How many plaster tiles do I need for a suspended ceiling?

Before breaking out the existing ceiling, you have to decide between two solutions that are calculated differently and give very different results: prefabricated plaster tiles or a continuous plasterboard suspended ceiling.

Plaster: prefabricated 60×60 tiles

For plaster ceilings, 60×60 cm tiles are used, each covering 0.36 m². An 8% waste allowance is added for cuts at the edges.

Worked example: for a 15 m² ceiling: (15 ÷ 0.36) × 1.08 = 46 tiles of 60×60 to buy. This is the same calculation the PresupuestoYa calculator applies automatically for the Bricklayer trade.

For ceilings with electrical or plumbing services above, always leave enough space between the slab and the suspended ceiling before deciding the drop.

Plasterboard: continuous finish with no visible joints

The plasterboard suspended ceiling uses plasterboard on a metal framework, with a smooth finish and no visible joints after skimming. A 10% margin for offcuts is added to the area.

There are two framing systems:

• Direct (anchored to the slab): cheaper and lowers the ceiling less.
• Continuous (with channels and hangers): allows a greater drop and hides bulky services better, but costs more and takes longer to install.

Insulation: mineral wool or polystyrene

In the suspended ceiling cavity a mineral wool or polystyrene panel is fitted to improve thermal and acoustic insulation, with a 5% purchase margin:

• Mineral wool: better acoustic performance, absorbs airborne noise.
• Polystyrene: insulates better thermally and doesn't absorb moisture.

For ceilings under a roof or over noisy premises, mineral wool is usually the best option.

Don't forget the access hatch

Before closing the suspended ceiling, always think about where the stopcocks, shutter motors or junction boxes end up: it's much cheaper to provide an access hatch now than to open the ceiling later to reach a point that got covered over.

Frequently asked questions

How many plaster tiles do I need for 20 m² of ceiling? (20 ÷ 0.36) × 1.08 ≈ 61 tiles of 60×60.

When is continuous plasterboard worth it over plaster tiles? When a finish with no visible joints is wanted, or when bulky services must be hidden with continuous framing that allows a greater drop.

What insulation do I choose if the ceiling is under a very noisy area? Mineral wool: it absorbs airborne noise better than polystyrene, although the latter insulates slightly better thermally.

Conclusion

Choosing between prefabricated plaster and continuous plasterboard depends on the finish wanted and how much has to be hidden above the ceiling, not just on the starting price. Providing the access hatch before closing up is the detail that saves having to reopen the ceiling months later.