Why do plasterboard walls need expansion joints?

Why do plasterboard walls need expansion joints?

Expansion joints are designed to relieve stress and reduce the risk of cracking in lining board materials used in walls and ceilings.
Key Points:

• Most effective way to stop cracked plasterboard
• Control expansion and contraction with discrete, clean finish
• Studco® now offers three different expansion control joints

Read time: 2 mins

All buildings are prone to experience some movement due to thermal and moisture variations in the atmosphere. Expansion joints can efficiently absorb expansion and contraction in walls and ceilings to mitigate the risk of cracked plasterboard.

Studco now manufactures three different types of expansion control joints for plasterboard linings:

EJ10 Expansion Joint - Studco AU
EJ06-30 – For use on plasterboard linings of up to 6mm thick. Allows for maximum 2mm movement in any direction.
EJ10-30 – For use on plasterboard linings up to 13mm thick. Allows for maximum 2mm movement in any direction.
EJ35-30 – NEW! For use on plasterboard linings up to 16mm thick. Allows for maximum 5mm movement in any direction.

The EJ35-30 is a premium control joint for set bead finish on internal plasterboard walls and ceilings. It uses a highly flexible PVC element that allows for 5mm movement in all three directions. The EJ35-30 is supplied pre-assembled, ready to install, with a removable tape to protect the exposed PVC element which allows for easy clean-up after plastering and painting is completed. Cutting to length on-site is easy with a pair of tin snips.

Studco’s new EJ35-30 complies with all plasterboard manufacturers requirements and provides a strong, straight finish with a discrete and clean finish. For installation intervals, please refer to manufacturer’s recommendations and NCC requirements.

Studco EJ35-30 expansion joint specifications:

  • Designed to relieve stress from building movement
  • Suitable for plasterboard walls and ceilings
  • Galvanised steel set beads for flush finish
  • Integrated hi-flex PVC element, white in colour
  • Internal use only


  • Neat and clean for architectural finish
  • Allows for +/-5mm movement in all directions
  • Supplied pre-assembled, ready to install
  • Fast, easy clean up after installation
  • Easy to cut to length
  • Complies with plasterboard manufacturers requirements

Studco Expansion Joints

Studco EJ35 expansion joints installed in plasterboard ceiling prior to trowelling in.
Where two different lining boards meet, the Studco EJ35 expansion control joint is the perfect partner.
When finished and painted, the Studco EJ35 expansion joint is discrete and unobtrusive.
Plasterboard control joints installed where a long corridor changes direction.


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