Preliminary estimates, also called theoretical estimates, are made during the design and planning phase of a construction project. There are many estimation methods, some of which are outdated and some of which are highly recommended and used by today’s quantity surveyors. Below is a list of estimates that surveyors can make based on the information available. Of all these estimates, the elemental estimate and estimate quantities are highly recommended, but if you don’t have enough information to make these estimates, you should start with basic estimate types such as shallow.
Target area and unit method:
Suggested methods:
· Unit method
· Surface level area method
· Basic estimates
· Approximate amount
· Note Highly recommended
Obsolete methods:
· The cube method
· Ground fixing method
· Surface measurement method
· Proposed cost estimate
Unitary method. This bid estimation is done at an early stage when design plans are not available. The estimator can work with the data to some extent based on the number of personal units required by the client.
Number of individual units x cost per unit = total cost of the building
These personal units come in different forms. They can be:
· Number of building occupants
· Number of rooms or bedrooms in a building
· Number of desks in the classroom
· Number of bellboys or beds in a hotel
· Number of beds in a hospital
· Number of parking cells in an underground parking lot
· Number of cows in the dairy farm facility
· The number of beds in a prison.
· Number of tables in a restaurant
· Number of stalls in a market
· A number of seats in a movie theater or movie theater building.
Soil surface method. Once the sketch designs with floor areas are available, the estimator can measure the total floor area of the interior of the building and multiply it by the construction cost of the same MP2. Based on data provided by local municipalities, building societies, real estate developers, and consulting surveyors, the construction cost per square meter varies depending on the area, location, and type of building.
Total floor area inside building x cost per m2 = total building cost
Elemental estimate: this estimate requires more information than the target areas. To use this method, you need to draw with enough information such as wall height, structural frame, roof structure, ceilings, foundation cross-section, floor construction, exterior work, finishes of the walls and floor. The document contains detailed information on building elements. A project can have 21 building elements depending on the specifications and capacity. To calculate the total cost, the quantity surveyor must price components that are grouped based on similar areas or lengths. An estimation guide with measurement rules must be followed.
Total building cost = total cost of all building elements
Estimated Amount – This estimate requires advanced drawing as enough information is required to increase the composite rates. This is a quick way to generate non-standard quantities, although it is not really a BOQ but a preliminary estimate. In this method, the quantity monitor groups the items related to the invoice amount into groups that can be quickly measured using a group unit of measure. An integral rate is created for each group, and therefore this estimate takes a long time to develop compared to other methods, although it is a more reliable estimate. The total cost of a project is calculated by adding a subset of the groups.
Estimated Amount – This estimate requires advanced drawing as enough information is required to increase the composite rates. This is a quick way to generate non-standard quantities, although it is not really a BOQ but a preliminary estimate. In this method, the quantity monitor groups the items related to the invoice amount into groups that can be quickly measured using a group unit of measure. An integral rate is created for each group, and therefore this estimate takes a long time to develop compared to other methods, although it is a more reliable estimate. The total cost of a project is calculated by adding a subset of the groups
