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  • JM & MJ Solid Plastering

Expansion Joints and Render

Expansion joints, what are they and why are they a crucial component of a build or renovation?


Expansions joints are required on walls that exceed 6m, around windows and door frames, in between floors and when building on balconies. Though, they're not limited to these spaces only and it is important to note that different substrates have different requirements in regards to expansion joints and where they are placed. Expansion joints are fitted by the builder however for many reasons it is important that solid plasterers (also know as renderers) are familiar with the importance and specifications of these control joints as they have to be factored into your desired render finishes.


So, what is the purpose of them? Well, there are five key purposes we're going to highlight:

  • Having expansion joints allows different substrates to join with a more seamless look.

  • Expansion joints mitigate the risk of cracking in both substrates and render finishes.

  • They allow for inevitable expansion and movement within the substrates.

  • Having expansion joints reduces the stress and pressure on the substrates.

  • Building inspectors can use them as reference points and measure the gaps in the joints over time to assess movement and identify any structural issues.


When we discuss with clients the need to keep expansion joints, it's often assumed that they are not aesthetically appealing and will look terrible, but this doesn't have to be the case. There are two main ways that we will finish expansion joints, both of which are incredibly neat and allow for a seamless finish that meets standards and specifications.

When considering using render to finish your home, it's important to ensure you're using knowledgeable, qualified trades to get an immaculate finish that meets all building codes.