Feasibility study in Switzerland: from plot to building volume
- Simon Käslin
- Aug 17
- 10 min read
Updated: 5 hours ago
A feasibility study in Switzerland is the simplest and at the same time the most effective tool for finding out what is really possible on a plot. From initial floor plans with building outlines and a little massing, the key figures you need for your decision emerge: usable living space, building volume, possible uses and a first cost bracket. At the same time it gives you a first feel for the future project, with its outlook, orientation and basic structure. All of this is deliberately thought through in several variants so that you have a real choice. This article shows step by step how a feasibility study arrives at its results, for private clients and investors alike.
Table of contents
What is really in your plot of land?
In a free 30-minute conversation I will tell you honestly what is possible on your plot.
1. What is a feasibility study in Switzerland and what does it give you?
Every building project starts with the same question: what is actually possible on this plot, and is it worth it? A feasibility study answers exactly that. It clarifies early on whether and how a project can be realised on a specific plot, in legal, spatial and economic terms.
The core is simpler than many people think. From the requirements of the plot a rough building volume is developed, and from it the key figures that count for your decision are derived. It is not only about the building volume itself. The study goes further and also shows the possible use, the unit mix, the design and a first assessment of costs and value. In principle, though, it takes you cleanly from the plot to a tangible picture you can decide on.
What a feasibility study and a volume study fundamentally deliver and how they differ is explained in detail in the basic article on feasibility and volume studies. Here we go through concretely how such a study arrives at its results.
2. For private clients and investors alike
A feasibility study is not a tool for professionals only. It helps both of the parties that matter.
Private clients want to know: is the plot enough for our house? How much living space is in it, and could a granny flat be realised that carries part of the financing?
Investors and landowners ask different questions: how many flats are possible, which mix sells on the market, and what does that mean for income and value? How a return can be derived from figures like these is shown in the article return on investment in construction projects.
However different the goals may be, the basis is the same. Both first need a sound answer to the question of what the plot can deliver. That is exactly what the feasibility study provides.
3. How simple this tool really is
A feasibility study needs no finished planning and no detailed drawings. Initial floor plans with the building outlines and a little massing are enough, that is, a roughly modelled building volume on the plot.
This simple model yields all the key figures that matter for the decision: the countable gross floor area, the usable living space, the building volume, the possible number of flats and a first cost bracket. That is the beauty of this tool. It is lean and fast, and still meaningful enough to derive a direction from it.
4. The starting point: what your plot dictates
Every feasibility study begins with the fundamentals of the plot. What counts are the plot area, the zone with its utilisation ratio, the boundary setbacks and building heights, the topography as well as the servicing and any easements. Anyone about to buy is best advised to check these points first. The article on property analysis before purchase shows how to do this systematically, and our site analysis service covers exactly this ground in practice.
For this simplified, anonymised example we take a real hillside plot from our practice, in a suburban municipality in the Zurich area. The starting point:
Plot area: around 975 m²
Location: hillside plot with a noticeable difference in level from the road to the downhill side
Zone: residential zone with a utilisation ratio of 40 percent
Servicing in place, no onerous easements known
It is precisely the hillside location that later becomes a valuable lever. Let us go through it step by step.
5. From the plot to usable living space
The first calculation step leads from the plot to the countable gross floor area. The utilisation ratio states how much floor area is permitted per square metre of land:
Countable gross floor area = plot area x utilisation ratio
975 m² x 0.40 = 390 m² of formally countable gross floor area
These 390 m² are not the same as habitable area, however. Part of it is lost to wall thicknesses, to circulation with stairs and corridors and to plant rooms. As a rule of thumb we deduct around 25 percent for this.
So roughly 75 percent remain as usable net living space:
390 m² x 0.75 = around 290 m² of net living space
That is already a very meaningful figure. It shows the order of magnitude the project moves in, before a single floor plan has been designed.
6. From floor area to building volume
Floor area becomes building volume as soon as the storey height is added. For a rough classification a simple approximation with an average storey height of around 3.0 m is enough:
390 m² x 3.0 m = around 1,170 m³, with allowances for roof and structure roughly 1,150 to 1,300 m³
This figure matters because in the early phase many construction costs can be estimated most reliably via the price per cubic metre. The table below summarises the derivation.
Step | Calculation | Result |
Plot area | - | 975 m² |
Utilisation ratio | - | 0.40 = 40% |
Formally countable gross floor area | 975 m² x 0.40 | 390 m² |
Deduction for walls, circulation, building services | - | -25% |
Usable net living space | 390 m² x 0.75 | around 290 m² |
Building volume above ground (rough) | 390 m² x 3.00 m | 1,150 to 1,300 m³ |
All values are guide figures and depend on the canton and the project.
7. Making hidden potential visible
Now comes the part where a good feasibility study in Switzerland shows its real value. The formally countable 390 m² are not the end of the story. There is a whole series of levers anchored in building law that can be used to gain additional living space that is not counted towards the utilisation ratio.
Hillside location, basement storey: usable on the downhill side as a full storey of living space, does not count towards the utilisation ratio
Setback top floor and roof storey: these areas are not countable up to a certain proportion
Conservatory: unheated glazed extensions stay uncounted up to a certain proportion
Bay windows, projections, building length: additional area and more room depth
Ancillary areas (cellar, plant rooms, underground car park): do not count towards the utilisation ratio
On our example plot it is above all the hillside location that has an effect. Because the terrain falls away noticeably, the basement storey can be formed on the street side as a full storey of living space that legally does not count towards the utilisation ratio. Together with a setback top floor and a conservatory, the formal 390 m² could be developed into an effectively usable living area in the order of 550 to 650 m². That difference changes the value of a building considerably.
