MF Ceiling Components: MF5, MF6, MF7 and Hanger Types – Complete Parts Reference

An MF ceiling system is only as good as the components holding it together. If you’re pricing a job, checking a specification or ordering for the first time, this guide breaks down every part of a standard MF ceiling – what each component does, its dimensions, and how the pieces connect.

What is an MF ceiling system?

An MF (metal frame) ceiling system is a suspended ceiling construction used in UK drylining. It creates a fully independent ceiling structure below the soffit above, using a grid of metal channels fixed back to the structure via hangers. Plasterboard is then fixed to the underside of the grid. The system is specified on acoustic, fire and services grounds – anywhere a standard plasterboard direct-fix or timber batten ceiling won’t meet the requirement.

The system relies on a small number of standard components that connect in a specific sequence. Getting that sequence right at the ordering stage saves a lot of time on site.

The Core Components

MF5 – Primary Channel

The MF5 is the main load-bearing channel that spans across the ceiling. It runs in one direction, fixed to the structure above via hangers at 1200mm centres. Everything else in the system hangs off or clips to the MF5.

Typical MF5 dimensions are 60mm x 27mm, rolled from 0.5mm galvanised steel. The channel profile is hat-shaped in cross-section, which gives it the rigidity to span between hanger points without deflection. On acoustic builds the MF5 spacing is often reduced to 1200mm maximum – but in practice many contractors run them at 1000mm to be safe, particularly on larger spans.

The MF5 doesn’t touch the plasterboard directly. It’s the first tier of the grid, sitting closest to the soffit.

MF6 – Secondary Channel

The MF6 is the secondary channel that runs perpendicular to the MF5, sitting below it and clipping into it via cross-channel connectors (sometimes called MF9 connectors or simply cross tees, depending on the manufacturer). The MF6 runs at 600mm centres for standard single-board construction.

MF6 dimensions are typically 60mm x 19mm – shallower than the MF5 because it doesn’t carry the full span load. The plasterboard fixes directly to the underside of the MF6 flanges, so the soffit level of your ceiling is determined by the underside of the MF6.

For 400mm board joints or acoustic specifications requiring closer board fixing, MF6 centres can be reduced to 400mm. When specifying acoustic builds, check whether the build-up calls for a double layer of board – if so, the second layer offsets the joints, which is easier to manage at 400mm MF6 centres.

MF7 – Perimeter Channel

The MF7 is an angle section fixed to the perimeter walls at ceiling level. It forms the box that the MF5 and MF6 grid sits within, and provides the fixing point for the ends of the primary and secondary channels.

MF7 dimensions are typically 19mm x 30mm. It’s fixed to the wall at the finished ceiling height and runs continuously around the room perimeter. The MF5 channels rest into the MF7 at each end rather than being fixed hard – this allows for slight movement and prevents stress cracking at the ceiling-wall junction, which is particularly important in acoustic builds where vibration isolation is part of the design intent.

The MF7 also acts as a visual stop – with the correct installation sequence, the plasterboard edge sits neatly against the wall with the MF7 hidden behind the board.

Hanger Types

Hangers are what connect the MF5 grid to the structure above. The choice of hanger depends on what you’re fixing into and how much height you need to take up.

Flat strap hanger – the most common type for typical ceiling voids. A flat steel strap fixed to the soffit above (concrete, timber joists, steel) and folded down to clip or tie onto the MF5. Straightforward to install and adjust, suitable for voids up to around 150-200mm.

Rod hanger – used where the ceiling void is deeper, typically 200mm and above. A threaded rod drops from a fixing plate at the soffit to an MF5 bracket below. The threaded rod allows precise height adjustment, which is useful on commercial jobs where level is critical across large areas.

Spring toggle or Rawlplug type fixing – used in retrofit situations where the soffit is hollow or has limited bearing. Less common in new build but regularly encountered in refurb.

The hanger spacing follows the MF5 – hangers at 1200mm centres along each primary channel run, with the first hanger no more than 150mm from the end of the channel.

Hanger clips and MF5 brackets vary by manufacturer. The Siniat, Knauf and British Gypsum systems are all broadly compatible in principle but the clips aren’t always interchangeable in practice. Specify one manufacturer’s system per project if you can.

Cross-Channel Connectors (MF9)

The cross-channel connector (also referred to as the MF9 or just a cross tee) is what joins the MF6 secondary channels to the MF5 primary channels at each intersection. The connector clips over the MF5 web and the MF6 slides into it.

These connectors are what allow the MF6 to hang below the MF5 rather than running alongside it, giving the grid its two-tier structure. The offset between MF5 and MF6 is typically around 27mm – which is worth factoring in when calculating total ceiling void depth.

Nonius Hangers for Acoustic Systems

On acoustic ceiling builds – typically where the MF ceiling is being used to meet Part E requirements rather than just for appearance or services integration – a nonius hanger is often specified in place of a standard strap hanger. The nonius hanger has a slotted upper section that allows the lower clip to hook in at incremental heights, making level adjustment faster and more repeatable across a grid.

More importantly, the nonius hanger is designed to allow slight isolation between the structure and the MF5 grid. This reduces direct vibration transmission – relevant when the acoustic build-up relies on the ceiling being independently constructed from the floor or ceiling above.

Putting It Together – The Build Sequence

The components connect in a fixed order: MF7 perimeter angle first, then hangers installed at 1200mm centres in both directions, then MF5 primary channels suspended from the hangers, then MF6 secondary channels clipped to the MF5 via cross connectors at 600mm (or 400mm) centres. Plasterboard then fixes to the MF6.

The total depth from soffit to finished board face depends on hanger length, but a standard installation with a moderate void will typically add 80-120mm to ceiling height loss. Services integration (lighting, HVAC, sprinklers) will push that higher and needs to be co-ordinated before the MF5 level is fixed.

Specification Tables

Common Ordering Mistakes

The most common ordering error is buying MF5 and MF6 without accounting for the cross connectors. The connectors aren’t always included in ceiling system packs and can hold up a job if they’re missed. Count your MF5/MF6 intersections and order connectors for each one.

The second common issue is undersizing the hanger length. Measure the actual void from soffit to finished ceiling level before ordering, allow for the hanger fixing plate height, and add a small tolerance. Running short on hanger length mid-install is avoidable.

FAQ

What is the difference between MF5 and MF6? The MF5 is the primary load-bearing channel that spans between hanger points at 1200mm centres. The MF6 is the secondary channel that runs perpendicular to the MF5 at 600mm centres and provides the surface to fix plasterboard to.

Can you use timber batten instead of MF6? On simple direct-fix ceilings, timber is common. But once you’re building an acoustic or fire-rated suspended ceiling system, the MF ceiling components are specified precisely because of their acoustic and structural performance within tested build-ups. Substituting materials outside the tested system invalidates the performance claim.

What spacing should MF6 be fixed at? Standard 600mm centres for single-layer board. 400mm centres for double-layer board or when using 2400mm boards at right angles to the MF6 run.

Are Knauf and Siniat MF ceiling components interchangeable? The dimensional profiles are broadly similar across manufacturers, but clips and connectors are not reliably interchangeable. Stick to one system per project to avoid on-site compatibility issues. For full details on our MF ceiling range – including MF5, MF6, MF7 channels and compatible hangers – visit the MF ceiling system category. If you’re specifying a full metal framing package, the metal framing main category covers everything from metal stud and track through to resilient bars and wall lining systems.