1 ESTIMATING AND COSTING
D-III CIVIL 1.1 MEANING OF THE TERMS-
ESTIMATING, COSTING AND VALUATION
(A) An estimate can be defined as the procedure or method of working out the probable cost of a work. An estimate is prepared by working out the quantities and then calculating the cost suitable rates.
Before the construction work of any structure is started, calculation, of quantities of various items of work and its probable cost is done. This is known as estimating. Before starting any civil engineering works or project it is necessary to know its approximate cost by calculating quantity of various items and multiplying it by unit rates of materials. As far as quantity calculation part of estimating is concerned is done by studying and analysis of drawing and specification. Estimate of a work is governed by quantity and quality aspect. Quantity is related with drawings and quality is related with specification for materials and workmanship. Estimates are prepared in standard forms known as:
1. Measurement sheets. 2. Abstract sheets.
(B) Costing is defined as the determination of actual cost of the before the execution of it. To know the cost of work detail estimate is prepared and measurement sheet and the probable cost of various items entered in the abstract form.
(c) Valuation is defined as the procedure of finding out the value or fair price of a property, such as building, land, a factory, any machine, etc. By valuation present value of property is determined which may depend upon the life of property, maintenance, location, legal control. Purpose of Estimating and Costing:
Before taking up any project for execution the owner should know the total cost of the work, so that financial arrangements can be made well in advance.
From estimate the quantities of various materials required may be worked and necessary arrangements for the same can be made. The estimate also gives rough idea of the time required for completion of work.
2 The number and kind of workers of different categories required to complete the work in the specified time can be found out. An estimate is immensely useful in planning and execution of any work.
1. To know the approximate cost of work.
2. To know the approximate quantity of various materials and labors required. 3. For technical sanction of the project.
4. For inviting tenders and to arrange contract.
5. To have an idea about the time of completion of project.
6. To give an idea for keeping control over expenditure during construction. Purpose of costing
1. To determine probable cost of work before execution.
2. It helps in financial planning to owner before going for construction.
3. Costing of various items required for constriction of structures is known well in advance and accordingly arrangement of finance can be made.
4. Addition and alterations in planning and designing can be done if the costing goes beyond the capacity.
TYPES OF ESTIMATE
The following are the different types of estimate:
1. Preliminary estimate or Approximate or Abstract or Rough cost estimate 2. Plinth area estimate.
3. Cube rate estimate or Cubical content estimate. 4. Approximate quantity method estimate.
5. Detailed estimate or item rate estimate. 6. Revised estimate.
7. Supplementary estimate.
8. Supplementary and revised estimate.
3 1. Approximate Estimate:
It is required for preliminary studies of various aspects of a work or project to decide the financial position and policy for administration sanction by the competent authority like Municipal Corporation, development authority, etc.
In case of commercial projects as Irrigation, Residential buildings, and other similar projects which earn revenue income, the probable income may be worked out. From the preliminary estimate the approximate cost may be known and then income and cost is studied. If it is justified to go for project then further detailed estimates are prepared.
In case of non-commercial projects or project which does not give direct return, necessity, utility and money available can be studied.
In this type of estimate all important works like cost of land, cost of each building, cost of roads, etc. are shown separately.
Example:
1. Approximate cost of a hostel building for 100 students @ 10,000/- Rs. Per student is Rs. 10 lakhs.
2. Approximate cost of 100 bed hospital @ Rs. 50,000/- per bed comes to Rs. 50 lakhs.
The approximate estimate is prepared from the practical knowledge and cost of similar works carried out by the P.W.D. or by an Architect.
Along with the estimate, a brief report explaining the necessity and utility of the project, and showing how the cost is met with should be accompanied. A site plan also should accompany the estimate.
The preliminary estimate can be prepared by various methods for structures. (a) Buildings- service unit basis:
Each building is constructed to serve same purpose. For example, a hospital is designed to accommodate certain number of beds. Each bed is then considered as service unit of a hospital building. Whenever a building is constructed the engineer keeps the record of the place of construction actual cost of construction number of service units, etc. From this record it is possible to work out the cost of construction, number of service units, etc. From this record it is possible to work out the cost of construction per service unit.
Cost of construction per service Unit = .
4 The costs worked out by this method are very approximate and will vary considerably with buildings of different shapes and sizes, kind of construction and locality.
Example: Approximate cost of 100 bed hospital @ Rs. 30,000/- per bed comes to Rs. 30 lakhs. (b) Irrigation projects: After studying the topo sheet the dam site is marked and the catchment area is found out. Considering the total rain fall and percentage of total available yield, the capacity of reservoir is worked out. The final stage is to decide upon the cost of similar per million cubic meters of the storage with the help of records of construction costs of similar projects by P.W.D. By multiplying this cost with the total storage capacity, approximate cost is worked out.
(c) Water supply and sewerage projects: On the basis of per head of population served, approximate cost of water supply project for a population of 1 lakh people @ Rs. 80 per head works out to be Rs. 80 lakhs.
(d) For highways: Per kilometer basis, depending upon the nature of road, thickness and width of metalling, for 5 kilometers at Rs. 2 lakhs per 1 k.m., works out to Rs. 10 lakhs.
Other factors to be considered in case of approximate estimate of highway are: (i) Land to be acquired.
(ii) Width and type of wearing surface of road.
(iii) Other construction details to be provided for a particular class of road. (iv) Information about road works already constructed and the cost per kilometer. (v) Earth work.
(e) Hostel: Approximate estimate is calculated on the basis of per person. (f) Per seat in a stadium.
(g) Per seat in a stadium. (h) Per bed in a hospital. 2. Plinth Area Estimate:
This estimate is prepared on the basis of plinth of building. The rate for unit plinth area is determined from the cost of similar building having similar specifications, heights, construction and locality. Plinth area estimate is prepared by finding the plinth area of the building and multiplying by the plinth area rate.
5 Plinth area should be calculated for the covered area by taking the external dimensions of building at the floor level. This area must not include area of court yard, open passages, etc. For a multistoried building the plinth area estimate is prepared for each storey separately. Plinth area estimate is a type of approximate estimate.
Rate of construction on plinth area basis = Example:
Approximate cost of a building having plinth area of 100 sq.m. @ 900/- per sq.m. Works out as Rs. 90,000/-.
3. Cube Rate Estimate:
It is an approximate. It is prepared on the basis of cubical content of the building. The cube rate is determined from the cost of similar building having similar specification and construction in the locality. This is calculated by finding the cubical content of the building (l and
multiplying it by cube rate. It is more accurate as compared to plinth area estimate. The cubical content of building must not include foundation, plinth and parapet above roof.
