SSC JE Estimation AND Costing Questions with Detailed Solutions

The capacity of doing work by a skilled labour in the form of quantity of work per day is known as out tern of labour.

Given,

Book Value : The total registered cost of a property represent its book value.
=> Book value decreases with use of structure due to wear and tear or due to depreciation.
Book Value (B) = C – ND
C = Original cost of structure
D = Depreciation
N = Considered year for book value

Damp-proof course (DPC):
provided at basement levels/plinth level, which prevents moisture movement through walls and floors.
A cement concrete layer in the proportion 1: 2: 4 is generally provided at the plinth level.
The depth of the DPC varies from 4 cm to 15 cm. 
​Estimation of D.P.C work is measured in square meters of area.

The following are the common methods used to estimate buildings:
Plinth area or square meter method.
Cubic rate or cubic meter method.
Unit rate method or Service unit.
Bay method.
Cost comparison method.
Cost from materials and labour.
Approximate quantities with bill method.
Approximate quantities with bill method:
In this method, the structure is divided into:
(a) Foundation Inclusive of Plinth 
(b) The Super Structure.
The cost per running meter of the foundation inclusive of the plinth is worked out and is multiplied by the total length of the foundation to determine the total cost of the foundation inclusive of the plinth.
Similarly, the cost per running meter of the superstructure is found and is multiplied by the total length of all the walls of the superstructure to get the total cost of the superstructure.
The total cost of the structure is then obtained by the addition of total cost of foundation inclusive of plinth to the total cost of the superstructure.

Measurement Book:
The Measurement Book is the basis of all accounts of measured work and of materials received which have to be measured or counted.
It provides a complete record of works performed under a contract and will therefore include all items having a financial value, so that the final amount due under a contract may be computed.
It is also used for recording measurements of extensive services carried out by Directly Employed Workmen such as road work, pipe line laying and electric wiring.

Centre Line Method:
In this method of estimation, the total center line length of walls in a building is first calculated, then the center line length is multiplied by the breadth and depth of the respective items to get the total quantity of that item.
For rectangular, circular, and polygon (hexagonal, octagonal, etc.) buildings having no inter or cross walls, this method is quite simple.
Half the width is deducted at the junction points as it is considered twice while estimating through the centre line method.

This method is quick but requires special attention and consideration at the junctions meeting points of partition or cross walls, etc

Plinth area : Plinth area is defined as the space covered by the floor of the property, along with the area covered by its internal and external wall.
Plinth area includes : Thickness of walls but excludes the open spaces such as courtyard area, external projections like Chajas, sunshade etc.

In the execution of any work functions are performed in sequence given below :
i) Schedule of rate (SOR) :
→ SOR contains the basic rates of material, labour carriage etc.
→ It contains about more than 2500 items and finished rates of abot 3000 items of works covered under different subhead like Building Work, Concrete Work, Water Supply etc.
ii) Specifications :
→ → It is required to describe the quality of work and quantity of different materials required for construction.
iii) Estimating :
→ It is used to prepare a detailed estimate of quantities.
iv) Calling tenders : It is the process whereby a government or private organisation invites service contractors and suppliers to make an offer to executive a proposed project
v) Fixing up work agency :
→ In this steps work is assigned to an agency after tendering process.
vi) Supervision :
→ The act of watching a person or activity and making certain that everything is done correctly, safely, etc.
vii) Running will :
→ It means the bill submitted on a monthly basis for work done by the contractor
viii) The final bill for payment to the contractor :
→ It means the bill on which the final payment is made on the completion of work and is the full settlement of the account
ix) Return of earnest money deposit (EMD)

• Types of estimate :
a) Approximate estimate or preliminary estimate :
→ This estimate is prepared on the basis of practical knowledge.
→ It helps in deciding the financial aspect of the project.
→ It is required to obtain administrative approval of the project.
b) Detailed estimate :
→ In this estimate quantity of each item is worked out in the form of measurement sheet and the cost of each item is worked out in the form of an abstract sheet.
c) Revised estimate :
→ Revised estimate is done when :
• Cost of work exceeds 5% of the original sanction cost
• Cost of expenditure exceeds 10% of administrative sanction.
• When the specification of the material or method of construction changes.
d) Supplementary estimate :
→ It is required when further development is required during progress of work
or
→ It is required when addition work is required in ongoing project.

The fundamental of a building block in estimating construction labour estimate as follows :
i) Project quantities
→ It is defined as the quantity used in the project.
ii) Work hour unit rate per quantity
→ It is a method to estimate the construction cost of quantities completed in one hour.
iii) Crew mix
→ It is the combination of 72% of skilled worker and 28% of unskilled worker.
→ The size depend upon the type of project, the schedule of the project and the amount of work required to completed.
Note :
Project Owner : Project owner is a person responsible for funding the design, construction operation, and maintenance of a trade project or simple project.