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Breaking a BOQ into zones

Muthari guides · for contractors who fabricate what they install

To track execution against a bill of quantities, break every line into zones. A zone is one label and one quantity, and the sum of a line's zones is the line's quantity. The label is whatever the site calls the place — an elevation and level range for a façade, a room for joinery, a grid line for steel. The quantity is in the BOQ unit. That is the whole model, and its power is in its strictness: every stage stamp, delivery note, installation entry and inspection then has an address, and installed quantity can be compared with contract quantity zone by zone. Two rules keep it honest. Zones cannot add up to more than the line without triggering a variation. And once the breakdown is in use it is frozen — changes are recorded, never edited.

Choosing the zone size

Too coarse and there is nothing to track: one zone per BOQ line tells you the line is "in progress" for nine months. Too fine and nobody will stamp it: a zone per panel means four hundred stamps a week and a floor that stops recording by Thursday. The working rule is that a zone is the amount of work one crew can finish and one inspection visit can cover. For a curtain wall that is typically an elevation across two to four levels; for joinery it is a room or a suite; for steel it is a grid bay or a lift of columns.

One label, one quantity

"Tower B · East · L12–L15 · 240 m²" is a zone. "Tower B east side, various" is not, because nothing can be counted against it. If a label needs the word "various" or "etc.", split it.

Rooms, elevations and grids as zones

The over-contract freeze

When the zones of a line add up to more than the contract quantity, something has changed — a remeasure, a design growth, a client instruction — and it is a variation, not a typo. The right behaviour is to freeze the breakdown at that moment, record the excess as a variation for approval, and only then let execution proceed on the extra quantity. Installing the excess first and arguing later is how specialist contractors install work for free.

The practice

How Muthari OS handles this. BOQ items carry reference, description, quantity, rate and their zone breakdown, and can be imported from a spreadsheet. A zone is one label and one quantity, exactly as above. When zone totals exceed the line, the breakdown freezes and a quantity-excess variation is created for the approval ladder, with the audit of who approved it; an approved remeasure — positive or, as an omission, negative — revises the claimable quantity on the record. Every production stage, delivery note, installation entry and inspection is keyed to the zone; installation entries are additive and cannot exceed the zone quantity. Honest limit: there are no separate building, elevation or floor fields — the label convention you choose is the hierarchy, so choose it on day one.

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