Rate of construction on cube rate basis = Example:
Approximate cost of a building of cubic content (vol.) of 400 cu.m. @ 180/-Rs. Per cu.m works out as Rs. 72,000/-.
4. Approximate Quantity Method Estimate:
In this method approximate total length of walls is found in running meter (RMT) and this total length multiplied by the rate per running meter of wall. For this a structure is divided into two parts:
1. Foundation (including plinth). 2. Super structure.
The running meter cost for foundation and super structure should be calculated first and then running meter rate should be multiplied by total length of walls. For this method plan of building must be available.
1.2.1 Approximate Estimates
Approximates estimate is made to find out an approximate cost in a short time, without taking out actual quantities. This enables the responsible authority to consider the financial aspect of
6 the scheme. The accuracy of the cost estimated by such approximate estimate depends upon the judgment, skill and experience of the estimator and upon the correctness of the prices.
1.2.2 Uses
The approximate estimates are prepared to serve the following purposes:
1. To give rough idea of the probable expenditure: Before taking up any project, it is necessary to ascertain whether it can be feasible or financed. For this a rough idea of the probable expenditure has to be obtained. If this appears feasible, then further details may be obtained.
2. Administrative approval: In case of government and other public works, proper sanction has to be obtained for allocating the expenditure required for the detailed investigations and preparation of plans and estimates. This sanction is given on the basis of approximate cost found out by approximate method.
3. Valuation and rent fixation: Sometimes it is necessary to find out the cost of an existing structure
(a) Sale or purchase, (b) Rent fixation,
(c) Framing tax schedules, and (d) Insurance requirement.
In all these cases the values invariably make use of the approximate estimate. 1.2.3 Methods of Approximate Estimates
Approximate estimate is prepared to decide the financial aspect, administrative approval, for sending the proposal and appraisal of various civil engineering projects. For different type of structures like buildings, roads, bridges, railways, etc; approximate estimate is prepared from practical knowledge and cost of similar works executed in past. It shows separately cost of land, building, road, water supply, sanitary work etc.
1.2.4 Preparing Approximate Estimates for Buildings
There are four methods to find approximate estimate of building: 1. Service unit method,
2. Plinth area method, 3. Cube rate method, and
7 4. Approximate quantity method.
1. Service unit method or per unit method: Per student for hostel, per student for schools, per class room for schools, per bed for hospitals, per seat for cinema halls, per bay for factories, I,e, estimate prepared by considering the service unit of it.
Cost of construction per unit =
Such estimates are very approximates and varies according to shapes, size, type of construction and locality.
Example: Approximate cost of a 100 bed hospital @ 40,000/- Rs. Per bed works out as Rs. 40 lakhs.
2. Plinth area method: If the plan of the building is not ready or available at the beginning. Then just to prepare the proposal, floor area of rooms etc. May be determined from the requirement and 30 to 40% of the total area thus found is added for walls, circulation and waste to get the approximate total plinth area. Now plinth area is multiplied by the plinth are rate which gives approximate cost of the building. This estimate is more accurate then service unit method. Example: The building having plinth area of 100 sq.m. @ Rs. 400/- per sq. m. works out as Rs. 40,000/-.
3. Cube rate method: Rate of construction is calculated on basis of construction cost of an existing building and dividing it by volume of building. The approximate cost of building of cubic content (Vol.) of 200 cu.m. @ Rs. 150/- per cu.m. Comes to Rs. 30,000/-
4. Approximate quantity method: To find the running meter rate of foundation, the approximate qualities of items such as excavation, foundation, brick work up to plinth, D.P.C., are calculate per running meter of walls. By calculating price per running meter, rate is determined.
Similarly for super structure also the price or rate per running meter is determined for approximate quantities of brick work, wood work, roofs, floors, etc. For this method plan of building must be available.
1.2.5 Preparing Approximate Estimates for Roads and Highways
The unit to be adopted to determine approximate cost of new proposed highway is per km or per mile basis. The cost of road per km depends upon nature of road (national or state highway or village road, etc.)
Width of road, thickness of metal ling, pavement surface, temporary and permanent acquisition of land, topography and cross drainage works. Thus by knowing the cost of construction per
8 km length of a similar road, approximate estimate of proposed road can be prepared. For example state highway of 10 km is constructed in Rs. 20, 00,000/-. Therefore, approximate cost per km length is Rs. 2, 00,000/-
1.2.6 Approximate Estimate of “Railway project”
For estimate of a railway project main items or work are foundations, embankment in cutting and banking, bridges, culverts. Level and road crossing, fencing, boundary, km. post, gradient post, office building, platform, staff quarters, workshops, sanitary arrangements, etc. Railway estimates are prepared by knowing the cost per km. of recently constructed similar railway line i.e. Same gauge, sleeper, ballast, etc. while preparing approximate estimate, cost of land acquisition should also be included.
Typical Approximate Estimate
Sr. No. Particulars Qty. Rate Rs. Cost Rs.
1. Preliminary works, surveying, etc. 1km 10,000 10,000 2. Land: Permanent Temporary 1km 1km 90,000 40,000 90,000 40,000 3. Foundation 1km 1,60,000 1,60,000 4. Bridges 1km 5,50,000 5,50,000
5. Level and road crossing 1km 34,000 34,000
6 Fencing 1km 10,000 10,000
7 Boundary and gradient
posts 1km
14,000 14,000
8.
Ballast- below sleeper Main line
Siding 1km 5,00,000 5,00,000
9. Track, including laying 1km 14,000 14,000
10. Signal lines and telegraph
lines 1km 18,00,000 18,00,000 11 Station platform 1km 40,000 40,000 12 Station building - 60,000 60,000 13 Office furniture - 12,00,000 12,00,000 14 Service roads L.S. 2,50,000 2,50,000 15 Misc. L.S. 40,000 40,000 Total 48,16,000
Add for contingencies 3% 1,44,480
Add for supervision and establishment 10% 4,81,600
9 1.2.7 Preparing Approximate Estimates for Bridges and Culverts
Approximate estimate of bridges are prepared on the basis of per running meter of span or per running meter of linear water way. Approximate estimate of bridge depends upon road way, nature of bridge, depth and type of foundation, etc. Approximate cost of new proposed bridge is worked out by determining total no of spans or total length of linear water way and multiplying it by rate of construction per meter length of a recently constructed similar bridge with the similar specifications.
For culverts approximate cost may be determined per meter of span. Per meter of linear water way or per no of culvert of different span. Approximate cost of bridge and culvert can also be worked out according to sub-structure and super structure respectively. For example approximate cost of bridge having 3 spans of 50 meter each, comes out to be Rs. 25,00,000/- at a rate of Rs. 20,000/- per running meter of span.
