EN 
This guide describes the process in Turkey. If you are building in another country, your local regulations will differ. How many storeys can a light steel building have? The short answer: in residential projects, the common range is one to three storeys. The earthquake code in force does not limit light steel buildings by the number of storeys but by building height; the permitted upper limit is 7 m or 10.5 m, depending on the plot's Seismic Design Class (DTS). In most projects, though, the final word rests not with the material but with the plot's zoning status and the structural calculation. In this guide, we walk through how both limits work, step by step.
Short Answer: How Many Storeys Can a Light Steel Building Have?
Giving a single number to people who ask how many storeys a steel house can have would be misleading, because the limit passes through two separate gates. The first is the engineering side: the height conditions of the earthquake code and the structural calculation of the load-bearing system. The second is the legal side: the number of storeys permitted in your plot's zoning plan in Turkey. Whichever of the two is lower is the limit that applies to your project.
On the engineering side, the basis is clear. The Turkish Building Earthquake Code (TBDY 2018) regulates light steel buildings made of cold-formed profiles in a separate chapter (Chapter 10) and sets the permitted Building Height Class (BYS) for these buildings at the lowest class, BYS=8 (Table 4.1). According to the code's Table 3.3, for BYS=8, buildings with a Seismic Design Class (DTS) of DTS=1, 1a, 2, 2a correspond to a building height of 7 m, while those with DTS=3, 3a, 4, 4a correspond to 10.5 m.
Translated into storeys: with standard floor-to-floor heights, 7 m corresponds to roughly two storeys, and 10.5 m to roughly three storeys. Because high seismic hazard zones cover a large part of Turkey, the applicable upper limit on many plots is 7 m. Single-storey, two-storey and loft designs comfortably fit within this limit; three-storey solutions become possible depending on the plot's Seismic Design Class (DTS) and the structural system configuration.
If more storeys are needed, the path is not closed off — the structural system configuration changes instead. We cover this scenario below under hybrid systems.
Engineering Factors That Determine the Number of Storeys
The storey limit for a light steel structure cannot be read off a single table; it emerges from several factors calculated together. In every project, the final decision comes from the structural design calculation prepared by the design engineer.
Profile Cross-Section and Load Transfer
In light steel structures, wall panels are both partitions and structural elements. The load from the upper storeys and the roof travels down to the foundation through the wall profiles of the storey below. As the number of storeys increases, the vertical load on the profiles at the lowest storey grows; the engineer addresses this by enlarging the profile cross-section, increasing the sheet thickness, or spacing the studs more closely. Beyond a certain point, these measures stop being economical — this is why light steel's natural field of application is low-rise buildings.
Seismic Load and Building Height
Seismic force is proportional to a building's mass. Because a light steel structure is much lighter than its reinforced concrete equivalent, the horizontal force acting on it during an earthquake is also lower — this is the system's greatest strength. Even so, the code keeps the height limited and details the calculation further: light steel buildings that resist seismic load with OSB- or plywood-clad panels fall into the high-ductility class, while those that resist it with gypsum-board or braced panels fall into the limited-ductility class. In other words, even the cladding material changes the coefficients used in the calculation; the storey decision emerges from the sum of these details.
Wind Load and Anchoring
In lightweight structures, wind is a more decisive load than it typically is in reinforced concrete, because the building's own weight contributes little resistance to overturning. As the number of storeys and the height increase, the overturning effect created by wind grows; foundation anchors and panel connection details are sized accordingly. This shows that the storey decision is not just a matter of vertical load.
How Does Zoning Status Limit the Number of Storeys?
The side of this that's often overlooked is this: in most projects, the document that actually determines how many storeys you can build is not the earthquake code but your plot's zoning status. Under Zoning Law No. 3194 in Turkey, the zoning plan that applies to each plot defines the permitted number of storeys or maximum building height (Yençok), the site coverage ratio (TAKS) and the total floor area ratio (KAKS/Emsal).
If the plan permits two storeys, you build two storeys — even if your structural system could safely carry three. The reverse also holds: the fact that the plan permits more storeys does not mean light steel can reach that height; at that point, the code's height class and the structural calculation come into play instead. Whichever of the two limits is lower wins.
TAKS and KAKS also influence the storey decision indirectly. For example, on a 500 m² plot with a TAKS of 0.20 and a KAKS of 0.40, the building can occupy at most 100 m² of ground floor footprint and use a total of 200 m² of floor area. That arithmetic naturally points you towards a two-storey configuration. The way to find out these values is the zoning status document issued by the municipality's planning department; we recommend requesting it before you buy the plot. We've explained how to obtain this document and the process that follows, step by step, in our article on how to get a building permit for a steel house.
