Preview QSRBN prep

The examiner is testing whether you can put a number on a building that does not exist yet, and defend it. That means three things in every answer: the basis (what is included and excluded), the rate's source and date, and an explicit statement of accuracy. A candidate who writes '₦1.5bn' has answered nothing; one who writes '₦1.5bn on a gross-floor-area rate of ₦420,000/m² at 2025 price levels, excluding external works, foundations pending soil data, and within ±20% until the structural frame is designed' has produced a document a client can act on. The second thing the paper marks is arithmetic discipline: area to rate, deductions, waste, and the difference between net and gross quantities. The measurement items look simple and are where marks are lost — a candidate who bills a wall in square metres without stating its thickness, or who forgets that a floor-area rate must be multiplied by the correct area definition, has described estimating rather than done it.

The floor-area method is the workhorse at a feasibility stage: gross internal area times a rate for a building of the same type, quality and storey count, then adjustments for the things the average rate cannot know — a basement, a long span, an unusually heavy façade, site conditions that will need piling, and the services density of a laboratory or a hospital. The cubic method is better where volume drives cost (a warehouse, a car park, a hall with a high roof), because it prices the envelope that a floor rate silently assumes. Both are approximations of a cost per unit of provision, so the unit of comparison must be the same as the source data's: a rate struck for a three-storey reinforced-concrete frame in a city does not describe a single-storey steel building in a remote location. A cost plan replaces the single rate with the building's own elements — substructure, frame, roof, finishes, fittings, services, works outside the envelope, preliminaries and risk — each expressed per m² or as a percentage of the total, and it is the instrument by which a design is held to a budget. The moment it earns its keep is at concept: the plan sets a limit per element, the architect's design is measured against it, and the quantity surveyor reports the variance while there is still time to move a wall instead of deleting a window. Cost limits are meaningless without a stated allowance for what is not yet designed; and every element figure should record whether it is net of the provisional sums that sit outside it, so two people reading the plan cannot add the same money twice.