In short, approximate estimate of a bridge can be calculated as below: 1. Find linear water ways during the time of floods.
2. The known cost of construction of a similar bridge is divided by its linear water ways to find out the rate of construction per meter of linear water ways.
3. Multiply this total linear water ways at the site with the rate of construction per meter of linear water ways. It will be the approximate cost of bridge.
By dividing the bridge in two parts i.e. sub-structure and super-structure, approximate cost can be found out separately.
1.2.8 Preparing Approximate Estimates for Irrigation Projects
Approximate estimate of irrigation project is determined by considering approximate estimate of storage reservoir, dam and canals. For storage reservoir and dam, estimate is prepared on the basis of per million cubic meters of storage capacity or per sq. mt. of catchment area. For canals, per km basis or per cubic meter capacity of canal or per hectare of commanded area, approximate estimate is prepared.
Examples:
1. Approximate cost of 10 km long irrigation canal is Rs. 10 lakhs at a rate of Rs. 1, 00,000/- per km.
2. For an irrigation project of commanded area 2000 hectares approximate estimate is Rs. 80lakhs at a rate of Rs. 4,000/- per hectare.
10 1.2.9 Preparing Approximate Estimates for Water supply
The basis of preparing approximate estimate of water supply project is the population to be served by this project. Thus, by knowing cost of water supply works per capita from similar project already executed approximate cost of a new project can be worked out. Sometimes approximate estimate for this project is also prepared on the basis of area covered i.e. per hectare basis.
For example approximate cost of water supply project for a population of 70,000 at a rate of Rs. 120/- precipitin comes out to be Rs. 84,00,000/-
For overhead water tank: On the basis of capacity, per litre (gallon) of tank depending on the type of structure, height of tank etc.
Approximate cost of an overhead R.C.C. water tank of 50,000 litre capacity @ Rs. 9 per litre works out to Rs. 4.5 lakh.
Preparation of estimate includes the following:
1. Data collection: Situation or location, configuration, rain fall, population, existing water supply, existing drainage system, necessity of scheme, etc.
2. Estimation of cost of project: (a) Preliminary survey.
(b) Head works.
(c) Well and pump house, (d) Inspection well, (e) Pumping machineries, (f) Rising main,
(g) G.S.R. (Ground storage Reservoir), (h) Treatment works,
(i) E.S.R. (Elevated Service Reservoir), (j) Distribution system,
(k) Approach roads, (l) Staff quarters, and
11 (m) Land acquisition.
1.2.10 Preparing Approximate Estimates for Drainage
Approximate estimate of sewerage project is prepared on the basis of per head of population to be served by taking help of rates per capita from a similar sanitary project already executed or on the basis of area covered by drainage lines i.e. per hectare basis.
Example: Approximate cost of a sewerage project for population of 50,000 souls comes to Rs. 60 lakhs at a rate of Rs. 120/- per head.
1.2.11 Preparing Approximate Estimates for Storage Reservoirs and Dams
Per million cubic meter of storage capacity: This is a quick method of estimating cost of a scheme without carrying out any survey or preparation of drawings. The method consists of following steps:
1. Selection of suitable site with the help of topo-sheets. 2. Find the catchment area.
3. Find rain fall data from rain gauge station near catchment area. 4. Capacity of reservoir by contours.
5. Decide construction cost per million cu.m. Of storage.
6. By multiplying this cost with the total storage capacity, approximate cost is worked out. 1.3 DEAILED ESTIMATES
It is an accurate estimate and consists of working out the quantities of each item of work and working out the cost. The dimension, length breadth and height of each item are taken out correctly from drawing and quantities of each item are determined. Then abstracting and billing is done.
A detailed estimate is prepared in two stages:
1. Details of measurement and calculation of quantities. 2. Abstract of estimated cost.
Details of measurements of each item of work are taken from plan and drawings and calculated in measurement sheet.
Abstract is prepared by determining cost of each item of work. The rates of different items are taken from schedule of rates.
12 1.3.1 Types of Detailed Estimate
There are various types of detailed estimates which are prepared under various conditions of construction of a new or old work. There estimate give accurate amount of items and cost required for it. Various types are as below:
(1) Revised estimate. (2) Supplementary estimate
(3) Revised and supplementary estimate etc. 1.3.2 Detailed Estimate of a New Work
While preparing detailed estimate of a new work various steps are required to be followed by an estimator, like knowing the various items to be executed, study of drawings, study of specifications and rates of various items.
For a new work all the items must be described in measurement sheet using specifications and their quantities of work shall be calculated according to dimensions given in drawing.
For example if you want to prepare all estimate of a new road, various items will be, clearing the site, construction of sub grade , sub base, base course, wearing coat, mile stone, arboriculture culverts if any, etc.
For example detailed estimate of a new residential building will include various items as below. (1) Clearing the site, removing bushes, leveling the plot etc. and complete.
(2) Excavation of foundation below ground and leveling the trenches dug with compacting, watering and termite proofing if any, etc. and complete.
(3) P.C.C. bedding below foundation in C.M. (1:6), 250 mm thick with proper mixing and compacting, curing etc. and complete.
(4) U.C.R. masonry in C.M. (1:5) in plinth and foundation with laying, curing etc. and complete.
(5) B.B. M in C.M. (1:6) in super structure with lying bricks, checking line and levels laying mort ant and curing etc. and complete. On the similar guidelines detailed estimate of a new work can be prepared.
1.3.3 Revised Estimate
13 1. When the original sanction estimate exceeded more than 5%.
2. When the expenditure of a work exceeds or likely to exceed the amount of administrative sanction by more than 10%.
(3) When there are material deviations from the original proposal, even though the cost may be met from the sanctioned amount
1.3.4 Supplementary Estimate
It is a detailed estimate and is prepared when works are required to supplement the original works. When further development is required during the progress of work, a fresh detailed estimate is prepared for additional work. The supplementary amount is shown separately in the abstract along with original amount, for sanction.
1.3.5 Supplementary and Revised Estimate
When the work is practically abandoned and estimated cost of remaining work is less than 95% of the original work, or less than 90% of the original sanctioned estimate or when there is material deviation and changes in design is there. Then the amount of original estimate is revised by the competent authority. A supplementary and revised estimate is prepared and fresh technical sanction of the competent authority is obtained.
1.3.6 Maintenance and Repair Estimate
This is a detailed estimate and it is prepared to maintain the structure or work proper order and in safe condition.
For buildings, this includes white washing, colour washing, painting and minor repairs etc For road work, this includes patch work, renewals, repairs of bridges and vulverts.
For annual repair of building 1 to 1.5% of the original construction cost of the whole building is provided.
These estimates may be on the basis of time of repairs like quadrennial repair estimates, special repair estimates etc.
