An expansion joint is a thin gap built into brickwork which allows for slight movement which may naturally occur (from seasonal heat changes or foundation settlement etc.).
There are a couple of sub categories of Expansion joints including control joints, and articulation joints. Each a slightly more specific definition, but generally follow the same principle of allowing small amounts of movement in materials.
Expansion joints in Australian residential buildings are typically filled with a pre-moulded foam strip or neoprene pad. A Licensed builder who takes pride in his work will typically try to colour match the expansion joint with the brickwork. It is important that the material used in the expansion joint is weatherproof; most expansion joints will require a special flexible sealant for adequate weather proofing.
The purpose of an expansion joint is to allow for small amounts of expansion and contraction to avoid cracking or more significant damage to brick walls or concrete slabs.
Fun pub trivia fact!
Did you know that clay products will expand overtime while cement based products will shrink overtime? This is important in building design; as a mixture of the 2 could cause nasty issues if not accounted for!
Expansion Joint Defects
Some of the more common defects we find during building and pest inspections, relating to expansion joints include:
- Expansion joints missing entirely.
- Expansion joints which have been placed, but in the wrong positions can still allow cracking to occur.
- Expansion joints are missing the expansion foam filler and not sealed. This will allow moisture penetration straight into the brickwork.
Which expansion joint has been completed correctly?
Have a guess then hover over the images below to find out which is right!
Click here to find out why.
The image highlighted green is the expansion joint found during a building and pest inspection in Newcastle which has been completed appropriately. This is because it has been adequately weatherproofed using a suitable flexible sealant. This means that this expansion joint will mitigate the risk of moisture penetration while also allowing for adequate expansion and contraction of the brickwork.