Methods of Preparing Estimates for Cost Planning for Different Stages of RIBA Work Plan

Basically there are two cost planning methods available in the industry.

1. Elementary cost planning (Designing to cost) - Building is broken down in to various elements of functional parts.
2. Comparative cost planning (Cost to design)

Inception and feasibility Stage

Financial methods - Used to determine cost limits or the building costs in a developer's budget.

Unit method

1. No need of drawings and specifications.
2. Only the concept of the project in respect of function is required.
3. Only required historical data and the experience of the estimator in adjusting those historic data to the current figures
4. Estimate = Standard units of accommodation X Cost per unit

Scheme design Stage

Cube method

1. This method needs some of sketch drawings, purpose and function of the project.
2. Required the historical cost data and experience of the estimator is required.
3. This method is based on relationship between building volume and unit cost.
4. Estimate = volume of the building x Unit cost (cost/m³)

Superficial area method

1. Requirements are as above.
2. This   method is based on relationship between building Area and unit cost (cost/m²)
3. Estimate = Area of the building x Unit cost (cost/m²)

Story enclosure unit method

1. Requirements are as above
2. This technique use weightings for the estimating the building elements

Detail Design Stage & Production Information Stage

Elemental Cost estimating

1. Detail drawings are required
2. The method analyses the cost on an elemental basis
3. Attempting the use of cost data of similar projects

Approximate Cost estimating

1. Detail drawings are required
2. Taking  off  is  done  for  composite  items  by  grouping  together  typically  bill- measured items
3. Relates to the cost of actual work