1. With IBT, we work with an INDUSTRIAL PRODUCT featuring precise dimensions and consistent parameters. This reduces on-site labor. Work on the construction site becomes easier and does not require highly qualified labor. The system saves labor, which means saving costs. With fewer workers, more work gets done. Why not benefit from that?
2. The system does not require traditional formwork—only fixing and bracing of the elements, which serve as formwork themselves.
3. The system does not require stripping of formwork, because the elements remain in place as permanent formwork.
4. Buildings constructed with the IBT system are approximately 30–50% lighter than traditional monolithic buildings. Internal and external walls are made of polystyrene (15–25 kg/m?), whereas in conventional buildings, brick masonry, for example, weighs 1000–1300 kg/m?. This results in significant savings in transportation costs for materials, lower energy consumption, and reduced greenhouse gas emissions. The lighter structure also leads to lighter and more cost-effective foundations, as well as more economical seismic-resistant structures. Why not benefit from that?
5. Savings also come from structural optimization—reinforced concrete is used only where structural forces require it. Consider the floor structures: these are thin ribbed slabs that are 30–40% lighter compared to flat reinforced concrete slabs, for example. Stair flights are also significantly lighter, as they are not entirely concrete but approximately 50% polystyrene. IBT floors are smooth on the underside, making layout planning easier and future modifications even simpler. At the same time, the floors between levels are thermally and acoustically insulated from each other, providing undeniable comfort without additional time or financial effort, as this is integrated into the system. Why not benefit from that?
6. Thermal insulation is integrated into the system, eliminating the need for additional processes such as doweling and adhesive application—entirely manual tasks. An important point for the future: insulation thicknesses are increasing. Across Europe, 20–25–30 cm insulation boards are already being installed externally and even internally, because energy is expensive and continues to rise in cost, and because administrative directives for reducing greenhouse gas emissions and improving thermal performance are becoming increasingly strict. In some European countries, building tax exemptions are granted for 10–15 years when required thermal performance standards are achieved. Why not benefit from savings in property tax as well?
How are thick insulation layers applied to traditional monolithic buildings? The answer is: expensively. Plastic anchors are not suitable for thicknesses above 15 cm. More complex mechanical fastening systems must be used, increasing cost and installation time. The IBT system has a built-in capability to provide total insulation thicknesses of up to 35 cm without technological complications. Why not benefit from that?
7. TIME.
Time is money—an old but true maxim.
How does a construction timeframe of 3–5 days per floor sound, given the level of readiness described above? A five-story building completed in one month?
The IBT system saves time and gains time.
It saves money and earns money.
8. Globally speaking, the IBT system can save up to 50% of construction time and up to 30% of the total investment costs for an entire building.
9. Operating costs can also be reduced by up to 50%, with budget items for “heating” and “cooling” potentially reduced to zero.
The question has two aspects:
Technical – how is the substitution implemented as a technical solution?
Administrative – how can it be done in compliance with regulations and legal requirements?
We will answer both.
1. TECHNICAL ASPECTS:
The IBT system is a monolithic reinforced concrete system, just like your building, presumably. Essentially, our system functions as formwork—more precisely, as permanent insulated formwork.
The vertical load-bearing structures provided in your project—columns and shear walls—will be formed using our double IBT elements. The required reinforcement according to the structural design will be placed inside the cavity, and concrete will then be poured.
The floor slabs can also be constructed using our floor formwork elements, in which additional reinforcement is placed, followed by concrete casting. Staircases are straightforward, as are non-load-bearing fa?ade and internal walls—they will be built using single-layer IBT elements.
Described this way, the process has the following specifics:
a)
It is advisable to adapt the structural design. The greatest savings in concrete and steel come from this step. The building becomes lighter overall due to a 25–30% reduction in concrete and steel, as well as the replacement of brick masonry with single IBT elements (expanded polystyrene with welded thin galvanized meshes, sprayed on both sides with shotcrete concrete).
The total building weight can be reduced by 30–40%, which also leads to savings in the foundations. The savings achieved will more than compensate for the cost of revising the structural design.
b)
It is possible that calculations may show a greater total slab thickness than originally planned—by approximately 5–10 cm per slab—due to the insulated formwork beneath. This potential drawback should be reviewed by your architect to ensure it does not lead to an unacceptable increase in the overall building height (eaves level, ridge level, etc.).
