gives no load values.
- **No services.** Floor boxes, air grilles for underfloor air and cable trays in the void
  are measured separately.

## Worked example

A 12 m × 9 m office floor with 600 × 600 mm panels, no stringers, 20 cable cut-outs and a
300 mm finished floor height, at the default 5% wastage:

| Component | Calculation | Quantity |
| --- | --- | --- |
| Floor area | 12 × 9 | 108 m² |
| Panels | ceil(108 ÷ 0.36 × 1.05) | 315 |
| Pedestals | (ceil(12 ÷ 0.6) + 1) × (ceil(9 ÷ 0.6) + 1) = 21 × 16 | 336 |
| Stringers | Not selected | none |
| Perimeter edge trim | 2 × (12 + 9) | 42 m |
| Cable cut-outs / grommets | As entered | 20 |

The 336 pedestals are for a 300 mm finished floor height; the supplier chooses the pedestal
range that suits it once the panel thickness is known.

If the system needs stringers, select "With stringers". The stringer run becomes
16 × 12 + 21 × 9 = 381 m, which is 318 pieces of 1.2 m.

Twelve metres divides into exactly 20 bays and nine metres into exactly 15, so in this room
the grid fits without cut panels if it starts at a wall. The 5% wastage is then mostly spare
panels for later replacements.

## How engineers use it

A designer or MEP engineer uses a take-off like this when a raised floor is first proposed,
often to compare it with surface trunking or ceiling distribution for power and data. The
area, panel count and cut-out count are enough for an early budget from suppliers.

Once the layout is drawn, the floor is planned in more detail. The grid is set out on the
plan against the walls, columns and core. Areas that need a heavier panel grade, such as
server rooms, storage and goods routes, are marked. Floor boxes and cut-outs are placed from
the furniture and power layout, and the void depth is coordinated with the floor-to-ceiling
height, the door thresholds, the lift lobby levels and any underfloor air. The manufacturer's
system then sets the pedestal type, any bracing or stringers, and the fixing to the slab.

## When a professional design must replace it

Use the calculator to estimate quantities, compare options and check a supplier's take-off.
Replace it with a designer's raised floor layout and the manufacturer's tested system before
ordering or installing. That design chooses the panel load class for each area, the pedestal
type and height, bracing and stringers, earthing of the floor, and the details at ramps,
edges and penetrations, using EN 12825 and the manufacturer's test data.

## Frequently asked questions

### How many pedestals does a raised floor need?

On a 600 × 600 mm grid there is one pedestal at every point where grid lines cross, including along the walls. For a 12 × 9 m room that is 21 lines one way and 16 the other, so 336 pedestals. The count rises at columns, cut-outs and edges, where the installer adds extra supports for cut panels.

### Do I need stringers?

Stringers are horizontal members that link pedestal heads along the grid lines. They make the grid stiffer and help keep panels in place when many are lifted at once. Whether a floor needs them depends on the system, the floor height, the loads and how often panels will be lifted, so the designer decides using the manufacturer's tested system.

### What panel grade should I use?

The panel load class is chosen by the designer for each area, using the loads the floor will carry and the manufacturer's test results to EN 12825. General office areas, server rooms, storage and routes used by trolleys usually need different grades. This calculator counts panels only and does not recommend a grade.

### Why add wastage to the panel count?

Panels at the walls and around columns are cut to fit, and an off-cut is rarely usable elsewhere. A few spare panels are also kept for later replacements. The default is 5%; raise it for small rooms, narrow corridors or rooms with many columns and cut-outs.

### What does finished floor height change in the calculation?

Nothing in the quantities. It labels the pedestals, because the pedestal height is roughly the finished floor height less the panel thickness, and the manufacturer supplies pedestals in height ranges. Taller floors may also need bracing or stringers, which the designer confirms.

## Sources

- [EN 12825](https://standards.cencenelec.eu/ords/f?p=CEN:105) — Raised access floors

---

Source: https://hagerstone.com/calculators/raised-floor-calculator