Gypsum Board Ceiling and Suspended Ceiling Installation

Most systems follow a similar sequence. The details differ by manufacturer, and the installer should follow the instructions for the system being used.

1. Setting the height. A laser marks a level line on every wall where the new ceiling will sit. At the same time the installer finds the lowest point of the existing ceiling, because that decides how much height the room loses.
2. Perimeter profiles. Metal edge profiles (often labelled UD) are fixed to the walls around the room. A sealing tape usually goes behind them to reduce sound transfer and even out small bumps in the wall.
3. Hangers. Hangers are anchored into the existing ceiling: direct hangers for a small drop, adjustable ones for a larger gap. The fixings depend on what the ceiling is made of. Concrete, hollow clay blocks and timber each need a different type of plug or screw.
4. Main profiles. The carrying profiles (often labelled CD) slot into the perimeter profiles and clip onto the hangers. Their spacing usually sits around 400 to 500 mm, according to the manufacturer. This is the moment to get the whole surface perfectly level, because it cannot be corrected later.
5. Services and insulation. Before any boards go up, the electrician runs cables and fits boxes for lights, and any pipework is put in place. If mineral wool is going in for sound or heat, it goes in now.
6. Vapour control layer, only where needed. It makes sense under an unheated loft or directly under a roof, where warm moist air from the room could condense in the insulation. Between two heated floors it is usually left out. If it is used, the joints are taped airtight and sealed to the walls.
7. Boards. The boards run across the main profiles and are fixed with self-tapping drywall screws. On ceilings the screw spacing is usually around 150 to 170 mm, according to the manufacturer. The end joints of neighbouring boards are staggered so that no long continuous joint forms.
8. Jointing and sanding. The joints are reinforced with tape and filled in several coats, and the screw heads are filled too. Once dry, the surface is sanded, primed and painted.

For an ordinary flat ceiling, a board of about 12.5 mm is the usual choice. The board type depends on the room:

• Standard boards for dry rooms such as living rooms, bedrooms and hallways
• Moisture-resistant boards, often green, for bathrooms, kitchens and toilets, always together with working ventilation
• Fire-resistant boards, often red or pink, where fire resistance is required, for example under a timber loft structure or in a plant room
• Acoustic boards with perforations where you want to cut down echo in the room

Keep in mind that echo and noise from neighbours are two different problems. A perforated board improves the sound inside the room, but it does little against footsteps from the flat above. For that, flexible acoustic hangers, mineral wool and sometimes a double layer of boards help more. If noise is your main reason for the new ceiling, tell the installer before work starts.

A flat ceiling in an empty, square room with a concrete slab above is the simplest case. These things add time and effort:

• A high room that needs a scaffold tower instead of a stepladder
• An old timber or beamed ceiling where hangers are harder to anchor
• Lots of cut-outs for downlights, vent grilles or access hatches
• Insulation, a vapour control layer or a second layer of boards
• A furnished room that has to be cleared and covered
• Removing old ceiling tiles or loose plaster before the work begins
• A higher finish standard, for example where light from a window rakes across the ceiling or where gloss paint is planned

It helps a lot if you decide in advance where the lights go, where any ductwork runs and how far the ceiling is allowed to drop. Changes after the boards are up always mean more work.

A new ceiling is a good place for new wiring, but the electrical work must be done by a qualified electrician. Ideally the electrician comes in before boarding starts and, once finished, provides the certificate or test report required in your country. Cables above the ceiling should run where a screw cannot hit them.

Never hang a heavy chandelier from the plasterboard alone. It needs fixing into the original ceiling or into a timber or metal support built into the frame beforehand. Light downlights are fine, as long as their heat output and the space above them are taken into account.

A suspended ceiling inside a home rarely needs a permit, but the rules depend on local building regulations and on what else changes, for example fire separation, ventilation or the structure. Before a larger alteration, check with your local building authority. In a block of flats, let the building management or owners' association know, especially if you are fixing into a shared floor slab or touching the ventilation system.

• A sparse frame. Hangers or profiles spaced too far apart lead to sagging and cracked joints over time.
• The wrong fixings. A plug that holds firmly in concrete may not hold in hollow blocks or old timber.
• Standard board in a wet room. In a bathroom without moisture-resistant board and ventilation, mould and warping are likely.
• No movement joint. Large areas, and areas over the building's own expansion joints, need a movement joint as the manufacturer specifies, otherwise cracks appear.
• Forgotten services. Cutting holes afterwards weakens the boards and spoils the finish.
• Rushed jointing. Joints without tape or with poor sanding show through the paint, especially in side light from a window.
• Working in a cold or damp building. Boards should acclimatise in the room first, and jointing usually needs a temperature above roughly 10 °C. It should not start straight after wet plastering or screeding.

When you take over the work, bring a torch or lamp and shine it along the ceiling from the side. Small bumps show up clearly this way. Check that:

• The ceiling is flat and level, with no visible sag in the middle
• Board joints and screw heads cannot be seen in raking light
• The edges along the walls are neat and free of cracks
• Cut-outs for lights and grilles are in the agreed places and have clean edges
• Moisture-resistant boards are used in wet rooms
• Access hatches are fitted wherever valves, pipe joints or ductwork need to be reached
• The electrician has handed over the certificate for the new wiring
• You have a note of the system and board type used, for future repairs