Suspended Ceiling Installation (Including Grid System)

The whole system is dry construction. Nothing is mixed, nothing has to dry, and the ceiling is finished as soon as the last tile goes in. A typical build-up looks like this:

• Wall angles screwed to the walls around the whole room
• Hangers fixed into the original ceiling, usually wire hangers with an adjustable spring clip or rigid adjustable hangers
• Main runners hung from the hangers
• Cross tees that complete the grid, usually in a 600 × 600 mm or 600 × 1200 mm module
• Tiles that simply sit loose in the grid, with no adhesive or filler

The grid is made of galvanised steel, so in a normal indoor environment it lasts a very long time. What wears is mainly the surface of the tiles, and you can replace those one at a time.

Fitting a grid ceiling looks simple, but a good result depends on careful setting out. An experienced installer usually works roughly like this:

1. Set the ceiling height to allow for the pipes, cables, lights and ventilation above it, then mark it around the room with a laser level.
2. Plan the grid so that the cut tiles along opposite walls are about the same width, rather than a thin strip along just one wall.
3. Screw the wall angles to the walls along the marked line.
4. Fix the hangers into the ceiling with anchors suited to what it is made of: concrete, hollow clay blocks and timber joists each need a different fixing. Space the hangers according to the manufacturer's instructions, often roughly every 1.2 m.
5. Hang the main runners, level them and add the cross tees.
6. Prepare the positions for light fittings, ventilation grilles and access points.
7. Lay in the tiles, cut the edge tiles to size and finally check that the whole ceiling is level.

Tiles should only go in once the wet trades in the room are finished, the windows are fitted and the space is dry. Mineral fibre tiles react to damp air and can sag. Manufacturers therefore usually recommend leaving them in the room for a while before installation so they can adjust to its temperature and humidity.

Grids usually come in two visible profile widths. A 24 mm grid (often called T24) is wider, stiffer and easier to work with. It suits offices, corridors and plant rooms. A 15 mm grid (T15) is narrower, so the grid is less noticeable and the ceiling looks lighter. People choose it where appearance matters. With both systems, the tiles lift out just as easily.

When choosing tiles, think about what the room will be used for:

• Mineral fibre tiles are the standard choice for ordinary offices and corridors, with reasonable acoustics and easy replacement
• Acoustic tiles absorb more sound and cut down echo, which you will notice in open-plan offices, meeting rooms, classrooms and waiting rooms
• Moisture-resistant tiles belong in rooms with higher humidity, such as staff kitchens, washrooms or basements
• Hygiene tiles with a washable surface are used in clinics and food premises
• Smooth-faced tiles suit people who want a clean, modern look

Why not plasterboard instead? A plasterboard ceiling is solid and continuous and looks like a traditional ceiling, but you can only reach the cables through access hatches or by cutting a hole. A grid ceiling opens anywhere without damage. The reverse is also true: if you want a smooth ceiling without a visible grid in your living room, tiles will not give you that look.

Plan the light fittings, cable outlets and ventilation grilles before the grid goes up. Otherwise the finished ceiling has to be opened up again and the grid altered. The usual choices are LED panels sized to fit a tile, downlights in specially cut tiles, or linear lights. Along windows, a special edge detail can hide a curtain track or an LED strip.

The grid itself usually carries lightweight panels. Heavier light fittings, fans or ventilation units need their own hangers fixed to the original ceiling so they do not make the grid sag. Check what both the grid manufacturer and the fitting manufacturer say about this.

Any wiring above the ceiling must be done by a qualified electrician, and new circuits should come with the relevant test certificate when the job is handed over. In commercial premises there may be fire safety requirements for the tiles' reaction-to-fire class or for the fire resistance of the ceiling. Check these in the project documents or with the designer. If the work is linked to a change of use of the space, ask your local building authority whether you need approval. In a block of flats, tell the building management or owners' association before anyone drills into the ceiling.

How demanding the job is, and therefore what it costs, depends on the space. The job is easier with:

• A large rectangular room without alcoves or columns
• A solid concrete ceiling that holds fixings well
• A normal room height where work can be done from a mobile scaffold tower
• A finished plan for lights and services before work starts

The job gets harder with:

• An irregular floor plan, angled walls, columns and lots of cut tiles
• A deep suspension or a high ceiling that needs longer hangers and larger scaffolding
• A ceiling that holds fixings poorly, such as old hollow clay blocks
• Many openings for lights, sprinklers and ventilation
• Working while the premises stay open, which means cleaning up and working in sections

Think about headroom too. Besides the grid itself, you need space above it for light fittings and services. In lower rooms in older buildings, it is worth checking beforehand whether the services can be routed so the ceiling does not have to drop further than necessary.

• Too few hangers or the wrong fixings. Over time the ceiling sags, especially under light fittings, and tiles start falling out of the grid.
• A badly planned grid. A thin strip of tiles ends up along one wall, which looks odd and is awkward to fit.
• Tiles fitted in a damp building. They move, sag or develop stains.
• The wrong tiles for the room. Standard mineral tiles do not cope in a washroom and do nothing for the echo in a busy meeting room.
• Lights planned as an afterthought. The grid has to be altered and tiles get damaged when they are cut.
• Heavy equipment hung only from the grid. The runners bend and the ceiling is no longer level.

At handover, look at the ceiling from the middle of the room and also at an angle towards the window, where any unevenness shows up clearly. Go through these points:

• The grid is straight, the runners do not wave and nothing sags
• The wall angles sit tight to the wall without large gaps
• Cut tiles on opposite walls are roughly the same width
• Tiles sit flat in the grid and are not lifted or bent
• You can lift out a few tiles as a test and put them back without damage
• Heavier light fittings and equipment have their own hangers
• Tiles are clean, with no fingerprints or damaged edges
• For new electrical circuits, you have the test certificate
• You are told the exact tile type so you can buy matching ones later