An expansion joint is important to allow for expansion and contraction of the given surfaces. With concrete, the expansion and contraction is common during heat. Such problems are extreme in regions like Qatar due to heat and humidity. Thus, concrete expansion joints are used to offer a buffer throughout this natural cycle. Minus quality solutions, the concrete will shift, move and crack. In extreme cases, it can result in structural damage to your house’s foundation. For more info - https://novaratsolutions.com/what-is-a-concrete-expansion-joint-and-why-is-it-important/