Getting the MF ceiling grid layout right before you start fixing saves time, material and the kind of problems that only become visible once the board is up. The setting-out process follows a defined sequence – perimeter frame first, primary channel positions marked from that, secondary channels worked out from the board module. Here’s how to approach it.

Start with the perimeter

The MF7 perimeter angle is the reference point for everything else in the grid. It fixes to the wall at finished ceiling height, runs continuously around the room perimeter, and sets the level that the MF5 primary channels will hang to. Getting this level and square before anything else goes up is the most important step in the whole installation.

Fix the MF7 at finished ceiling height using appropriate fixings for the wall substrate – frame fixings into masonry, self-drilling screws into metal stud, timber screws into timber stud. The MF7 should be fixed at no more than 600mm centres along its length. On longer walls, check level at multiple points rather than assuming the wall itself is level – particularly in older buildings where walls can deviate significantly over a run of several metres.

The internal corner junctions of the MF7 should be cut and lapped rather than mitred. A mitred corner looks neater but is weaker and harder to get tight. On acoustic builds, the perimeter angle junction with the wall should be backed with acoustic sealant before fixing, reducing the direct contact between the metal angle and the wall substrate.

Marking out the hanger positions

With the MF7 perimeter fixed and level, the next step is marking out the hanger positions on the soffit above. Hangers fix to the soffit and the MF5 primary channels hang from them, so the hanger layout determines where the MF5 runs.

MF5 primary channels run at 1200mm centres across the ceiling. Mark parallel lines on the soffit at 1200mm intervals, running in one direction across the room. The first line should sit no more than 150mm from the perimeter MF7 on the wall it runs parallel to. The final line on the opposite side should also sit within 150mm of that perimeter wall – if the room dimension doesn’t divide evenly into 1200mm bays, adjust the spacing slightly so the outer bays are equal and within the 150mm limit rather than running a narrow strip at one edge.

Along each MF5 line, hangers fix at 1200mm centres. The first hanger on each run should be no more than 150mm from the end of the channel – which in practice means no more than 150mm from the perimeter MF7. Mark each hanger position on the soffit before fixing anything. Doing this across the whole ceiling before you start drilling gives you a clear picture of the grid and lets you identify any clashes with existing services, beams or structural elements above.

Installing the hangers and MF5

Fix the hangers to the soffit at the marked positions. The fixing type depends on the soffit substrate – concrete soffits typically take a shot-fired or drilled expanding anchor, timber joists take a timber screw through the hanger strap or bracket, steel soffits take a self-drilling fixing. Check the hanger manufacturer’s load rating for the fixing type and span being used – on larger commercial ceilings this becomes a structural consideration.

With hangers in place, offer up the MF5 primary channels. The channel ends rest into the MF7 perimeter angle at each end of the run. The hangers clip or tie to the MF5 web at each fixing point. On nonius hanger systems the height is set by engaging the nonius clip at the correct slot – adjust all hangers on a given run to the same slot before moving to the next run, then check level across the whole grid with a long level or a laser level.

MF5 channels come in standard lengths and will typically need to be cut to length at the perimeter. Cut with tin snips or an angle grinder – the cut end rests into the MF7 so finish quality at the cut isn’t critical, but remove any sharp burrs that could be a handling hazard.

MF6 secondary channel layout

With the MF5 grid installed and level, the MF6 secondary channels clip to it via cross connectors at 600mm centres, running perpendicular to the MF5. The MF6 layout follows the board module – 600mm centres align with the standard board fixing requirement for single-layer plasterboard. For double-layer acoustic builds or where 2400mm boards are being run parallel to the MF6, reduce to 400mm centres.

The MF6 positioning should be worked out from the board joint positions rather than from an arbitrary starting point. Standard plasterboard is 1200mm wide, so board joints fall at 1200mm intervals across the ceiling. The MF6 channels at those joint lines need to be positioned so that both edges of adjacent boards land on the MF6 flange. This means the first MF6 from the perimeter should be positioned at half the board width – 600mm from the wall – so that board joints fall on the MF6 at every 1200mm thereafter.

In practice, rooms rarely divide into exact 1200mm modules. Work out the board layout on paper before fixing the MF6 – establish where the joints will fall, confirm the MF6 positions align with those joints, and identify whether the perimeter boards will need cutting. A small amount of planning at this stage avoids the situation where cut board edges land in the void between MF6 channels with no fixing.

Cross connectors clip over the MF5 web at each MF5/MF6 intersection. The MF6 slides into the connector from the end and is pushed along until it reaches the next connector. Check that each MF6 run is sitting level with its neighbours – a single connector that hasn’t fully engaged will drop that section of MF6 and create a visible hump in the finished ceiling.

Services and obstructions

The ceiling void created by the hanger system needs to be co-ordinated with any services running within it before the MF6 goes in. Electrical cables, HVAC ductwork, sprinkler pipework and data runs all need to be in position and supported before the secondary grid closes up the void. Retrofitting services through a completed MF ceiling grid is significantly more difficult.

Mark the positions of any downlights, extract fans or access panels on the MF6 grid before boarding starts. Downlights in particular need to be positioned so they don’t land on an MF6 channel – the channel positions should be adjusted slightly if needed to give clear space for the fitting. On acoustic ceilings, downlight positions should be identified early so acoustic downlight covers can be ordered with the rest of the materials.

Boarding sequence

Board fixes to the MF6 flanges with drywall screws at 230mm centres along the channel. The first sheet should be offered up square to the room – check the MF6 layout is genuinely square before committing to the first board position, as any error in squareness compounds across the ceiling. On larger ceilings, snap a chalk line along the first MF6 run before boarding starts as a reference.

Board joints should be staggered – on single-layer ceilings, alternate rows should offset by at least half a board length. On double-layer acoustic builds, the second layer should offset joints from the first layer in both directions.

FAQ

What centres should MF5 primary channels be fixed at? 1200mm centres, with the first and last channel no more than 150mm from the perimeter wall.

How far apart should hangers be along the MF5? 1200mm centres along the MF5 run, with the first hanger no more than 150mm from the end of the channel.

Should MF6 always be at 600mm centres? 600mm centres for standard single-layer board. Reduce to 400mm for double-layer acoustic builds or where 2400mm boards run parallel to the MF6.

How do I handle rooms that don’t divide into 1200mm modules? Work out the board layout first. Position the MF6 so board joints land on channels throughout, and accept cut boards at the perimeter. Adjust the first MF6 position from the wall if needed to keep the main field boards uncut.

What’s the best way to check the MF5 grid is level? A rotating laser level is the most reliable method on larger ceilings. On smaller rooms a long spirit level across multiple MF5 channels works well. Check in both directions across the grid before the MF6 goes in.For MF ceiling components including MF5, MF6, MF7 and cross connectors, visit the MF ceiling system category. For the full metal framing range including metal stud and track and wall lining systems, visit the metal framing category.