Difference between preliminary design, basic design and implementation design

María Eugenia Velásquez

March 21, 2022
architect drawing plans

If you are thinking of building a house, you are probably familiar with the names preliminary project, basic project and execution project, but it is also very likely that you are not entirely clear about what they are and what they are for.

If this is the case, the first thing you should be clear about is that for each project there is only one project, but this is drawn up in different phases, which are the ones I mentioned before. Read on and find out what each of these phases entails.

The pre-project: The creative phase

In this phase, the architect develops a first concept of the project that responds to the needs, tastes and preferences of the client, and that is adapted to the terrain where the work will be built - a topographical study must have been carried out beforehand.

Plans and elevations are usually presented at this stage, although mock-ups or 3D simulations can also be made so that the client can better understand the proposal.

The aim of the preliminary project is to transmit a first global idea of the work, and for this purpose it is accompanied by a written report and a budget estimate. Once the preliminary project has been approved, the basic project is launched.

The basic project: The key for the building permit

The basic project is insufficient to carry out the construction, but it is sufficient to apply for the building permit, and this is precisely its main purpose.

In this phase, the dwelling is formally described and everything to do with dimensions is justified.

The basic project includes:

- Descriptive and constructive report.

- Accreditation of compliance with the Technical Building Code, fire protection and accessibility regulations (where applicable).

- Plans and elevations.

- Budget estimate.

Once the basic project has been submitted, the process of approval of the building permit by the respective local council begins. The most common resolution period is three months, although this may vary depending on the workload of the town planning department of the corresponding town council.

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The implementation project: The guide

While awaiting the resolution of the building permit, the architect will usually continue to work on preparing the execution project.

At this stage, the degree of detail and accuracy is crucial, as the quality of the work, the reduction of unforeseen events, the accuracy of the time schedule and the budget will depend on it. In addition, the execution project must be submitted to the Architects' Association for validation (visa).

The implementation project consists of the following:

- Descriptive and constructive report of the architecture, urbanisation, installations and structure.

- Accreditation of compliance with the Technical Building Code, fire protection and accessibility regulations (where applicable).

- Calculations, performance standards, quality control plan, use and maintenance manual, safety study, waste management study, geotechnical study (if applicable) and the energy efficiency certificate must be attached to the report.

- Execution plans with all the details of the work.

- Administrative and technical conditions.

- Measurements and budget.

In this phase, in addition to the main architect of the project, technical architects and engineers are involved in order to achieve a well-designed project in accordance with the documentation and regulations in force.

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