Concrete Looks Solid—Until It Cracks

This is how buildings fail—and it’s hidden inside the concrete. #1: No concrete cover. If steel touches air or soil, rust starts and the structure weakens. Use at least 75mm cover where required. #2: A short lap splice. If bars are too short, load transfer breaks. For tension, use at least 40 times the bar diameter; for compression, 30 times. #3: Wrong spacing. Too wide hurts strength; too tight blocks concrete flow. Use the largest of 25mm, bar diameter, or 4/3 of aggregate size. You won’t see these mistakes until cracks start showing. Concrete hides it—but rebar decides everything. Follow for real construction truths.