Estimate

The term cost estimate is often used as a short form of the cost estimate , which represents a commercial preliminary calculation and is comparable to a legally binding offer.

However, the cost estimate introduced in construction is created by the client's planner (usually the architect ). The basis are the unit or flat-rate prices of the offers. Since the introduction of the HOAI in 2013 , the so-called priced specification of services has also been part of the basic services to be provided in the sixth service phase within the meaning of Section 3 (2) HOAI.

According to DIN 276 - costs in construction - the cost estimate is based on the "costs on the basis of the execution preparation". The cost estimate is to be considered in two stages, as it represents on the one hand "a basis for the decision on the implementation planning" and therefore still has to be created in the fourth service phase according to § 15 HOAI ( approval planning ). On the other hand, the cost estimate serves to “prepare for the award” and is therefore to be created in service phase 7 according to Section 15 HOAI “participation in the award”. It should be noted, however, that in the HOAI service profile in service phase 4, the cost estimate is not mentioned, but only in service phase 7.

The cost estimate is based on the planning documents, such as final, complete implementation, detail and construction drawings. To be included are z. B. Calculations for proof of stability, for thermal insulation, for sound insulation and for building services, but also service descriptions. In addition, the cost estimate is based on the offers compiled by the construction companies.

Since according to DIN 276 the cost estimate is to be provided at least up to the third level of the cost breakdown, but on the other hand it is also to be arranged according to the planned allocation units, there is usually a procedure in several steps according to the project process:

1. Step: Determining the costs according to the cost groups of the third level (components). The component- supporting outer walls of cost group 331 are cited as an example . Using the determined quantities and key cost figures (e.g. € / m³ or € / m²) from comparable projects, the costs for the new project can then be calculated. It goes without saying that the specific quality standards must be taken into account in the cost key figures. If necessary, the cost estimate must be updated if it turns out during the implementation planning that the assumptions that were made “for the decision on the implementation planning” were incorrect.
2. Step: Re-sort the costs structured according to components according to the planned allocation units. The offers can then be compared to these target costs .

Extract from ÖNORM B 1801-1 , which concerns the cost target cost estimate:

• Phase: execution phase
• Objective: budget for the award of the contract and as a cost control
• Basics: Implementation planning (preliminary draft) with information on types of use and rooms with information on quantities.
• Structure: planning-oriented - element type and execution-oriented - service position

Individual evidence

1. ↑ DIN 276-1, edition Nov. 2006, section 3.4.4 cost estimate