The IBT system demonstrates its best advantages in newly designed projects, as also stated in Italian technical sources.
2. ADMINISTRATIVE ASPECTS:
In a case like yours, it is necessary to refer to the applicable provisions of the Spatial Planning Act (ZUT).
Article 154, Paragraph (2), Item 5 states that substantial deviations from the approved investment project are those that change the structural system and type of structural elements and/or loads.
In such cases, a Project for Amendment of the Approved Investment Project must be prepared. This does not suspend your building permit but must precede the modified construction works.
The project includes only the affected parts:
Structural
Architectural (if required)
After approval of this amendment project, a note is added to the existing Building Permit.
Добре е познат физичния закон , че колко е по-лека сградата ,толкова по добре се държи на динамични натоварвания .
От къде идва олекотяването на сградата- там където при конвенционалното строителство се използват тухли,газобетон и други не носещи строителени елементи при системата се използват единични панели със съответната дебелина .Един квадратен метър единичен панел с двустранна мрежа и положена 3 см. от вътрешната и 3см отвътрешната циментена мазилка страна тежи 111кг. / 1м.2 ЕПС с плътност 15кг на м.3 и дебелина 8 см тежи 1,2кг+електрозаварена мрежа 1,9кг +6см циментена мазилка около 1800кг за м3-108кг. /., а тухлена стена с размер 1м2 изградена от тухла единица ,свързващ материал и мазилка двустранно тежи около 300 кг ,ако е с тухла четворка тежи около 470 кг.
Цялата тази разлика е в съотношение 1:3 и 1:4 за м2 на всички не носещи конструктивни елементи ,това е груба сметка която дава представа за олекотяването на сградата ,след като сградата е олекотена съответно рикошира въху основите шайбите, колоните и гредите т.е.върху всички вертикални и хоризонтални конструктивни елементи . В конструктивно отношение препоръчваме преизчислявяне на конструкцията на сградата, да се използва с пълно КПД олекотяването –“двигателя” на системата. Това допринася намаляване на инвестициите по отношение на стомана за армиране ,бетон за основи и др. .
Земетръсната устойчивост на тези сгради е доказана на практика в земетръсни страни като Италия, Мексико, Чили (общо 50-тина страни по света), като етажността варира от 1 до 25 етажа – са най високате, , построени с технологията, сграда в Мексико сити - силно земетръсен район.
It is a well-known physical principle that the lighter a building is, the better it performs under dynamic loads.
Where does the weight reduction come from?
In conventional construction, non-load-bearing elements such as brick, aerated concrete, and other masonry materials are used. In this system, these elements are replaced with single IBT panels of the appropriate thickness.
One square meter of a single panel with double mesh and 3 cm of cement mortar applied on each side weighs approximately 111 kg:
6 cm total cement mortar (approx. 1800 kg/m?) ? 108 kg
By comparison:
A 1 m? wall built with single brick units, mortar, and plaster on both sides weighs around 300 kg.
A 1 m? wall built with thicker (four-hole) bricks weighs approximately 470 kg.
This represents a weight ratio of approximately 1:3 to 1:4 per square meter for all non-load-bearing structural elements. This rough calculation illustrates the degree of weight reduction achieved.
Once the building is significantly lighter, the reduced load positively affects the foundations, shear walls, columns, and beams—that is, all vertical and horizontal structural elements.
From a structural engineering perspective, we recommend recalculating the building structure to fully utilize the “engine” of the system—its weight reduction potential. This allows optimization of reinforcing steel quantities, foundation concrete volumes, and other structural components, leading to reduced investment costs.
The seismic resistance of these buildings has been proven in practice in earthquake-prone countries such as Italy, Mexico, and Chile (in total, around 50 countries worldwide). Buildings constructed with this technology range from 1 to 25 stories, including high-rise buildings in Mexico City—a region known for strong seismic activity.
Openings in the walls for the installation of doors and windows are planned during the production phase of the elements, which ensures easy alignment and positioning during installation.
Structural details require careful execution, and additional reinforcing mesh must be placed around the openings as required by the design.
An installation plan with element identification is also provided by the structural engineer.
