Performing Construction Quantity Survey
Updated: Oct 18, 2021
A construction QS is about measuring items on drawings to identify how many resources (material, labor, and equipment) are needed to complete a job.
Why QSs Are Necessary for Construction Projects?
Generating extremely accurate construction estimates for construction work is crucial for success. A rough estimate leaves with extra material to pay for them, which could result in cash flow.
Who Is Responsible for Completing a Construction QS?
In large construction contraction companies, often a billing and tendering department shares responsibility for QS and progress invoicing compilations.
In smaller companies, until it’s feasible to hire more staff, the owner or a single estimator will handle all QSs, but this practice is unsustainable for the long term if the business aims for substantial growth.
When there are material QSs, which involve performing measurements and applying formulas to determine how much material is needed. Most trades also perform material QSs. Some examples include measuring:
Running meter for installing tile skirting, window sills, electrical cables, etc.
Surface area (square meter) for installing flooring, application of plaster, paints, or pouring concrete grade slabs.
Volume (cubic meter) for civil and site work such as excavation or pouring concrete slabs or walls.
Quantity survey results in the exact amount of materials needed for construction.
Material QSs require assigning items and assemblies to measurements so that it can calculate quantities based on how materials are packaged,e.g for 1 cum of concrete, you would need 7 bags of concrete, 1200 Kgs of coarse aggregates, 800 kg of fine aggregates, 125 lts of water.
The Real Purpose of a QS in Construction
The most common mistakes that happen in the QS process come down to missing deadlines and inaccurate measurements which leads to improper invoicing.
The QS is just one part of the preconstruction process, leading up to creating an estimate and proposal. The objective of performing QSs is to create a clear picture of the cost of materials needed for a construction job. It aims to determine non-material costs, like labor hours, overhead, equipment requirements, and other indirect costs.
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