A construction estimate is prepared in the early stages of a project before work on site begins. The process leading to a cost estimate begins with client consultation. As soon as the client lays down their building plans with an architect, he or she must take the blueprints to a quantity surveyor or professional estimator. The quantity surveyor will take off measurements from the drawings and calculate the cost of construction. The construction cost is the estimate that a client should budget for, if they intend to go ahead with the project.

Most of the times, the client has no idea of the costs until they are furnished with an estimate. In this case, according to the client’s financial standing, the cost might be too high or within their budget. When dealing with a client, the quantity surveyor’s role is producing accurate cost estimates based on the designs, and not on the client’s feelings. However, if the initial design is too expensive for the client, the quantity surveyor can advise the client to make alterations or produce an alternative design altogether. The client will be required to go back to the architect to suggest changes. Working with the client, the architect will revise the plans or produce alternative designs but this time a lot of consideration will be placed on the cost elements rather than aesthetics.

In designing a new plan, the architect must refer to the quantity surveyor’s cost estimate with the goal of identifying building elements which are taking too much cost. For example, expensive marble floor tiles may need to be replaced with low-priced ceramic tiles. One or two rooms may need to be removed and the plan configuration might need to be re-arranged or re-sized to reduce the costs. If the slate roof tiles are taking a large proportion of the cost, they might need to be replaced with a much cheaper variety or version, for example, asphalt fibreglass , clay, concrete tiles or corrugated iron/asbestos sheets.

The procedure whereby the architect designs with cost in mind is called “designing to a cost” or “designing to a budget”.  This is usually done when the client has a specific sum of money in their bank account set aside for the project. Designing to a cost will reduce the number of revisions which need to be made. To make it easier for the client, the architect may suggest building models which have been built in the past or which exist in the market. The cost of such models is known and if ever there is a fluctuation of price (building index) due to market conditions, an adjustment for price increase can be added to the known cost.

An estimate represents the actual cost of the proposed project, and a budget represents the client’s financial standing, capability or spending power. A new residential building might be estimated to be $200,000, and the client may only have $100,000 in their bank account. In this case, $200,000 or more is the required budget. A budget cannot be an estimate, but an estimate can be used for budgeting purposes and securing building finance from a lender.