1.3.7 Uses of Detailed Estimate
Detailed estimate is prepared for technical sanction of the project by competent authority, for arranging contract and for execution of work.
14 Ex.1: Prepare an approximate estimate of a residential building of plinth area 1000 m2. If the cost of construction of a building with similar specification in locality is Rs. 1,62,00000/- for 1800m2 of construction.
Solution:
Plinth area rate = =
= Rs. 9,000/-per m2 Approximate cost of new residential building = plinth area
= 1000 9000
= Rs. 9000000/-
Ex. 2: A hospital building of 150 beds is constructed in Talegaon in the cost of construction of Rs. 25 lacs. Find the approximate estimate of a small hospital of 35 beds in the similar locality by using service unit method.
Solution:
Rate per service unit = =
Rs. 16666.66 per bed.
∴ Approximate cost of newly proposed hospital of 35 beds
= Number of beds Rate per bed
= 35 16666.66
= Rs. 583333.33
Ex. 3: The cost of construction of a college building in Vasai is 1 crores 40 lacs for a capacity of 400 students and cover area of construction about 1800m2. Prepare approximate estimate of a newly proposed college building of 1235 students with the area 7000 m2. Use service unit method and plinth area method.
15 (i) Service unit method:
Rate of construction per student basis =
= !
!
= Rs. 35000/-per student
∴ Approximate estimate of new proposed college
= Number of student Rate per student
= 1235 35000
= 43225000/-
= 4 crores, 32 lacs and 25 thousands. (ii) Plinth area method:
Rate per m2 of plinth area = " = !
= Rs. 7777.77 per sq.m.
∴ Approximate estimate of new college of 7000m2 = 7777.77 7000
= Rs. 54444444.44
Ex. 4: A residential building of g+4 has been constructed in pune and having a plinth area of 200 m2. Height of building is 16.5 m above ground. The cost of construction of the building is 8000000/- (eighty lacs). Using method of cube rates estimate prepare an estimate of a building of 12 m height and area at plinth 290 m2. It has four floors.
Solution:
Rate of construction on cube rate basis = = "#! = $ # . % = Rs. 2424.84 per m3
16 = 2425/-
Approximate estimate of new building = Rate/ m3 Volume of new building
= 2425
= 2425 290 12
= 84, 39000/-
∴ Approximate estimate = Eight four lacs, thirty nine thousands only.
2.1 METHODS OF DETAILED ESTIMATE
Detailed estimate of work can be prepared by using following methods: 2.1.1 Unit Quantity Method
This estimate can be prepared quick and easily but it requires record of unit quantity rates for similar structures, in same locality with similar specifications. Various departments can maintain unit cost of those works. Other than unit quantity rates following points are considered, (1) Price level variations, (2) specification required, (3) Location of site, (4) Number of units in structure and (5) Foundation and soil conditions etc. This method is used for preparing preliminary estimates.
2.1.2 Total Quantity Method
In this method, with the help of detailed drawing total quantity of various items is calculated. Items can be obtained by dividing the whole structure into different components.
Now this total quantity of each item is multiplied with the unit rate of respective item, which can be obtained either from schedule of rates or from analysis of that item. This given as estimated cost of that item. On adding amount required for all items we get estimate of whole project. 2.1.3 Data Required For Estimate
Following data are necessary for preparing an estimate:
1. Drawing: A detailed drawing showing plan, elevation and section with all the dimensions is essential.
2. Specifications: Specification gives description of materials to be used, mode of execution quality of work etc. The rates of items depend on specification.
3. Rates: The market rates of various items, wages of different categories of labour, cost of different materials should be made available.
17 4. Mode of measurement:
The units which are commonly used are: (i) for length metre (ii) for area –sq. meter (iii) for volume cubic meter (iv) for capacity-litre (v) for mass –kg.
For voluminous works- the length, breadth and height are measured and volume is calculated. The unit of measurement is cubic metre.
For long and thin works only the length is measured and unit of measurement is running metre. Statement showing the unit of measurement of different items used in civil engineering works is given below:
Units of Measurement: m3, m2, running meter, kg, quintal, tone etc. 1. Earth work m3
2. P.C.C. m3 3. R.C.C. m3 4. Brick work m3 5. Stone masonry m3
6. Wood work for door and window frames m3
7. Door and window shutters m2 8. Cement concrete grill work m2 9. 10 cm thick brick wall m2 10. D.P.C. m2 11. Plastering and pointing m2 12. Flooring m2
13. Skirting m2 (for 1 tile), RMT (for
tile) 14. Grills and collapsible gate m2
15. Tiled roofing, A.C. sheets, G.I. sheets m2 16. Centering and shuttering or form work m2
18 17. Dado m2
18. Oil paint/colouring m2 19. Barbed wire fencing RMT 20. Railing RMT 21. Pipe RMT 22. Brick on edge Numbers 23. W.C. pan/wash basin Numbers 24. Manhole cover Numbers 25. Site clearance Job (Lump sum) 26. Electric wiring Point
27. M.S. Reinforcement Kg or Metric Tonne (M. Ton) 28. Timbering of trenches m2
29. Grouting for crack joints m2 30. Surface drying m2 5. Abstract from I.S. 1200:
I.S. 1200: The I.S. deals with the method of measurement of buildings and civil engineering works. This Indian standard was adopted by India Standard Institution after the draft finalized by Civil works Measurement sectional Committee and is approved by the civil Engineering Division Council.
Measurement has a very important place in the planning and execution of any civil engineering work from the time of estimate to final completion and settlement of payment to the contractors. There are 25 parts in I.S. 1200, each one being published separately. They deal with method of measurement for earth work, brick, stone work, etc. These I.S. codes give rules for rounding off the numerical values; successive rounding number of figures and general rules for measurement of works.
The I.S. 1200 guides in preparing the estimates, taking measurements of works and making payments to contractors.
19 (a) Openings upto 0.1m2 in section.
(b) Ends of beams, lintels, rafters, purlins up to 0.05m2 in section.
(c) Wall plates and bed plates, bearing of slabs and chajjas where the thickness does not exceed 10cm and the bearing does not exend over the full width of wall. From the gross volume of masonry all other openings are deducted.
Rules for making Deductions in Plastering and Painting Work:
(a) No deductions are made for openings not exceeding 0.5 m2 each and no additions are made
for jambs, soffits and sills of these openings.
(b) For openings more than 0.5m2 but not exceeding 3 m2, 50% of opening area should be deducted for one face only. No additions are made for jambs, soffits and sills.
(c) For openings more than 3 m2, full opening area should be deducted for one face only. Separate additions made of jambs, soffits and sills.