These are exactly the levers that a feasibility study makes properly visible for the first time. Which of them apply in your case depends on cantonal and municipal law and needs to be checked by a specialist.
8. More than numbers: the first feel for the project
A good feasibility study answers more than the question of areas and volume. It raises the first design questions early on and thereby gives you a first feel for your future home or your project.
That includes, for example: how is the house oriented towards the view and the sun? How are the rooms divided up, and in which direction do they open? Where is the entrance, where is the garage, and how is the garden arranged? Considerations like these go beyond pure numbers. They give the project an orientation and turn an abstract area into an idea you can identify with.
This first feel for the project is valuable. It helps you sense whether a route suits you, and it shows us in which direction we should develop the variants further. In this way the feasibility study turns from a pure calculation exercise into real project guidance.
9. Thinking in variants: from single-family house to mixed use
A feasibility study never delivers only one solution. It works with variants, and that is decisive. Only in this way do you end up with a real choice and decide consciously instead of pursuing the first idea that comes along. The same plot often carries very different routes.
Use variant | For whom | Why |
Generous single-family house | family, owner-occupied | maximum living quality |
Two-family house | two households or letting | income and flexibility |
Single-family house with granny flat | owner-occupied plus rent | eases the financing |
Small to medium apartment building | investors, densification | several units generate a return |
Mixed use of living and quiet commercial | medical practice, office, studio | additional, quiet type of use |
Whether a generous home of your own, a house with a granny flat, an apartment building or a mixed form with part living and part quiet commercial use such as a local medical practice: the study places the sensible variants side by side and makes living quality, income and flexibility comparable. For an apartment building, the article on the feasibility study for a multi-family house goes into the specifics.
10. What does building cost at this early stage?
For a rough cost estimate the price per cubic metre is suitable in the early phase. It is worth distinguishing between residential volume and basement volume, because the two do not cost the same.
The basement volume is cheaper because its fit-out is simpler. As a guide figure it lies at around CHF 700 to 800 per m³. It still has to be built, which is why it belongs in the calculation. The residential volume starts at around CHF 1,000 per m³ and rises markedly with the fit-out standard. For a mid-range fit-out standard we reckon safely with around CHF 1,200 per m³.
A clean cost framework therefore calculates the residential volume and the basement volume separately and on the basis of SIA 416. That produces a first, honest cost range for each variant. How construction costs in Switzerland are made up is explained in the article what it costs to build a house.
11. Not only the utilisation ratio: the other key ratios
An important point for context: the utilisation ratio is not the governing figure everywhere. Depending on the canton and the municipality, a building mass ratio or a floor space ratio applies instead, or there are simply limits on floor area and heights. Which ratio counts in your case and how it interacts with setbacks, heights and roof shape is what the feasibility study clarifies. You will find the background in the article utilisation ratio, GFZ and BMZ explained.
12. Assess it yourself or bring in a specialist?
You can certainly make a first rough assessment yourself. With the plot area, the zone and the relevant ratio you arrive, as shown above, at an approximate living area and volume.
For a sound basis, though, a specialist is worth it. Using the levers correctly, developing the variants sensibly and interpreting the regulations properly decides a great deal of floor area and value. A mistake at this early stage quickly costs money, many times what a study costs. That is exactly where the value of independent owner's advisory lies: we calculate it honestly, explain it so that you keep the overview, and in the end you decide yourself. What is right for your plot always depends on the specific situation.
13. From result to decision: and what comes next
The goal of the feasibility study is a clean, well-founded basis for the decision. At the end you can say with a clear conscience: this is the direction we are going. You choose consciously between the variants because you can compare area, use, design, costs and value.
Once the decision has been made, the next step is the preliminary design. There the chosen variant becomes a concrete concept with floor plans. What matters at that stage is described in the article on the preliminary design for a house build.
14. Frequently asked questions about a feasibility study in Switzerland (FAQ)
What is a feasibility study in simple terms? It is a lean tool for finding out what is possible on a plot. From floor plans with building outlines and some massing, the key figures for the decision emerge: living space, volume, possible uses and a rough cost bracket, in several variants.
How much living space do I get from my floor area? As a guide figure, around 75 percent of the countable gross floor area remains as usable net living space. Roughly 25 percent is lost to walls, circulation and building services.
Can I build more than the utilisation ratio allows? Often yes. Levers such as a hillside location with a full basement storey, a setback top floor, a conservatory or ancillary areas that are not counted can gain additional living space. What applies depends on cantonal and municipal law and needs to be checked by a specialist.
Who is a feasibility study worthwhile for? For private clients who want to know what is possible for their family, and for investors who want to clarify the number of flats, the mix and the value. The basis is the same for both.
What does a feasibility study cost? That depends on the scope and complexity, but it usually sits in the low to mid four-figure range and is therefore small in relation to the construction and land costs.
Do I need the study before buying the plot? Yes, that is strongly recommended. That way you know before the purchase whether your plans can be realised, and you negotiate from a better position.
What is really in your plot of land?
In a free 30-minute conversation I will tell you honestly what is possible on your plot.
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