Plasterboard liner grammage explained: how to choose between 140 and 220 g/m²

Plasterboard manufacturing is a deceptively delicate process. A modern gypsum board line runs at 80 to 120 metres per minute, sandwiching a slurry of stucco between two paper liners that must arrive with predictable strength, porosity and surface chemistry. The liner is not packaging — it is structural. Choosing the wrong grammage costs throughput, increases waste and accelerates wear on the forming station.

Face liner vs back liner: two different jobs

The face liner is the visible side: it receives the joint compound, paint or wallpaper. It must be smooth, sized for paintability, and resistant to fibre lift. The back liner is hidden but carries the structural tension load during handling, scoring and snapping. Mills typically specify face liners at 140–170 g/m² and back liners at 180–220 g/m², though regional norms vary.

The five variables that actually matter

• Grammage (g/m²) — the headline number, but never the only one.
• Fibre composition — 100% recycled mixed waste vs blends with virgin kraft change tensile and porosity.
• Bonding strength — slurry-to-paper adhesion drives edge integrity at the snap line.
• Cobb value — surface water absorption controls how quickly the stucco grabs the liner.
• Air permeability — determines water vapour escape during the dryer pass.

Why over-specifying is as expensive as under-specifying

Plant managers sometimes default to the heaviest liner they can run, assuming it is the safe choice. It is not. Heavier paper increases roll diameter (shorter changeover cycles), raises dryer energy demand, and slows the forming pickup. We typically see a 3–5% throughput penalty for every 20 g/m² of unnecessary face liner, plus a measurable rise in scrap at the cut-off saw.

"Specify the lightest liner that survives your worst handling case — not the heaviest one your line can swallow."

How WeePaper helps you specify

We sample mill-direct liners across the 140–220 g/m² range with full COA: tensile MD/CD, Cobb 60, porosity, brightness and ISEGA where applicable. We benchmark against your current grade and propose two alternatives — one cost-optimised, one performance-optimised — with landed price to your plant.