How to cut plasterboard

Whether you're a seasoned tradesperson or trying your hand at DIY, knowing how to cut plasterboard can make any renovation easier and much more accurate. With the right tools and a bit of guidance, cutting plasterboard can be quick and mess-free.

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How much plasterboard do you need?

To work out how many boards you need:

• Multiply wall height by width = total m²
• Divide total m² by the area of one board

Example: A 5m x 10m ceiling = 50m². Divide by the size of each board to calculate how many to buy.

Jewson

What tools cut plasterboard best?

For the best way to cut plasterboard, you'll need:

Essential:

• Stanley knife
• Spirit level (or straight edge)

Optional:

• Jab saw or multitool
• Handsaw
• Rasp
• Circular saw (for large or straight cuts)

Insulation King

How to cut plasterboard

1. Mark your cut
   Use a tape measure and spirit level to draw a straight cutting line.
2. Score the surface
   Cut into the front face with a Stanley knife (around 3mm deep).
3. Snap the board
   Lift and bend the sheet backwards to break the gypsum core.
4. Cut the back lining
   Run your knife down the back paper to separate cleanly.

Tip: Use a plasterboard rasp to smooth rough edges if needed.

And there you have it, as simple as that! If you wish to smooth out the edge of your cut, you can use a rasp to do so, although this isn’t essential and is completely down to personal preference.

Jewson

How do you fit plasterboard?

1. Position boards
   Align edges with stud centres. Start at a doorway and work outwards.
2. Measure and cut
   Measure from the edge to the centre of a stud. Mark, score, and snap the board.
3. Fix in place
   Screw into studs/noggins, spacing screws 100–200mm apart.
4. Trim end boards
   Use the same score-and-snap method. Fit tightly for less filling later.
5. Around openings
   Cut boards in place using studwork as your guide. Smooth with a rasp or surform.

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How to cut plasterboard for brick walls

You can stick plasterboard directly to brick using adhesive. If walls are uneven, use timber battens first.

Dot and dab method:

• Mark adhesive spots 400mm apart
• Mix adhesive in small batches
• Apply 250mm x 50mm dabs, max 25mm thick
• Press board into place along chalk lines
• Use a timber batten to tap it flat
• Check with a spirit level before adhesive sets

Better Homes and Gardens

Can you tile directly onto plasterboard?

Yes, you can - but check the weight limits:

• Bare plasterboard holds up to 32kg/m²
• Plastered boards only 20kg/m²

To tile on plasterboard:

• Ensure it's 12.5mm thick and dry
• Dry-lay tiles to plan layout
• Apply adhesive with a notched trowel
• Cut tiles with a tile cutter or wet saw
• Grout once adhesive sets, wiping excess with a sponge

Tile4Less

Can you paint straight onto plasterboard?

Yes - just apply a mist coat first (diluted emulsion).

Before painting:

• Fill joints and screw holes
• Allow to dry completely
• Then paint or skim with plaster as preferred

Cutting plasterboard for sockets & access holes

For small holes (e.g. sockets):

• Use a jab saw or keyhole saw
• Jab into the board, then cut around the shape
• Sand or rasp the edge if needed
  
  

Extra tip: practice makes perfect

If you’re unsure how to cut plasterboard neatly, try scoring and snapping on a scrap piece first. It helps you get used to cutting deep enough into the gypsum without damaging the board.

SMART Tool Group 

How to plasterboard a ceiling and wall

Lastly, if you want to learn how to plasterboard a ceiling or a wall, see our second blog, which describes both techniques and even includes a tool list. You can find this blog by clicking here.

The Carpenter's Daughter

Still wondering how do I cut plasterboard for a specific project? Pop into your local Howarth branch or call our friendly team on 01472 907051. You can also browse our full range of plasterboard cutting tools and accessories on our plasterboard page.