Guess, size, replace, confirm: how beam self-weight enters a takedown, the junction double-count that biases frames, and why the skeleton is 15-30 percent.
Slab self-weight is thickness times density. Reinforced concrete is about 25 kN per cubic metre, so a 150 mm slab weighs about 3.75 kN per square metre. Here is how to get it right.
A wall's line load is its weight per metre of length: height times thickness times unit weight. Here is the method, typical material weights, and a worked example.