Question 1

What are the SIA phases in architecture?

Accepted Answer

The SIA phases describe the official process of a construction project in Switzerland – from the initial idea to completion. They are part of the SIA 112 standard and form the basis for the planning, collaboration, and remuneration of architects and specialist planners.A construction project is divided into six successive phases:Strategic planningPreliminary studiesProject planningTenderrealisationManagement

Question 2

What happens in the "Strategic Planning" phase?

Accepted Answer

The "strategic planning" phase is the starting point of every construction project, even before sketches, plans, or building applications. Here, the foundations are laid upon which all subsequent decisions are based.Typical contents of this phase include:Defining needs and objectives: What should be built and why? Who are the users? What requirements are there regarding use, design, or return on investment?Site and property assessment : Clarification of building regulations, development, usage possibilities and risks (e.g., contaminated sites, land register restrictions)Feasibility studies and rough cost estimates: Initial considerations regarding the feasibility, cost framework, schedules and the economic viability of the project.Project organisation: Who are the relevant stakeholders? How should the project be handled (e.g., general contractor, turnkey contractor, individual contracts)? Which planners and consultants are needed?This phase helps to avoid wrong decisions early on , to align the project correctly, and to ensure that it is even worth entering further planning.

Question 3

What does a feasibility study include?

Accepted Answer

A feasibility study (also called feasibility or feasibility analysis ) clarifies whether a construction project is sensible and realistically feasible at the desired location. It considers technical, legal, economic, and functional aspects.Typical contents of a feasibility study:Building code review: What is actually permitted according to the zoning plan, floor area ratio, and building and zoning regulations? Are there any restrictions (e.g., noise, easements, protected objects)?Site and zoning analysis: shape, size, development, topography, neighbouring properties and connection to utility lines (water, electricity, sewage)Area and usage concept: How much living or usable space can be created? Which typologies (e.g., apartments, commercial space) make sense?Cost estimation and profitability: Rough estimate of construction costs, sales prices or rental income, project return on investment, profitability factorsRisk analysis highlights potential pitfalls, e.g., soil conditions, potential for objections, building regulations, and procedures with authorities.Project variants (optional): Comparison of several solution approaches regarding design, utilisation, development or phasing.

Question 4

What is the difference between a preliminary design and a construction design?

Accepted Answer

The preliminary design and the construction project are two key stages within the planning phase of a construction project. However, they have different objectives and levels of detail:Preliminary design:The preliminary design phase fleshes out the basic idea . It shows what the construction project could look like and whether it complies with the legal, functional, and economic requirements.Typical contents:Preliminary design of the building volumeRough floor plans and section conceptsArea calculations (gross floor area, net living area, utilisation, etc.)Rough cost estimateVariant comparisonsGoal: A viable concept as a basis for decision-making for building owners and investors.Construction projectThe construction project is the precise elaboration of the chosen concept and forms the basis for the building application .Typical contents:Well-developed plans with all relevant dimensionsEvidence of compliance with standards (e.g. distances, access, escape routes)Construction specification and technical specificationsCost estimate based on defined specificationsAll documents for the building applicationGoal: To submit a building application and have it approved.

Question 5

What happens during the building permit application process?

Accepted Answer

The building permit application is the formal step in submitting a construction project to the relevant authority for approval . It marks the end of the planning phase and the transition to the approval and implementation process.The following happens during the building permit application process:Compilation of all documents. This includes the complete plans (floor plans, sections, elevations), the construction specification, forms, energy certificates, site plans, proof of zoning compliance, etc.Submission to the building authority: The dossier is submitted digitally or physically – depending on the municipality, canton and project type.Control by the authorities: The building authority checks whether the project complies with the legal requirements (building and zoning regulations, distance regulations, development, noise, fire protection, etc.).Public notice period (public display): The project will be publicly announced (e.g., with construction site signs and in the official gazette). During this period (usually 20 days), objections can be submitted by neighbours or third parties.Questions and clarifications: The authority may provide feedback or request additional documents. This phase often requires quick and well-founded responses.Building permit: If no objection has been raised (or if it has been resolved), and the project meets all requirements, the permit will be granted .

Question 6

What is the detailed design?

Accepted Answer

The detailed design (also called working drawings) is the phase in which a construction project is worked out in detail so that it can be built correctly and efficiently. It follows the building permit and is part of the SIA phase "Realisation" .During this phase, the following happens:Creation of detailed plans: Floor plans, sections, views and detail drawings are prepared so precisely that they can be implemented directly on the construction site.Coordination with specialist planners in architecture, structural engineering, building services (HVAC), electrical engineering and other disciplines is coordinated.Materialization and Construction: The exact construction process is defined, e.g., which materials are used, which structures are formed, how insulation or sealing is applied.Dimensions and tolerances: All plans contain exact dimensions, sections and technical details to avoid misunderstandings during construction.Basis for contractors: The detailed design serves as a working basis for construction companies and tradespeople. It is the binding specification for the construction work.

Question 7

As a building owner, do I need all SIA phases?

Accepted Answer

No, not necessarily. Which SIA phases you need as a building owner or investor depends on your project, your objectives, and the chosen planning and tendering model.In these cases, all phases are useful:They realise a construction project from the initial concept to the handover of the keys.You would like full support from an architectural firm.They value clear processes, cost transparency, and quality assurance.In these cases, individual phases are sufficient:You already have a preliminary design and only need a second opinion or optimisation.They are working with a general contractor and only need the permit planning .They want to obtain a feasibility study or strategic assessment before purchasing a property.Tip: The most crucial decisions for success or failure can be made in the early project phases, such as strategic planning , feasibility studies , or preliminary projects . Those who rely on external expertise at this stage can avoid later mistakes, cost overruns, and gaps in functionality.

Question 8

How long does a project take from planning to completion?

Accepted Answer

The duration of a construction project depends heavily on the project size, location, complexity, and organisation . While every construction project is unique, experience provides the following guidelines:Single-family house:For a classic single-family home of average complexity, the following applies:Planning & Project Development : 4–8 months (incl. strategy, preliminary design, construction project, building permit application)Approval process : 2–4 months (depending on the municipality, any objections and zoning regulations)Tender process & contractor selection : 2–6 monthsConstruction time until handover : 8–12 months (depending on construction method, season and whether it is a modular or solid construction)Total duration : approx. 15–30 months from the initial idea to moving in.Apartment building:For a small to medium-sized apartment building (approx. 6–15 apartments), the timeframe often looks like this:Planning & Project Development : 3–8 monthsApproval process : 3–6 monthsTender process & contractor selection : 6–8 monthsConstruction time until handover : 12–18 monthsTotal duration : approx. 30–40 months , depending on location, method and construction organisation.

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