Building Estimate In Excel – Importance, Preparation

What is an Estimate?

An estimate is the expected or probable work cost and is generally prepared before the construction’s execution.

For the construction of all engineering works, it is essential to know the probable cost of construction for the complete work previously that including labour cost, material cost, transportation cost, scaffolding cost, tools and plants cost, water cost, taxes, charges for supervision and establishment and contractor’s profit.

If the above estimated probable cost is higher than the available fund, exercises are performed to reduce the cost by changing the specifications or reducing the work.

For preparing an estimate, the quantities of several work items are determined by straightforward mensuration systems, and from these quantities, the cost is computed.

The calculations mainly consist of (length x breadth x height) or ( length x breadth) or ( height/thickness).

Hence an estimator has to go into details of each item, whether big or small by imagining a building or structure, etc. from the study of drawing and specifications.

Accuracy in the estimate is essential; otherwise, it is difficult to arrange for additional money if the expenditure exceeds the estimate.

The rate of each item should be reasonable and preferably the present market rate.

Importance of Estimating

1. An estimate helps to determine the approximate cost of works before their execution; thus, we can know whether the work can be completed according to given specifications within a specific budget. 
2. It is needed to invite tenders for the work and to prepare a contract for the project.
3. An estimate helps to check the work performed by contractors during and after execution. The contractor’s payment is also made as per the present measurements by examining the already made calculations for each work item.
4. It provides an idea for the necessities of controlled materials like cement, steel, brick, etc. 
5.  A complete estimate helps to advise the client on the following.

• Properties Valuation based on land and building for purchase, sale, mortgage, etc.
• Standard rent Fixation 
• On a cover note regarding fire insurance
• The sale price of flats in case of the building being constructed on an ownership basis.
• On an arbitration proceeding to claim the reasonable amount of building.

Data Needed for the preparation of an estimate

Drawing

Fully complete dimensioned drawings, i.e., plan, sectional elevation, section, and other details.

Specifications

The detailed specification provides work nature, quality and class, materials to be used in different parts of work, material quality and proportion, preparation method, workmanship, and work’s execution description.

Rates

The rates of the different work items, construction materials, and the labour wages of various categories (skilled or unskilled) should be available for making an estimate. 

Sanctioned SOR (Schedule of rates) should be followed, or the rate may be calculated by the rates analysis method.

After collecting the above information, the estimate is then worked out under various sub-heads of work, and the quantities/cost under each sub-head are then worked out.

Factors to be viewed for the preparation of a detailed estimate

The following factors should be examined while preparing the detailed estimate.

Quantity of materials

For large works, many materials are required; the same can be purchased at a cheaper than the rate of a smaller quantity of materials.

So the rate should be framed according to the volume of the work.

Availability of the materials

The estimated cost of work will be higher if the materials required are not available as and when required, the workers and supervisory will remain idle due to this.

It will also affect the work progress. So it should be assumed that the materials required for the execution of work should be available at the worksite as and when required.

Transportation of materials

The cost of transportation of smaller quantities of materials will be more than the cost of transportation of a large number of materials bought at a time.

Location of site

Suppose the worksite is located at an old place where frequent loading and unloading are necessary several times.

Due to different modes of transport, damage or loss of materials should be considered carefully.

Availability of labour

Daily wages of local labour should be considered before the preparation of an estimate, as for as possible local available labour should be engaged.

Also, Read - House Construction Cost Calculator Excel Sheet

Procedure For Building Estimation

Drawing Interpretations

Before Calculating the quantities of different items, you must read the drawing thoroughly and correctly.

1. The dimension of each room
2. Schedule of openings
3. Work Specification
4. Wall Thickness
5. Foundation Type and its details
6. Stair Details

Prepare Quantity Sheet or Building Estimate Format

The sample quantity sheet for estimation is as follows.

Calculation Of Quantity of Different Items

Now you have to calculate the quantities of different items from their length, width and height/depth. By multiplying length x breadth x height you will get the quantity in cubic meters (If dimensions are in meters) and by multiplying ( length x breadth) or ( height/thickness) you will get the quantity in Square meters ( If dimensions are in meter).

Important Points

1. Depth for excavation is considered from the bottom of PCC to ground level.
2. Trench size is considered greater than footing size due to working space for labours. Here in the above quantity sheet footing size is 1meter × 1 meter and we have considered 0.3 meters extra for the working area.

How to get the Building estimate Excel Sheet?

To get the building estimation quantity sheet, please mail “I want estimation excel sheet” to [email protected].

Also, Read

Estimate of Building Work – Long Wall Short Wall Method, Centre Line Method

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How to Calculate Quantity of Steel In One Way Slab

How to Calculate Cement, Sand and Aggregate Quantity in Concrete