EXPANSION JOINTS IN CONCRETE – WHAT YOU NEED TO KNOW
Few people think of brickwork and concrete as materials that behave like wood, expanding and contracting in different temperatures. But builders know full well that they do and that when they do there can be serious problems, unless appropriate measures, primarily the inclusion of expansion joints, have been taken.
When it comes to dealing with shifting concrete or brickwork, the experienced builder also knows that the application will dictate the factors that need to be taken into consideration, including which materials they’re going to use to create the expansion joint and what finish is required.
WHY EXPANSION JOINTS ARE IMPORTANT?
All building materials require allowance to be made for movement and flexibility, as they will expand or contract depending on climate conditions, the methods used to apply or install them, and any other materials also being used.
Concrete cracks from the forces that pass through it, potentially leading to all kinds of problems, as well as just looking terrible. Expansion joints are vital when concrete slabs are hemmed in by walls or other immovable structures, as the expanding slabs simply have nowhere to go and so exert pressure on these structures and each other. As this is the case with most indoor applications, having decent expansion joints filled with suitable material is the only way to avoid problems further down the line. Even when concrete is not adjoining walls, such as external areas of hardstanding, if the area is above a certain size (e.g. 6m in length or width) then the concrete must be laid in sections separated by movement joints.
The thermal expansion causes most of the movement in brickwork – this can be accommodated by creating an expansion joint and filling it with a foam material. On large areas of brickwork, these vertical joints are included at regular intervals, with the spacing determined by the application and type of brick or block being laid.
The material you use between these joints needs to be strong, flexible, and resistant to water ingress. Growtivation’s Siteworx range offers two types of expansion joint filler solutions for this: the Fibreboard Expansion Joint Filler is ideal for filling concrete expansion joints, while our Foam Expansion Joint Filler is perfect for using with brickwork and blockwork.
There are various rules that apply to the spacing of expansion joints, depending on whether you are using concrete, brickwork or blockwork. Additionally, when deciding where expansion joints should be placed, aesthetics and practicalities also need to be taken into consideration.
In some applications, appearance is everything. No one wants to see an ugly expansion joint in their pristine marble floor or trendy exposed brick wall. That’s why many builders recommend using an aesthetically pleasing sealant on top of fibreboard expansion joint fillers by leaving a small amount of space at the top of the boards. Siteworx Foam Expansion Joint Filler comes with a handy tear-off strip, which can be removed to create a recess for the sealant.
Le Fong’s Expansion Joint have low moisture absorption properties and, like their Foam counterpart, come in a range of sizes from long, thin strips to large boards for maximum convenience and efficiency. Expansion Joint Filler even comes in an economy or premium variety to suit different applications and budgets.