Rules for painting work: Painting of doors shall be measured closed and flat in m2. It shall include frames, edges, cleats etc. Different types of doors and windows shall be grouped under one item and they are of uneven surface shall be converted into equivalent area. The multiplying factors for different doors surface are given below:
Particulars Multiplying factor
1. Panelled, ledged, battened and framed 2. Fully glazed
3. Partly paneled and partly glazed 4. Flush door
5. Louvered door 6. For corrugated sheet 7. Iron bars, grill work
1 (for one side)
(for one side) 1 (for one side) 1 (for one side)
1 (for one side ) 1.20 (for one side)
(for one side)
2.1.4 Factors to be considered during preparation of Detailed Estimate
1. The nature of work: When a construction work is divided in different items of work such as ear work, concrete, brick work, etc. The quantity of items is carefully calculated. If nature of work is large the transportation charges, availability of material and labour should be kept in mind. If nature of work is then use of local materials and labour available should be done. 2. Quantity and availability of material: If quantity of material required is in large amount the concept of bulk purchasing in whole sale should be used, while deciding rates of items.
20 3. Transportation of materials: If materials required for project is not available locally the transportation charges should be added to each item while preparing detailed estimate.
4. Location of site: If site is in the remote area or away from city then transportation charges should be include while costing. If site is not approachable then cutting of jungles, construction of pilot road. Arrangement of electricity, transfer of machinery etc. requires a large cost.
5. Labour charges: For preparing detail estimate, local labor charges should be known to estimate. These charges should be revised from time to time depending on locality before preparing detailed estimate
2.1.5 Specification
Specification is a statement of particulars for execution of any item of work, its specification must known. Specifications are written by experts of a particular field. In this chapter; necessity, purpose methods of writing specifications and its types are explained in detail, usig suitable example.
Necessity and Importance of Specifications: (A) Necessity:
A specification is a statement of particulars. An engineering specification contains detailed description of all workmanship and materials which are required to complete an engineering project in accordance with drawing details. The drawings show the proportions and relative positions of the various components of the structure. It is not possible to furnish the information on the drawings regarding the quality of materials to be used and the quality of workmanship to be achieved during construction, due to shortage of space. Thus details regarding materials and workmanship are conveyed in a separate contract document which is known as the specifications of the work. In general, the drawings showed what is to be done, whereas the specifications state how it is to be accomplished.
It is understood that the combination of the drawings and specifications will define completely the physical, technical and operating characteristics of the finished project.
(B) Importance of Specifications:
The conditions of contract often include a statement describing the procedure to be followed in the event of conflict between drawings and specifications:
(a) In the event of conflict within drawings the large-scale details shall govern the small scale details.
(b) In the event of conflict between the specifications and drawings, the specifications shall govern drawing.
21 (c) Purpose of Specifications:
The structural drawings show the shape and size of the various structural components. It is not possible to give details regarding the quality of materials and the workmanship of each and every items of the work on the drawing itself. The quality of the material and the workmanship or methods of completing the works etc. In detail are furnished in separate document, know as specifications. The specifications are generally written to supplement information shown on drawings. They serve the following purposes:
1. To give the required information for an item of work which cannot be shown on the plan? 2. To help the contractor in giving the necessary quotation for work.
3. For necessary execution of the work, for supervising.
Points to be observed in framing the Specifications of an Item: (A) Method of Writing Specifications:
The specifications are prepared by Engineer or Architect. While writing the specifications, it is not known who will be the contractor. Therefore, while writing the specifications, care is taken that it should be clearly understood by the supervisors, workmen, contractors, etc. Some of the requirements are stated below:
1. Simple and clear language should be used. Rules of grammar should be adhered to. The wordings should give clear meaning.
2. The specifications should be brief. Long sentences should be avoided.
3. The specifications should be fair to all parties. Practical limitations of materials and workmanship should be kept in view.
4. When old or standard specifications are used for the preparation of new set, care should be taken to delete inapplicable material.
5. As the specifications are the legal documents, they should be concise as far as possible, because of fewer words will involve less risk or legal difficulties.
(B) Specification paragraph:
The paragraph of a particular specification should be arranged in the following sequences: 1. Materials that is required for work.
2. Specifications for materials.
22 4. Procedure for executive the work.
5. Tests, if any.
6. Clearing on completion. 7. Mode of measurements.
(C) Legal Aspects of Specifications:
Specifications form a part of contract document, without which the contract document becomes invalid on each page of the specifications both the parties i.e., owner and contractor should sign so that these specifications, where clear instructions, regarding the quality and procedure of works etc., are given will be binding on both the parties.
If any dispute arises between the parties, the specifications will help the arbitrator or the court to settle the dispute. If the contractor’s work deviates from the specifications, he will be liable for penalty.
The specification also mentions the mode of measurements, quality and procedure of item. So, it is binding on both the parties to adhere to it. The contractor cannot ask for extra measurements or owner cannot give less measurements.
The general character and the scope of the work in illustrated and defined by the specifications and signed by both parties. So it becomes a legal binding on both the parties to adhere strictly to the agree specifications.
In the absence of complete specification, the contractor’s obligation is limited to performance of only what is called for in such incomplete specifications. As such great care has to be taken in preparing specifications.
Types of Specifications:
The specifications can be broadly classified as:
1. Contract specifications: The specifications written for a particular construction project given contract to accompany the detailed drawings are called contract specifications or project specifications. These are further divided into two groups:
(a) General specifications. (b) Particular specifications.
2. Guide specifications: These are prepared to serve as guidelines for preparing project specifications
23 3. Standard specifications: Usually, the specifications are standardized for most of works, by the departments. These standard specifications are numbered. After standardizing specifications, it is not necessary to write detailed specifications, with all the contract documents. While preparing the contract document only the serial number of standard specifications is written. This saves time, labor and other expenditures.
For example, the Bureau of Indian Standard has prepared volumes of specifications for a wide variely of materials. These standard specifications are also revised from time to include changes in technique while preparing the contract document.
4. Manufacture’s Specifications: Manufactures of building materials or product, publish specifications of their products. These are in the form of standard specifications or Guide specifications.
5. General specifications: General specifications give the nature and type of materials which are to be used in the different items of works. In other words, it is the brief description of various items of work, specifying the materials, qualities, proportions, etc. These give the idea about the whole work, therefore, it is known as general specifications.
6. Detailed specifications: The detailed specifications describe the item of work in details, accurately and complete in all respects in relation to the drawings of the works.
The detailed specifications of an item of work specify the quality and quantities of materials, the proportion of mortar, workmanship, and the method of preparation, execution and mode of measurements. The detailed specifications are arranged in the same sequence of order as the work carried out. The detailed specifications form an important part of contract document.
