What is an MF ceiling system?

An MF (metal furring) ceiling is a suspended plasterboard ceiling system using a grid of metal channels hung from the structural ceiling above. Primary channels run in one direction at 1200mm centres, supported by wire hangers. Furring channels clip to the primaries at 400mm centres, running perpendicular. Plasterboard is screwed to the furring channels. It is the standard system for commercial and high-quality domestic ceilings.

What spacing should primary channels be at?

Primary channels (also called top cross channels or main channels) should be at 1200mm maximum centres. They run perpendicular to the furring channels and are suspended from the structure above using adjustable wire hangers or direct fix brackets. In areas with heavy insulation loads, reduce spacing to 900mm.

What spacing for furring channels?

Furring channels (also called carrying channels or bottom channels) clip to the primary channels at 400mm centres for single 12.5mm or 15mm plasterboard. For double-boarded ceilings, 400mm centres are also standard. The plasterboard is screwed directly to the furring channels using 25mm or 32mm drywall screws at 150mm perimeter and 300mm field centres.

How far apart should wire hangers be?

Wire hangers (or rod hangers) should be at maximum 1200mm centres along each primary channel, and within 300mm of each wall. Each hanger must be securely fixed to the structural soffit above using an appropriate fixing (expansion anchor into concrete, or screw into timber joist). The hanger wire is threaded through the primary channel and twisted or clipped to secure.

What is perimeter angle on an MF ceiling?

Perimeter angle (or wall angle) is an L-shaped metal trim fixed around the entire room perimeter at the desired ceiling level. It provides edge support for the furring channels and a neat junction between the ceiling and walls. Fix at 450mm centres to the wall using screws and rawlplugs. It comes in 3m lengths. The furring channel rests on top of the angle at the perimeter.

MF Ceiling Calculator — Primary, Furring, Hangers & Angle

Calculate metal furring (MF) ceiling components: primary channels, furring channels, wire hangers and perimeter angle for suspended plasterboard ceilings.

Room Length

Along furring channel direction

Room Width

Along primary channel direction

Primary Price (optional)

Per 3.6m primary channel

Furring Price (optional)

Per 3.6m furring channel

Hanger Price (optional)

Per wire hanger

Angle Price (optional)

Per 3m perimeter angle

Board Price (optional)

Per 1200×2400mm plasterboard

How We Calculate This

This calculator determines all the metal framing components needed for a suspended MF plasterboard ceiling based on your room dimensions.

The formula

Primary channels = (Room width ÷ 1200mm + 1) rows × Room length

Furring channels = (Room length ÷ 400mm + 1) rows × Room width

For a 5m × 4m room: primaries = (4000÷1200+1) = 5 rows × 5m = 25m (7 × 3.6m). Furring = (5000÷400+1) = 14 rows × 4m = 56m (16 × 3.6m). Hangers = 5 × 5 = 25. Perimeter = 18m (6 × 3m).

Standard MF system spacing

Primary channels: 1200mm centres (900mm for heavy loads)
Furring channels: 400mm centres (clipped to primaries)
Wire hangers: 1200mm along each primary channel
Perimeter angle: Full room perimeter, fixed at 450mm cc

Frequently Asked Questions

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Last updated: March 2026

All calculations are estimates. Verify with your supplier.