How many sheets of plasterboard do I need for a 12m2 wall?

A standard 2.4m x 1.2m sheet covers 2.88m2. For a 12m2 wall, you would need 5 sheets plus at least 10% for waste, totaling 6 sheets.

Plaster & Plasterboard Calculator UK – Bags & Sheets Estimator

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Total Surface Area: 0.00 m²

Plasterboard Sheets (2.4x1.2m): 0 Sheets

Plaster Bags (25kg Skim): 0 Bags

Area includes walls (0m²) and deductions (0m²).

Estimated Material Cost: £0

(Based on UK trade averages for Standard board)

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UK Plastering Guide

Planning a renovation often involves "boarding and skimming." This process requires two distinct materials: Plasterboard (the base) and Finish Plaster (the smooth top layer).

Choosing the Right Plasterboard

Standard 12.5m plasterboard is the go-to for most internal walls. however, certain rooms require specialist boards:

Moisture Resistant: Essential behind showers and baths to prevent the core from rot.
Fire Rated: Required in garages, near boilers, and in some kitchen areas to slow the spread of fire.
Sound Bloc: High-density boards used in bedrooms or noisy areas to reduce sound transmission.

How Much Plaster Do I Need?

For a standard "skim coat" (the thin 2mm-3mm final finish), a 25kg bag of Thistle Multi-finish covers 10 square metres. If you are doing a "two-coat" skim (standard for most pros), you still calculate based on this 10m² rate as it accounts for the total thickness.

Note: If you are plastering over high-suction backgrounds (like old bricks or breeze blocks), you may need a "bonding" or "hardwall" base coat first, which has a much lower coverage rate.

Frequently Asked Questions

How many sheets of plasterboard do I need for a 12m² wall?

A standard 2.4m x 1.2m sheet covers 2.88m². For a 12m² wall, you would need 4.16 sheets. Always round up and add 10% for waste, so you should order 5 or 6 sheets.

How much area does a 25kg bag of plaster cover?

A standard 25kg bag of Thistle Multi-finish plaster typically covers approximately 10m² when applied at a skim thickness of 2-3mm. For bonding coats, one bag covers about 2.25m² at 11mm thickness.

Should I use 9.5mm or 12.5mm plasterboard?

12.5mm is the standard for most walls as it provides better rigidity and soundproofing. 9.5mm is often used for ceilings or for 'over-boarding' existing surfaces to reduce weight.