A comprehensive construction cost estimation is necessary for foretelling the total cost of any structure under construction. It is an important fact to consider for cost management as well as for budget adherence. Materials and their quantity, design guideline and features, geographical area, shape, and size of the facility are some of the important variables are considered while estimating construction costs.
In most cases, construction cost estimation is done by architects, or by contractors or other specialist estimating firms. Although numerous factors are counted while creating an exhaustive development cost estimate, they ordinarily are of the following three types:
Detailed cost, Screening, primary cost and Engineer’s estimates (based on specs and architectural plans)
Cost estimate for financing and similar purposes budgeted cost after allotting to the contractor but before construction, estimated the cost of fulfillment during construction.
Negotiation or bidding by the contractor/builder/owner.
Cost of construction based on building quality
The most important factor that determines the building cost is the quality of the materials used for the construction. The types of flooring, quality of the wood chosen for windows, etc will impact heavily on the construction cost. Commonly the cost of construction based on quality is divided into 3 classes. However, the building cost is independent of the cost of furnishing and cost of purchasing land. This can be calculated according to industry standards and here also the quality.
C class: Build with low-grade bricks and sand, cheapest cement and steel, cheapest fixtures and fittings. When considered the average material cost in the industry, construction typically costs around 700 to 800 rupees per square foot of construction. When calculated in this manner, a 1000 square foot house should cost between 7 to 8 lakhs to build.
B class: Build using medium grade bricks and sand, medium cost cement and steel, medium cost fixtures and fittings. Such constructions may cost 1000 to 1100 per square foot. It’ll cost about 10 to 11 lakh to build a house of 1000 sq ft.
A class: Build using the best resources quality and class resources in the industry. This kind of building may require 1500 to 2500 rupees per square foot and hence and 1000 sq ft house may cost between 15-25 lakhs. 1500 to 2500 per square foot. On a high end, the construction cost can range from 2000 to 4000 rupees per sq ft and proportionally the build cost will also increase.
The above calculations are based on studies conducted during early 2019. The construction industry is growing and the recent changes in the economy are reflecting and impacting the cost. The cost may fluctuate geographically too. For eg, the building cost in metropolitan cities of India may differ from the suburban areas. The cost of land encompasses all expenses associated with the acquisition of the property which includes purchase prices, property taxes, preparations, and improvements.
Construction estimates can be prepared by researching the current market values for materials and labor. It can be also done by outsourcing experts or agencies. Now a lot of estimating software is available in the industry designed for contractors to estimate construction costs for any kind of project.
Types of construction estimates
There are two main types of estimating techniques in construction:
- Approximate estimates – it is a rough estimate preparing to obtain an approximate cost in the short term.
- Detailed estimates – it is preparing by determining the actual quantities and costs of everything that should be used to construct the project.
The detailed estimate is typically calculated in two ways, the unit quantity method and the total quantity method.
Unit quantity method – In this method, work is divided into multiple slots and a unit of measurement is decided. The total quantity of each item is taken out in the relevant unit of measurement. Work out the total cost per unit quantity of each item, then the total cost for the item obtained by multiplying the cost per unit quantity by the number of units. The advantage of this method is unit costs on various jobs and total estimates can be easily corrected when variations occur in quantities.
Total quantity method- In this method work will be divided into subdivisions as materials, labor, plant, overheads, and profit. The total quantities of each subdivision like the class of material or labor are found and multiplied by their individual unit cost. Similarly, all the subdivisions are determined. All the costs of subdivisions are summed up to calculate the total estimated cost of the item of work.
Data required for preparing an estimate
For preparing detailed estimate the estimator must have the following data:
- Plans for the actual dimension of the house, sections for height and other relevant details of the work
- The rate of different items
- Exact nature and classes of material to be used
Three main steps for preparing an estimate
- Taking out quantities from drawing – in this, the measurements are taken out from the drawings and entered into a measurement sheet. The measurement should be taken according to the unit of measurement described upon the measurement sheet. For example, plastering in cement mortar length and height of walls (i.e.; length*height=m2 square meter) would be needed and in the case of reinforced cement concrete for beam (i.e.; length*width*height=m3, square meter) would be entered into measurement sheet.
- Squaring out – the second step is working out volumes, area, etc. and casting up their total in the recognized units.
- Abstracting – in the last step, all the items with net results obtained in the second step are transferred from measurement sheet to specially ruled sheet multiplying the second step with the rate of each item(i.e.; length*height*rate). The second and last step known as working up.
Homebuilding cost final break down
- Land and excavation
- Size of the house
- A number of stories; this adds on to total square feet.
- Roof and other similar construction costs
- Fixtures and finishes; this depends upon the aesthetic and budgetary constraints
- House appliances; from the refrigerator to other appliances like heater, AC, etc.
- Design features; outdoor kitchens, fountains, pools the list of luxuries is pretty long depending on the design features.