Question 1

How do I calculate how many plasterboard sheets I need?

Accepted Answer

Calculate the total area of your walls and ceilings. Subtract the area of any doors and windows. Divide the net area by the area of one board. Round up and add your wastage allowance (typically 10%). This calculator does all of this automatically - add each wall or ceiling area, deduct openings and it shows your board count instantly.

Question 2

What is the most common plasterboard sheet size in the UK?

Accepted Answer

The most widely available size in UK builders merchants is 2400mm × 1200mm (approximately 8ft × 4ft), which covers 2.88 m² per board. Other common sizes include 2400×900mm for easier solo handling and 1800×900mm for lower ceilings or tight spaces.

Question 3

What thickness plasterboard should I use?

Accepted Answer

12.5mm is the standard thickness for most walls and ceilings in UK homes. 9.5mm (sometimes called ceiling grade) is lighter and used where weight is a concern, particularly for ceilings. 15mm is used in acoustic, fire-resistant or high-load situations. Always check building regulations for fire-rated or moisture-resistant requirements in your specific application.

Question 4

How much wastage should I allow for plasterboard?

Accepted Answer

10% is a typical planning allowance for straightforward rectangular rooms. For rooms with lots of windows, doors, internal corners or unusual shapes, 15% is more appropriate. Cuts around electrical sockets, window reveals and doorways add up. Buying slightly over is much cheaper than a second trip or delivery charge.

Question 5

Do I need special plasterboard for bathrooms?

Accepted Answer

Yes - moisture-resistant plasterboard (often green or blue in colour) should be used in bathrooms, shower rooms, kitchens and other wet areas. Standard plasterboard is not suitable for areas that will be regularly exposed to steam or moisture. Check building regulations for your specific application.

Question 6

Should I board walls horizontally or vertically?

Accepted Answer

Both approaches are used. Vertical boarding (long edge parallel to studs) uses boards of standard width and is common for lower ceilings. Horizontal boarding can reduce the number of vertical joints and gives better rigidity on stud frames, which is why many professional plasterers prefer it. Either can give good results - the choice depends on ceiling height, stud spacing and personal preference.

Size	Area per board	Typical use
2400×1200mm (standard)	2.88 m²	Most common - walls and ceilings
2400×900mm	2.16 m²	Easier solo handling
1800×900mm	1.62 m²	Short walls, awkward spaces
3000×1200mm	3.60 m²	Taller rooms, fewer joints

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Plasterboard sheet sizes - UK guide

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