Every Engineering Department prepares the detailed specifications of the various items of works and get them printed in a book form known as ‘Detailed Specifications’. When the work is taken up, instead of writing the specifications every time, the printed detailed specifications are referred.
2.1.6 Quantity and Availability of Material
While detailed estimate is prepared for any work an estimator must think of quantity of material required for an item and its availability. If a material mentioned in specifications of a work, for an item is not available in market in the required quantity, then the estimator shall take the help of department. He shall discuss the matter with the tender inviting authority and decision can be taken.
Sometimes materials required are not available within a reasonable distance from the site of work, and it is required to be transported from a long distance. Then the provision shall be made in the estimate mentioning the place of availability of material required for an item of work. If
24 the quantity of material required is in large amount than concept of bulk purchasing shall be used.
2.1.7 Location of Site
This is a very important which are suppose to mentioned in the detailed estimate and while abstracting the quantities of items of work, it shall be taken into account.
If the site is in remote areas or away from town. Then rates of items shall be taken in abstract sheet by considering location of site. If this point is ignored while preparing the estimate than the cost of detailed estimate will be less than the actual costing of work and that will lead to difficulties to the owner or department as for as finance is concern. If site is not approachable easily then cutting of jungles construction of pilot roads, arrangement of electricity requires huge cost, so that shall be included in abstract sheet.
2.1.8 Labour Component
For every item of work an estimator shall think various factors while abstracting the quantities of work.
(i) Quantity of material (ii) Location of site
(iii) Type of labour required (iv) Costing of labour
(v) Special skilled labour required etc.
Labour component in the costing plays a very important role because it covers about 30% to 40% of cost of an item. If labour component is not taken in to consideration while preparing detailed estimate than the estimated cost calculated will be less than the actual cost required for a work. A provision of contingencies and work charged establishment shall also be made in an estimate which can compensate any deficiency in an estimate.
2.2 STEPS IN PREPARING DETAILED ESTIMATES Step NO. 1: Divide the whole project or work in various items.
Step No. 2: Divide the various items and group them under different sub heads.
Stpe No. 3: Enter the detailed of measurement of each item of work in measurements form and calculate the total quantity of each.
25 Step No. 4: After the quantities are taken out squaring the dimensions is done. It means the calculation of number, length, are and volumes are entered in last two columns of measurements sheet. There are various methods of squaring the dimensions: (1) Decimal system, (2) Duo-decimal system and (3) Fractional part and practice.
Now-a-days decimal system is used. All these squared dimensions must be checked by different persons by tick-mark in other colour ink. If any correction is done it must be cross- checked. Step No.5: This is the last step in preparing detailed estimate. The cost under item of work is calculated from the quantities computed at workable rates. These costs along with rates are entered in ‘Abstract Form’. In abstracting 3 to 5% amount of total cost is added for contingencies such as petty expenditure, unforeseen expenditure, changes in design, changes in rates, etc;
which may occur during the execution. A percentage of 1భ
మ to 2% of total cost is added for the
expenditure of work charge establishment. The grand total gives the estimated cost of work.
2.2.1 Main Items of work for Detailed Estimate and their Units Main items of work are given below in case of buildings, roads, etc.
1. Earthwork: Earthwork in excavation and in filling should be taken out separately under different types. Foundation trenches are usually dug to the exact width of foundation with vertical sides. Quantity of earthwork is calculated by taking dimensions length, width and height. Earthwork is measured in cubic meter.
2. Bed concrete in foundation: It is calculated by taking length, breadth and thickness of concrete bed; measured in cubic meter.
3. Soiling: When the soil is soft, one layer of brick or stone is laid below the bed concrete. It is in square meter and expressed with specified thickness.
4. D.P. C. (Damp proof course): It is a course provided at the plinth level under the wall for te full width of plinth wall. It is not provided at the sill of door and verandah openings for which deduction is made which calculating length of D.P.C. it is measured in square meter and
expressed with specified thickness. In general 2.5 cm thick cement concrete (1:1
:3) with water proofing materials is used as O.P.C.
5. Masonry: Masonry for foundation and plinth is taken under one item and masonry for super tracture is taken under separate item. It is computed in cubic meter by taking length, breadth and height. In case of wall footing, masonry for steps is calculated separately and added together. iN buildings having more one floor, the masonry for superstructure for each floor is computed separately. Deductions for openings like doors, windows, cupboards, etc. is done.
26 Decution for lintels for openings is also done by taking length, breadth and height. Different types of masonry are taken under separate items. Thin partition walls of thickness less than 10 cm, honeycomb brickwork is taken under separate item in square meter and no deduction for holes is done.
6. Lintel: Lintel are casted in R.C.C. and quantity is calculated in cubic meter. Length of lintel is equal to size of opening plus of 150 mm each on both sides.
7. R.C.C. : R.C.C. Work is calculated for beams, lintels, columns, footing, slabs etc. It is calculated cubic meter, by taking length, breadth and thickness. No deduction for steel is done while calculating the quantity of concrete, which includes centering, shuttering and fixing of reinforcement in position. Reinforcement (quantity of steel) is taken under separate item, including bending and measured in kg, quintals, or in metric tone. If detail drawings are not available 0.8 to 3% of concrete may be taken by volumes as a quantity of steel which is further multiplied by density.
Centering and shuttering are usually included in R.C.C. but may also be taken separately in square meter of surface in contact with concrete. In R.C.C. Work, plastering is not taken separately.
8. Flooring: For grounds floor, cement concrete and floor finishing of stone, marble or mosaic tiles taken under one item and quantity is calculated in square meter. For upper floors, bed of R.C.C. is taken cubic meter and other member is calculated in cubic meter.
9. Roof: In Case of roof, flat roofs are calculated in cubic meter like slab and for pitched roof. Quantity of trusses and other members is calculated in cubic meter.
In case of roofing material tiles, G.I. sheets or A.C. sheets are measured in square meter. Tiles on hip and valley are measured running meter.
10. Plastering and pointing: Plastering is calculated in square meter and expressed with specified thickness. For masonry the measurements are taken for whole face of wall for both sides as solid and deduction for openings are made.
External and internal plastering for building are taken out separately, under different times. Pointing of walls is calculated in square meter for whole surface and deductions are made similar to plastering.
11. Doors and Windows: It consists of frame and shutter. Doors and windows framers are calculated in cubic meter. Quantity is obtained by calculating length including jamb, head and sill and multiplied by cross-section of frame.
Doors and window shutters are calculated in square meter. Shutter of different types should be taken separately because the rates differ. Hold-fast are taken as a separate item.
27 12. Painting and Varnishing: Painting and varnishing of doors and windows are calculated in square meter. The area measured for this purpose is flat.
