Post 313 – by Gautam Shah


An estimate is a numerical assessment of a project, done on many different scales. A primary estimate is in numbers, showing the quantity of recurrences within a specified range. Secondary estimates are in spatial quantities such as Lengths, Areas or Volumes (and weight). At third level the estimates are about ratings in time such as speed, change, movement, etc.

Spatial measures

The numbers are ranged by defining the inclusion and exclusion characteristics. These are easiest to quantify requiring no or simple tools, once the range definitions are recognised. Spatial quantities, by themselves are numbers, but each type is a range. The sub divisions and mutual relationships for conversion are comparatively simpler in ISO measure system. Ratings in time scale are mutually un-comparable.

Temporal measures

All quantity estimates, can be equated by attaching monetary values. The monetary values are derived with an exercise of costing or valuation. An estimate schedule represents a comprehensive reportage of the entire process. The estimate schedule also mentions (as a side or foot note) the rationale, means, methods of taking measurements, manipulations done with the information, and presumptions made for thinning out the data.


Format of an estimate schedule depends on for what purpose these are accessed, and by whom. A customary format is evolved by every design organization to suit its own nature of practice and needs. For commercial use like tenders or quotations etc. a style confirming to a local market is required. For Government and corporate entities, designers have to adjust the estimate schedule format to their accounting procedures requirements.

excavation estimates of very large sites (2)

Estimate reports once created are used by many different people, and for nominally never perceived uses. A person preparing the estimate must foresee that, someone else in another time span will deal with the estimate, not only to interpret, but also to revise it.

The format of presentation, logic and mode of documentation should allow easy revisions. In other words all estimates must be liquid or revisable and dynamic. This was very difficult in manual documents, but with spreadsheet-based system, every single change can be recorded and if necessary back-tracked.


Manual form of Estimate schedule


Spread sheet estimate schedule

Estimate schedules record all the contextual information and their sources. Procedures for accommodating various parameters like: fitments sizes, tolerances, mode of measurements, modules of measurements, rounding off, average, means, etc. should be of standard type, or well explained.

Accuracy of estimate on cost, quantity, repetitions, unitization, etc.

Accuracy of an estimate depends on how well the job has been conceived, categorised and detailed. Estimates that create liabilities due to their ability to cause secondary changes elsewhere (such as: item selection or elimination), or have hazardous consequences, are prepared with due care.

Budget estimates prepared, before or during the design and execution stages are approximate only, because the cost base is presumed, or of a current date. By the time actual execution occurs, the costs may go up or down, or the components may get altered. Whereas, historic estimates prepared after the item has been executed and paid for, are very exact, as the cost base is real and accomplished one.


Estimate Reports become part of finance related procedures of the client. Typically financial institutions would like to sanction a loan on things that are physical, fixed, long lasting and with resale value. As a result, soft furnishings, polishing, painting and such other expenditures are not favoured for borrowing. A designer and the client (or the financial expert) together can, to an extent, redefine some of the items, or divide and regroup the items so that these can be classified as worthy of an appropriate category of disbursement, expenditure or depreciation. By re-framing the specifications, such items can be made integral part of the hard furnishings.

Exposure of estimate reports is a very sensitive issue. Its exposure to outsiders, including the client, automatically makes it an open document with a lot of liabilities. A premature exposure conveys a hidden guarantee that items with such specifications will cost so much. A client may perceive the provisional estimate details (of a mid project appraisal, etc.) to be a promise. Where it is necessary to expose an estimate report prematurely, it should be conditional. All data, specifications, assumptions, forming the estimate base must be preserved.


Estimate reports provided to outside agencies, though prepared for their specific needs, must not create undue liability for the designer. Government and other agencies demand Estimate Reports for sanctioning grants, loans, subsidies, etc. But due to large scale design + build practice prevalent in interior design, more often than not, estimate reports are interpreted to be an advance or pro-forma-invoice for supply of goods or services, and money is accordingly issued to the author of the report (the designer), rather than to the contractor-vendor of the scheme. This could involve a designer into a huge tax liability.