Single-Storey, Multi-Storey and Loft Solutions
At Özok Steel, we produce projects in different storey configurations: single-storey steel villas for those who want single-level living, multi-storey steel villas for those who want to save on plot footprint, and steel villas with lofts that turn the roof slope into living space. The fact that our multi-storey and loft projects are live and built shows that, for us, the answer to "can you build more than one storey in light steel" is not theoretical — it is proven in practice.
| Solution | Typical need | Strength | Planning consideration |
|---|---|---|---|
| Single-storey | Stair-free, accessible living | Simple layout, fast installation | Uses more site coverage (TAKS) |
| Two-storey | Standard family home | Separates day and night zones, saves plot space | Staircase placement shapes the floor plan |
| With loft | Extra space, limited height | Turns the roof slope into living space | Use of sloped-ceiling areas needs planning |
| Three storeys / hybrid | Large family, demanding programme | Makes the most efficient use of the plot | May require a hybrid system depending on the Seismic Design Class |
There's another advantage of loft designs worth noting: because a loft is an intermediate level that sits within the roof slope, it adds extra living space without increasing the building height. On plots where the height limit is critical, it is a sensible option to consider instead of a third full storey.
Hybrid Systems: When You Need to Go Beyond the Limit
If the project brief doesn't fit within light steel's height limit, the solution lies in changing the structural system. Two combinations are common in the industry:
- Reinforced concrete + light steel: The basement and/or ground floor is built in reinforced concrete, with light steel storeys placed on top. This is a common configuration on sloped plots and in projects that need a basement.
- Hot-rolled steel + light steel: The main frame is built from hot-rolled profiles; light steel panels are integrated into this frame as the wall and floor system. TBDY 2018 addresses this situation explicitly: where hot-rolled steel elements are used in the lateral load-resisting system, the rules of the chapter on steel buildings apply to those elements (Article 10.1.2).
In hybrid systems, the height assessment is made according to the main structural system chosen, not the light steel chapter; the design engineer's calculation determines what height each combination can reach. This is why the realistic answer to "can you build an apartment block in light steel" mostly runs through a hybrid system: in multi-storey buildings, light steel tends to act as a complementary system rather than the main frame.
How Do You Decide on the Right Number of Storeys for Your Project?
There is a clear order for making a sound storey decision:
- Obtain the zoning status. Establish the permitted number of storeys, Yençok, TAKS and KAKS; these values set the ceiling for your project.
- Commission a geotechnical survey. Ground conditions determine the foundation type and the inputs for the seismic calculation.
- Write out your space programme. The same total area can be arranged on one storey or on two; the right distribution depends on your living habits.
- Request a preliminary structural assessment. At this stage, it becomes clear whether light steel on its own or a hybrid system suits the plot's Seismic Design Class (DTS).
- Weigh the storey configuration together with your budget. The number of storeys changes how costs are distributed across the foundation, roof, staircase and installation items.
You can review projects we have completed in different storey configurations on our work page and see the solutions we've produced for similar plot conditions.
Frequently Asked Questions
Can you build a 3-storey house in light steel?
Yes, but it depends on the conditions. Turkey's seismic code limits light steel buildings by height and allows up to 10.5 m on plots with a lower Seismic Design Class (DTS) — roughly three storeys. In high seismic hazard zones, a three-storey solution is usually built as a hybrid system. A structural assessment for your plot gives the definitive answer.
How many storeys does a steel villa with a loft count as?
A loft is a living area within the roof slope and is not a full storey height. Whether it counts as a storey depends on the zoning plan's definitions and on municipal practice in Turkey. In the structural calculation, what matters is not the storey label but total building height. That's why loft projects answer these two questions separately.
How does cost change for a multi-storey steel house?
For the same total area, more storeys mean a smaller foundation and roof, making these items more cost-efficient per square metre. On the other hand, staircases, floor decking and reinforced structural details are added. The net result depends on the plot, ground conditions and design; compare the whole project, not a single cost item.
Who determines the number of storeys?
Two authorities determine it together. The zoning status document issued by the municipality in Turkey sets the permitted number of storeys and height; the design civil engineer then calculates seismic and wind loads to confirm the structural system suits that height. The building owner sets out their needs; the final limit comes jointly from the zoning status and the structural calculation.
Can you add a light steel storey on top of an existing house?
Because of its low weight, light steel is often chosen for adding a storey. First, though, check whether the existing building's structural system can carry the added load, confirm the zoning status allows the extra storey, and obtain a renovation permit from the municipality. Adding a storey without these three conditions is risky, both for safety and under Turkish law.
To work out together how many storeys are possible given your plot's conditions, you can get in touch with us.
This article is for general information purposes. The height class and metre values given here are taken from the relevant tables of the Turkish Building Earthquake Code in force at the time of publication; seismic and zoning regulations in Turkey can be updated, and practices can vary from municipality to municipality. The figures that apply to your project are determined by the calculation your design engineer carries out under the regulations in force, together with the zoning status issued by the municipality your plot belongs to.
