Adding a control joints or expansion gap in brickwork

LAST UPDATED: 5th January 2023 by The Editorial Team

Control joints in brickwork

Summary: Step by step guide showing how to make an expansion joint or a control joint when building a brick wall.

How to build an expansion joint

Due to the fact that brick walls can move sometimes due to both ground settlement and wall contraction and expansion, it may be necessary to insert control joints depending on the size of the stretch of wall. Over short distances, the movement of the wall is hardly noticeable or damaging, however in longer walls fractures in the structure may occur.

Adding the joint

  • To alleviate this movement, an un-mortared vertical joint should divide every 6m of wall. Although it is perfectly possible to insert these joints in a straight section of wall, it is neater and less noticeable to position them where the wall joins the pier.
  • When you do this, build the pier and the wall as normal, but exclude any mortar from the header joints of the wall.
  • Where you would normally put the wall ties, you should insert a flat, galvanised strip of 3mm thick metal in the mortar bed.
  • A good trick is to lightly smear one half of the metal strip with lubricating grease. This enables the strip to slide lengthways allowing for a certain level of movement within the brickwork, but also holding it together.
  • When you have completed all this, the gap in the wall joint on both sides can be filled with exterior sealant.

Reinforcing the piers

There is also an option of reinforcing the piers, if you feel it is necessary.

  • To do this use 16mm thick steel reinforcing rods at a height depending on the size of your pier. But make sure it is no less than 50mm from the top of the pier.
  • For taller piers, embed a rod in the concrete base, and as the work proceeds, tie extra lengths of rod to the existing one, using galvanised wire.
  • Finally, you need to fill in around the reinforcement with concrete as you build the pier, being careful not to disturb the brickwork as you go.

Tools needed

  • Sealant applicator
  • Tin snips

Materials needed

  • Galvanised strip
  • Exterior sealant
  • Reinforcement rods
  • Galvanised wire
  • Concrete

Author

The Editorial Team

The Editorial Team at lets-do-diy.com are a team of experts led by Mark Wilson. We have been creating DIY projects, articles, costs guides and product reviews since 2008. For more info see our about page.