Estimation and Costing course lecture 1.pdf
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The document covers the fundamentals of estimating and costing in building projects, highlighting objectives of cost estimation, types of estimates, and necessary specifications. Key concepts include detailed and approximate estimates, along with processes for calculating costs and understanding the importance of proper estimation in project management. Students will learn to prepare bills of quantities, specifications, and tender documents as part of their training.
Estimation and Costing course lecture 1.pdf
- 1. Estimating and costing of building projects. Lecturer: Ahmed M Hassan (Baasaay)
- 2. Lecture 1 At the end of this lecture the learner should be able to: ➢ Objectives of Cost Estimation ➢ Define estimation ➢ State Importance of estimation ➢ Explain Data required for estimation Define Detailed estimate State types of estimates Discuss approximate estimates Compute the cost of building using approximate estimates, ( plinth area method).
- 3. Objectives - This subject covers the various aspects of estimating of quantities of items of works involved in buildings, and relative works
- 4. Objectives - This also covers the rate analysis, valuation of properties and preparation of reports for estimation of various items.
- 5. Objectives - At the end of this course the student shall be able to estimate the material quantities, prepare a bill of quantities, make specifications and prepare tender documents. Student should also be able to prepare value estimates.
- 6. Why Estimation is done? There are three things conventional wisdom says project managers must adhere (to be successful): time, Scope, and budget
- 7. DEFINITION OF ESTIMATION Estimating: is the technique of calculating or computing the various quantities and expected expenditure to be incurred on a particular work or project. Importance of estimation: ▪ Before starting any project we can know about the cost on that project. ▪ Based on this we can compare our budget with the cost require for project. ▪ We can only get benefit from project if it will complete otherwise its wastage of money.
- 8. 1.
- 12. 2. Specifications Specifications describe the nature and the class of the work, materials to be used in the work, workmanship etc. and is very important for the execution of the work. The cost of a work depends much on the specifications. Specifications should be clear.
- 13. General Specifications In general specifications, nature and class of works and names of materials that should be used are described. Only a brief description of each and every item is given. It is useful for estimating the project. The general specifications do not form a part of contract document. Detailed Specifications The detailed specifications form a part of a contract document. They specify the qualities, quantities and proportions of materials and the method of preparation and execution for a particular item of works in a project. The detailed specifications of the different items of the work are prepared separately and they describe what the work should be and how they shall be executed.
- 14. 3. Rates For estimating purpose we need (material, labour, carriage) rates. These rates should be real as per market rates. There are different government department which have their own schedule of rates. Example: (PWD, MES, FWO).
- 15. Types of estimates Types of estimates are: 1. Approximate or Rough estimate. This is an approximate estimate to find out an approximate cost of a structure before detailed estimate is prepared. 2. Detailed estimate: Is an accurate estimate of a proposed work, and it consists of the quantities, rates, and cost of each items of work. Quantities of all items of work are calculated from the specification of the drawings. A detailed estimate is accompanied by report, specification, lead statement, detailed drawings, data calculation, abstract.
- 16. 3. Revised estimate. A revised estimate is a detailed estimate for the revised quantities and rates of original estimates. 4. Supplementary Estimate. When the work is in progress, some changes or additional works are found to be necessary in a project, an additional estimate is prepared, this estimate is called supplementary. 5. Sub-Estimate In a major project consist of several small works, the estimation of sub work is called sub estimate.
- 17. 6. Annual maintenance estimate or Repair Estimate: It’s a detailed estimate to maintain the existing work and keep in good condition. Annual maintenance such as white washing, colour washing, painting, flooring etc., generally the maintenance cost in kept as 2% of capital cost of the building. - Repair Estimate: Its defined as to repair the damaged parts of a structure such as: Re-plastering the walls, change of flooring, corroded steel items, replacement of roof et.
- 18. 7. Complete Estimate: The total expenditure of a project from the beginning to the end is called complete estimate. It includes the following: Cost of land Cost of surveying Preparation of plans and estimates. Cost of approval Cost of construction Cost of electrification Cost of water supply Cost of safety devices etc.
- 19. 1. Detailed estimate The preparation of detailed estimate consist of working out quantities of various items of work and then determine the cost of each item. This is prepared in two stages: (i) Details of measurements and calculation of quantities. The complete work is divided in to various items of work such as earth work, concreting, brick work, R.c.c. plastering etc. It has the following form.
- 21. (ii) Abstract of estimated cost. In the abstract of estimate form we compute the total cost of the project. In this form the quantities of each item is from the detailed measurement form.
- 22. The detailed estimate should accompanied with: a. Report b. Specifications c. drawings ( plans, elevation, sections) d. Design charts and calculations e. standard schedule of rates Factors to be considered while preparing detailed estimate:- (i) Quantity and transportation of materials. (ii) Location of site. (iii) Labour charges
- 23. 2. Approximate estimates An approximate estimate is to find out an approximate cost of a super structure before its detailed estimate is prepared. Types of estimates 1. Plinth area method 2. Cubical content 3. Service unit method or unit cost method
- 24. 1. Plinth area method The cost of construction is determined by multiplying plinth area with plinth area rate. The area is obtained by multiplying length and breadth (outer dimensions of building). Example 1. Calculate the approximate cost of the of building of plinth area 85𝑚2 and the rate may be assumed as $800/- for civil works? Solution: Area of the building = 85𝑚2 Plinth area rate = $ 800 The approximate cost = plinth area of the building x plinth area rate. = 85𝑚2 x $800/- = $ 68,000
- 26. Calculating Area= 95.56 sq.m Total cost = $28,000 Plinth area rate = $28,000/95.56sq.m = $293/ sq.m