13. White washing or distempering: The quantities are taken in square meter. The inside is white wash or distemper and this item is same as internal plaster. Outside is colour wash and its quantity is same external plaster. These items need not be calculated separately and simply written as same for internal and external plaster.
14. Electrification: Generally 8% of estimated cost of building works is taken for this item. 15. Sanitary and water supply works: Generally 8% of estimated cost of building works is taken for this item.
2.2.2 I.S. Method of Taking out Quantities (Introduction only) This method includes following process:
1. Taking off; 2. Grouping; 3. Billing.
In taking off and grouping details of various items along with their quantities are calculated and entered in measurement sheet in their sequential order of execution. The process of building is done on the abstract sheet in the same sequence of items as appeared in measurement sheet. This method is easy and requires less time.
2.2.3 Squaring
Squaring is the process while preparing the detailed estimate of a work in which the quantities calculated as per drawing and specification are rounding off the numerical values as per the guide lines IS 1200.
After the quantities are taken out, squaring is done. It means the calculation of number, length, area volumes are in last two columns of standard measurement sheet. There are various methods of squaring. The dimensions
(i) Decimal system (ii) Duo-decimal system
28 Now a day decimal system is used in which quantities are rounded off to next complete number. Squared dimensions must be checked by different person by tick mark in other colour ink, and if an correction is found, it should be cross checked.
2.2.4 Abstracting
This is the last step of preparation of detailed estimate. The cost of an item is calculated from the quantities entered in measurement sheet and rates. There costs, along with rates, are entered in Abstract sheet. This process is known as abstracting while abstracting 3 to 5% amount of total cost is added for contingencies such as expenditure. While abstracting, 2% of the total cost in the estimate for the provision of work charged establishment.
While abstracting 8 to 10% of total cost is added for plumbing, sanitary and electrical installation in case of estimate of a building.
Following rules are following while abstracting the quantities: (i) Description of item shall be written in short.
(ii) Item number shall be same as appeared in measurement sheet. (iii) Rates of items shall be written in rupees with per unit etc. (iv) Total amount of each page should be carried forward. SOLVED EXAMPLES
Ex. 1: Fig 2.1 represents plan and section of a trench which is 90 cm wide and 100 cm deep. Calculate the quantity of earth work in excavation by using:
1. Long wall and short wall method 2. Centre line method.
Solution:
1. Long wall and short wall method: m wide is short wall.
Length of long wall for an item = Centre = ( = 4.5m
Length of short wall for an item = Centre line length of short wall = (3.5 = 1.7m Details of measurements: Item No. Description of item No. 1. Earth work in excavation : Long walls Short walls 1 2 2
2. Centre line method:
Total length of centre line from the plan = [(4.5-0.45
= 12.4m No of junctions = 0
method: Let us assume that 4.5 m side in plan is long wall and 3.5
= Centre line length of long wall + width of item
= (4.5-0.45 +0.9
= 4.5m
Length of short wall for an item = Centre line length of short wall – Width of item = (3.5-0.45 2) – 0.9m = 1.7m No. L B H Qty. 4.5m 1.7m 0.9 0.9 1.0 1.0 8.1m3 3.06
Total length of centre line from the plan
29 Let us assume that 4.5 m side in plan is long wall and 3.5
of item Width of item Total Qty. Remark 11.16m3
∴ Deduction from length = 0 Item No. Description of item No. 1. Earth work in excavation: 1
Ex.2: Fig. 2.2 shows the plan of a
Estimal the quantities of (1) Earth work in excavation in foundation, (2) Lime concrete bed in foundation and (3) U.C.R. masonry in foundation and plinth by using long wall and short wall method any by using centre line method.
Solution:
1. Long wall and short wall method:
Let us assume 5.0 m side is long wall and 4 m side is short wall. No. of long walls= 2, No. of short walls =2
Length of long walls for an item = Centre line length of long wa
Length of short walls for an item = Centre line length of short wall + width of item
No. L B H Qty.
12.4 0.9 1 11.16
Fig. 2.2 shows the plan of a single room building with section of foundation wall. Estimal the quantities of (1) Earth work in excavation in foundation, (2) Lime concrete bed in foundation and (3) U.C.R. masonry in foundation and plinth by using long wall and
y using centre line method.
1. Long wall and short wall method:
Let us assume 5.0 m side is long wall and 4 m side is short wall. No. of long walls= 2, No. of
Length of long walls for an item = Centre line length of long wall+ Width of item Length of short walls for an item = Centre line length of short wall + width of item
30 Total
Qty.
Remark 11.16m3
single room building with section of foundation wall. Estimal the quantities of (1) Earth work in excavation in foundation, (2) Lime concrete bed in foundation and (3) U.C.R. masonry in foundation and plinth by using long wall and
Let us assume 5.0 m side is long wall and 4 m side is short wall. No. of long walls= 2, No. of
ll+ Width of item Length of short walls for an item = Centre line length of short wall + width of item
2. Central line method:
Total length of centre line = [(5+0.15 = 19.2m
Number of junctions with cross walls = 0 Deduction from length = 0
Total length of centre line = [(5+0.15
s walls = 0
Details of measurements: Item No. Description of item 1. 2. 3. Earth work in excavation foundation Lime concrete in foundation U.C.R. in foundation and plinth Step 1 Step 2 Step 3
Ex: Calculate the quantities of the following items in case of a shown in the drawing given:
1. Earth work in excavation.
2. Cement concrete (1:2:4) in foundation. 3. 1st class brick work in cement mortar (1:3) 4. 2.5 cm thick artificial stone flooring
5 16 mm thick cement plaster (1:3) on floor and walls.
6. 12 mm thick cement plaster (1:3) on top of wall and external plastering.
Solution:
1. Centre line method:
No. L B H Qty, Earth work in foundation Lime concrete in U.C.R. in foundation 1 1 1 1 1 19.2 19.2 19.2 19.2 19.2 0.9 0.9 0.6 0.5 0.4 1.3 0.2 0.3 0.8 0.6 22.464 3.456 3.456 7.68 4.608
alculate the quantities of the following items in case of a underground water
2. Cement concrete (1:2:4) in foundation. class brick work in cement mortar (1:3)
stone flooring.
mm thick cement plaster (1:3) on floor and walls.
aster (1:3) on top of wall and external plastering.
32 Qty, Total Qty.
22.464 3.456 3.456 7.68 4.608 22.464m3 3.456m3 15.744m3
Total length of centre line for 40 cm thick Total length of centre line for 30 cm thick
Total length of centre line for 20 cm thick
Details of measurement:
Total length of centre line for 40 cm thick wall = (5.4 +3.9) = 18.6m
centre line for 30 cm thick wall = (5.3+3.8) 2 = 18.2m
Total length of centre line for 20 cm thick wall = (5.2+3.7)
= 17.8m
Ex. 4: Fig 2.4 shows the plan and cross
Prepare an estimate with the quantities of the following items: 1. Earth work in excavation in foundation.
