Test: Estimation and Costing- 2 - Civil Engineering (CE) MCQ

Concept
Carpet area of building is the useful area or liveable area or lettable area. This is the total floor area minus the circulation area, verandahs, corridors, passages, staircase, lifts, entrance hall, etc. and minus other non-usable areas as sanitary accommodations (bath and W.Cs.), air conditioning room etc.
For office building carpet area is the useable area and for residential building carpet area is the liveable area and should exclude the kitchen, pantry, stores, and similar other room which are not used for living purposes.

The carpet area of a building for any storey shall be the floor area excluding the following:
(a) Sanitary accommodation, (b) verandahs, (c) corridors and passages, (d) kitchen and pantries, (e) stores in domestic buildings, (f) entrance hall and porches, (g) stair cases and mumties, (h) shafts for lifts, (i) barsaties, (j) garages, (k) canteens, (l) air conditioning ducts and air conditioning plant room.
The carpet area of an office building may be 60% to 75% of plinth area of the building with a target of 75%.
The planners should aim to achieve a target to 75% of the plinth area. The carpet area of residential building may be 50% to 65% of the plinth area of building with a target of 65%.

Explanation:
This is solved by using centre line method.

Total centre line length = (4 + .25) × 2 + (3 + .25) × 2 = 15 m
Height of wall = 4 m
Thickness of wall = 0.25 m.
Window area = 2 × 2 × 1.5 = 6 m²
Door area = 1.5 × 2.2 = 3.3 m²
Total opening area = where no need of brick work = 6 + 3.3 = 9.3 m²
Net effective area, where brickwork is to be done is given as:
= (Centre line length) × Height – opening area
= 15 × 4 – 9.3 = 50.7 m²
Qty of brick work = (effective area) × Thickness of wall
= 50.7 × 0.25
= 12.675 m³

Calculation:
Size of brick = 190 × 90 × 90 mm³
Let mortar thickness = 10 mm
Size of brick with mortar = 0.19 + 0.01 = 0.20, 0.09 + 0.01 = 0.1, 0.09 + 0.01 = 0.1
Volume of brick with mortar = 0.2 × 0.1 × 0.1 = 0.002 m³
No. of bricks in 1 m³ = 1/0.002 = 500 Nos.
Volume of 500 bricks without mortar = 500 × 0.19 × 0.09 × 0.09 = 0.7695 m³
Volume of mortar = 1-0.7695 = 0.2305 m³
18 % extra mortar for frog filling and wastage is considered.
So volume ofmortar = 1.18 × 0.2305 = 0.27199m³
Volume of dry mortar = 1.3 × .27199 = 0.353 m³
Percentage of dry mortar = (0.353/1) × 100 = 35.3%

Explanation:
Unit rate of items: Unit rate estimating is a method that can be used to calculate building costs. In unit rate estimating the prices of items on the bill of quantities are each calculated separately. Unit rate of items includes the contractor's profit.
Work charged establishments: It will include such temporary establishments as are employed for the execution of the immediate technical supervision or departmental stores and machinery in connection with a specific work.
Contingencies: It is an amount of money set aside to cover any unexpected costs that can arise throughout a construction project. This money is on reserve and is not allocated to any specific area of work.
Specifications: It describes the products, materials, and work required by a construction project. They do not include cost, quantity, or drawn information, and so need to be read alongside other information such as quantities, schedules, and drawings.

Explanation
The expected out-turn of a stone cutter for an item of work “ Ashlar stone dressing” is 0.70 cu m per day and for flag stone dressing, it is 1.5 cu m per day.
Out-turn of work per day per mason to some extent according to the nature, size, height, situation, location, etc. In bigger cities where specialized and experienced labour is available the out-turn is greater than small towns and country sides. 
The following may be taken as the approximate quantity of work or out turn or task for an average artisan per day.