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FOR DRYLINING AND CEILING CONTRACTORS

MF ceiling: components, centres and spacings

An MF ceiling is a suspended plasterboard ceiling on a concealed metal grid. Primary channels hang from the soffit on hangers. Ceiling sections fix underneath them at right angles, and the plasterboard screws to the ceiling sections. The finished ceiling is flat, with a void above it for services.

MF stands for metal furring. The codes below are British Gypsum's Gypframe names, which most of the trade uses. Other manufacturers make equivalent systems with similar codes, such as Speedline's SSMF range.

MF ceiling components

  • MF7 primary support channel: the main runners, hung from the soffit.

  • MF5 ceiling section: the furring sections fixed under the MF7, which the board screws to.

  • MF6 perimeter channel: fixed around the walls to carry the ends of the MF5. Speedline's equivalent is the SSMF6A.

  • MF8 strap hanger: hangs the MF7 from the soffit. For deeper voids, or where a plaster finish is specified, FEA1 steel angle is used instead.

  • MF12 soffit cleat: fixes the hanger to a concrete soffit. MF11 nut and bolt: connects the hanger to the primary channel.

  • MF9 connecting clip: an alternative way to fix the MF5 to the MF7.

  • Wafer head jack-point screws (13mm): for fixing the framework together. Drywall screws: for fixing the board, with the length set by the number of layers.

Typical MF ceiling centres and spacings

Maximum ceiling load

30kg/m²

35kg/m²

40kg/m²

60kg/m²

With Gyproc plasterboard linings, British Gypsum puts the MF5 ceiling sections at a maximum of 450mm centres. The spacing of the hangers and the MF7 channels depends on the weight of the ceiling, including board, insulation and plaster finish:

Hanger centres

1200mm

900mm

1200mm

1200mm

MF7 centres

1200mm

1200mm

900mm

600mm

Other spacings from the British Gypsum specifications:

  • Perimeter channel fixed to the wall at 600mm centres.

  • Strap hangers for voids up to 1000mm. Use steel angle for anything deeper.

  • Board screws at a maximum of 230mm centres, closing to 150mm at board ends and around the perimeter.

  • The MF5 and MF7 screwed together with two wafer head jack-point screws at each crossing, particularly with plain plasterboard linings.

Fire-rated specifications can be tighter. One British Gypsum 120-minute specification, four layers of 15mm FireLine, uses MF5 at 400mm centres and MF7 at 600mm centres. So treat the figures above as typical, and take the actual centres from the system specification for the job.

What to check before you price an MF ceiling

  • The specification. Board type, number of layers, fire and acoustic rating. These set the MF5 and MF7 centres, the screw lengths and how much board you need.

  • The void depth. It decides whether strap hangers will do or you need steel angle.

  • The weight. Insulation laid over the grid, heavy board and plaster finish all add load, and the load sets the hanger and MF7 centres. Light fittings and other fixtures need fixing into the grid or supplementary framing. Ducting must be supported from the structure, not the ceiling.

  • The perimeter and any changes of level. Bulkheads and level changes take extra MF6 and MF5 and more labour.

  • Partitions under the ceiling. If a stud partition fixes to the MF grid, the MF sections need to run parallel to it, which can mean extra MF5.

For the board itself, see plasterboard thickness and sizes.

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Common questions

What is an MF ceiling?

A suspended ceiling with a concealed metal grid of primary channels and ceiling sections, lined with plasterboard. The finished ceiling looks the same as a solid plasterboard ceiling.

What does MF stand for?

Metal furring. It refers to the furring sections the board fixes to.

What centres are MF5 sections at?

A maximum of 450mm with Gyproc plasterboard linings in British Gypsum's system. Some fire-rated specifications use 400mm. Always follow the specification for the job.

Is an MF ceiling the same as a suspended grid ceiling?

No. A grid ceiling has an exposed grid with lay-in tiles. An MF ceiling has a hidden grid lined with plasterboard, which is then jointed or skimmed.

This page is general guidance from manufacturers' published information. Spacings depend on the system, the board and the loads. Always work to the specification and the manufacturer's current literature.

We're building QFitout, drylining quoting software that applies these allowances for you when you price a job.

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