- 2073 Shrawan · 6 marks
Methods of approximate estimate
Short answer
Methods are: plinth area (similar buildings), cubic content (multi-storey), unit base (per bed/student/km), approximate quantity (plans available), typical bay (repeated units), cost of similar structure, and cost per km (roads, pipelines). Accuracy ranges 10–15%; approximate quantity is most accurate.
What are the different methods of preparing an approximate estimate? Write the suitability of each method.
| Method | How the cost is found | Suitability |
|---|---|---|
| 1. Plinth area method | Plinth area x plinth area rate of a similar building, plus extras for services | Buildings of similar type and finish; the commonest method for the preliminary estimate of offices, schools, hospitals |
| 2. Cubic content (cube rate) method | Volume of the building (plinth area x height) x rate per m³ | Multi-storey buildings, where height differs; more accurate than plinth area |
| 3. Unit base method | Cost per unit of function, such as per bed (hospital), per student (school), per seat (hall), per km (road) x number of units | Quick estimate of buildings and projects when the function is known |
| 4. Approximate quantity method | Total length of walls x rate per running metre of wall (covering the foundation and superstructure), plus roof and floor by area | Fairly accurate; used when the plan is ready but detailed drawings are not |
| 5. Typical bay method | Cost of one typical bay found in detail, multiplied by the number of bays, plus the remaining parts | Buildings with repeated bays or units, such as sheds, factories and hostels |
| 6. Cost of similar structure | The actual cost of a similar completed work, adjusted for time and place | Simple, when records of near-identical works are available |
| 7. Cost per kilometre/length | Rate per km of road, canal or pipeline | Linear projects (roads, canals, pipelines) |
The accuracy is about 10 to 15%; it is best for the approximate quantity method and least for the unit base method. The estimate must be adjusted for the location, the year and the specification.
✓ Answer checked by Claude Opus 5.5 (high effort)
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