What is the typical minimum thickness for reinforcing bars in slabs at 400 mm centers?

The typical minimum thickness for reinforcing bars in slabs at 400 mm centers is 6 mm (1/4 inch). This measurement represents a standard that ensures adequate strength and durability in concrete applications. The use of reinforcing bars (rebar) helps to resist tensile forces, which concrete alone cannot withstand effectively.

Using a minimum thickness of 6 mm strikes a balance between providing enough strength to accommodate loads while also being manageable to work with during installation. This thickness is commonly specified in construction codes and industry standards to promote safety and structural integrity in concrete slabs.

While other thicknesses may be used in specific applications or under certain conditions, the 6 mm standard is widely accepted for general use in standard slab construction at the specified reinforcement spacing. This is why it represents the correct answer for typical practices in carpentry and concrete work.