Structural inputs explained

Structural guidance gives preliminary member sizes to discuss with a licensed structural engineer. It is advisory only — never an approved, certified or compliant design.

Spans are clear distances between supports in metres. Imposed load is what the floor carries in use (about 1.5 kN/m² for homes, 2.5–5 kN/m² for offices and shops). Dead load is the weight of the structure and finishes.

Soil bearing capacity (kPa) comes from a site investigation; if you don't have one, the value shown is a conservative assumption and the footing sizes are rough.

Concrete grade (for example C25) is the characteristic strength in N/mm². Steel grade is the yield strength of reinforcement.