2. P.C.C. bed in foundation (
3. U.C.R. Masonry for foundation and plinth. 4. 2.5 cm cement concrete D.P.C.
5. Brick work in super structure in C.M. (1:6), 6. Plinth filling materials.
Total length of centre lines on the plan = 4.4 Number of junctions = 2
Deduction from length = Details of measurement:
Ex. 4: Fig 2.4 shows the plan and cross section of wall of a building with Prepare an estimate with the quantities of the following items:
1. Earth work in excavation in foundation. 2. P.C.C. bed in foundation (1:2:4).
3. U.C.R. Masonry for foundation and plinth. 4. 2.5 cm cement concrete D.P.C.
5. Brick work in super structure in C.M. (1:6), . Plinth filling materials.
of centre lines on the plan = 4.4 = 33.8m
34 building with two rooms.
36 2.3 PREPARING CHECK LIST
1. It should be checked that all the items required for execution of a work are included in the estimate.
2. All the items must be described with general specifications to guide while entering the rates in abstracting.
3. Length of various items should be calculated carefully by observing the drawings by suitable method.
4. Rules of Tead and lift deduction additions, multiplying factors should be followed according to I.S. 1200.
5. Total quantity of an item must be expressed with its unit of measurement.
6. While abstracting item number and total quantity of items they should be taken from measurement sheet and after preparing the estimate it should be cross checked.
7. Rates of various items should be taken from D.S.R. (District schedule of Rates).
8. Total amount in abstract sheet should be calculated on every page at the bottom and carried forward on the top of next page.
9. According to the nature of work provision of contingencies as 5% of estimated cost, provision work charge establishment as 2% of estimated cost, provision of electrification (if required) as 8% of estimated cost and provision of water supply and sanitary works as 8% of estimated cost should be added the total at the end of abstracts.
2.3.1 Sequence of Execution
It is an art of breaking up the work into various items of work and arranging them in the order of their execution. While sequence of execution of items of work, knowledge of that particular work whose estimate is to be prepared, shall be used.
The sequence of taking out the quantities of items is same as the sequence of execution.
For example sequence of items to be executed for a building is clearing the site, excavation, P.C.C. U.C.R. in foundation and plinth or R.C.C. footing, beams, columns, slabs, brick work in super structure pluming, electrification (concealed), plastering, painting etc.
37 2.3.2
Brief Specification of items
General Specifications of a First class Building:
Foundation and plinth: Foundation and plinth shall be of first class brickwork in lime mortar (or cement mortar) over lime concrete (or 1:4:8 cement concrete).
Damp proof course: D.P.C. shall be of 2 cm thick cement mortar 1:2or 2.5 cm thick cement concrete 1:
:3, with 3
% composeal or 5% pudlo, by weight or other standard water proofing
materials as specified.
Superstructure: Superstructure shall be of first class brickwork with lime mortar or 1:6 cement mortar
Roofing: Roof shall be RCC slab with an insulation layer and lime concrete terracing above, supporte over R.S. joists or R.C.C. beams as required. Height of the rooms shall not be less than 4 m (12’).
Flooring: Drawing room and dining room floors shall be of mosaic. Bathroom and W.C. floors and dado shall be of mosaic. Floors of bedrooms shall be coloured and polished of 2.5 cm cement concrete over 7.5 cm lime concrete. Floors of others shall be of 2.5 cm cement concrete over 7.5 cm line concrete, polished.
Finishing: Inside and outside shall be of 13 mm cement plastered 1:6, Drawing, dining and bedrooms, inside shall be distempered and others, inside white washed 3 coats. Outside shall be color washed two coats over one coat of white wash.
Doors and windows: Frames shall be of well seasoned teak wood. Shutters shall be teak wood 4.5 cm thick paneled, glazed or partly paneled and partly giazed as required with additional wire gauge shutters. All fittings shall be of brass. Doors and windows shall be varnished or painted with high class enamel paint. Windows shall be provided with iron gratings.
Miscellaneous: Rainwater pipe of cast iron or of asbestos cement shall be provided and finished painted. Building shall be provided with first class sanitary and water fittings and electrical installations. 1m to 1.5 wide apron shall be provide all round the building.
General Specifications of a second class Building:
Foundation and Plinth: Foundation and plinth shall be of first class brickwork with lime mortar over lime concrete.
38 Damp proof course: DPC shall be or 2 cm thick cement mortar 1:2 with 3
% composeal of 5%
pudlo by weight of cement or other standard water proofing materials.
Superstructure: The superstructure shall be of second class brickwork in mud mortar except usual trimming as joints sills, etc. which shall be of second class brickwork in lime mortar. Roofing: Roof shall be flat terraced roof supported over wooden battens and beams of jack arch roof, or R.B. roof. Verandah roof may be of A.C. sheet or Allahabad tiles.
Flooring: Floors shall be of 2.5 cm cement mortar plastered and outside cement mortar plaster with painting. Ceiling shall be plastered in C:M 1:3. Inside shall be while washed in 3 coats. Outside should be colour washed in 2 coats over our coat of white wash.
Doors and windows: Frames shall be of well seasoned teakwood and shutters of sal, deodar or shisham wood 4 cm thick, paneled or glazed as required. They should be fitted with iron fittings and painted in 2 coats.
Miscellaneous: Rain water pipes shall be of cast iron. Electrification, sanitary and water fitting can be provided as per the requirements.
Detailed Specifications of Various Items of Work: (A) P.C.C. 1:4:8 for Foundation Concrete:
1. General: Ordinary Portland cement shall be used. The cement shall conform to I.S. 269- 1958. Cement remaining in store for more than 60 days from the date of receipt from the factory shall be subjected to tests and used only if found satisfactory.
2. Coarse aggregate Shall be of hard broken stone of granite or similar stone, free from dust and other organic materials. The stone ballast shall be of 40 mm size and well graded, so that the voids do not exceed 42 per cent.
3. Fine aggregate shall be of coarse sand, consisting of hard, sharp and angular grains and shall pass through screen of 4.75mm square mesh. Sand shall be of standard specifications, clean and free from dust dirt and organic matters.
4. Water shall be clean, from alkaline and acid matters and only potable water shall be used. 5. Proportion: The proportion of concrete shall be 1:4:8, as cement: sand: ballast, by volume unless otherwise specified.
Stone aggregate and sand shall be measured by box. One bag of cement should be considered
1/30 cu. m. Size of measured box may be 30 cm 30 38 35 28 equivalen to