In the case of walls constructed with double CD elements, the final structure forms a continuous monolithic block, which prevents the passage and spread of fire.
Depending on the thickness of the applied shotcrete layer, the thickness of the inner layer, and the type of insulation material used, the fire resistance rating (REI) ranges between REI 120 and REI 180.
For walls constructed with single CS elements, the resulting fire resistance classification is REI 120.
The channel is not burned through, but melted using a hot-air device or a gas torch. The size of the channel is limited by the width of the hot-air stream, typically up to 5–6 cm. The melting process itself is controlled—the material simply retracts inward, creating a recessed groove.
The mesh is cut and bent back to create space for the pipe. Pipes up to ?50 mm are installed after the required channel is melted (not burned). The mesh is then bent back into its original position and tied in several places. Tying is done using standard wire and pliers, or with mechanical tying tools—which we also provide and which significantly speed up on-site work with mesh.
Finally, everything is covered with shotcrete using a cement-sand mixture.
Polypropylene water supply pipes with diameters of 15 mm and 25 mm can be threaded directly through the mesh, with cutting required only at connection points. Larger pipes such as ?110 mm, ?160 mm, etc., are generally installed within service shafts, installation ducts, or technical channels and do not interfere with the walls.
IBT elements can have a maximum production size of up to 400 cm (or smaller, for example matching the floor height) ? 112 cm.
The elements for each building are individually manufactured and tailored to the specific floor height of the project.
Regarding foundations:
When strip foundations are used, the IBT double panel (CD) can be applied without issue. The dimensions of the clear cavity—where reinforcement is placed and concrete is poured—can be manufactured according to the structural requirements of the specific project.
For basement levels, the double panel can also be used. On the external (aggressive) side, it is necessary to apply waterproofing or to use hydrophobic concrete (i.e., concrete with water-resistant additives) to protect against moisture and groundwater.
Regarding the floor panel: slabs constructed with our floor panel should be considered one-way ribbed slabs, and where required—depending on the size and geometry of the slab—the ribs can be designed as two-way (waffle-type) structures.
For the floor panel, the dimensions of the clear openings (width and height), where reinforcement is placed and concrete is poured, are manufactured according to the structural design.
It is recommended to use the floor panel for the first slab, as it simultaneously provides thermal insulation. In this way, the additional insulation operation is eliminated.
The second, third, and subsequent slabs are also constructed using the same type of floor panel.
The roof structure can likewise be built with this panel type, but with different cavity dimensions to accommodate the reinforced concrete beams.
The thickness of the panels is also determined according to the specific structural requirements of each project.
The presentation of the system as “the most integrated” is based on its ability to adapt to the architectural and structural requirements of each individual project.
THE ADVANTAGE OF OUR SYSTEM IS THAT IT PROVIDES COMPLETE FREEDOM TO ARCHITECTS, WITHOUT LIMITING THEM TO FIXED DIMENSIONS OR PREDEFINED CHARACTERISTICS.
We do not offer clients predefined elements that they must adapt to. Instead, we offer a system that adapts to the specific requirements of the building.
What are the similarities and differences between IBT and other similar systems?
Most of the cited systems on the Bulgarian market are distributed products. We are familiar with all similar systems currently represented in Bulgaria. Beyond the use of electro-welded galvanized meshes, there are several key differences that make the IBT system unique:
1. Unique range of elements
No other system offers stair elements, intermediate stair landings, and roof elements as part of a complete structural solution.
2. Wide variety and flexibility of core elements
A very important distinction of the IBT system is the diversity of its main element types:
• Double panel – 8 types
The clear cavity (where concrete is poured) can be:
8, 10, 12, 14, 16, 18, 20, or 25 cm.
Additionally, depending on the climate zone of the project, the thickness of the external EPS layer (on the aggressive/exposed side) can vary:
4, 5, or 6 cm.
This means the system actively contributes to thermal performance design.
• Single panel – 8 types
Element thickness can be:
8, 10, 12, 14, 16, 18, 20, or 25 cm.
• Floor panel (ribbed slab element)
The depth of the cavities where additional reinforcement is placed can vary according to structural needs:
10, 12, 14, 16, 18, 20, or 24 cm.
The spacing (density) of the ribs is also determined based on structural requirements.
• Roof panel
Offers the same flexibility as the floor panel.
• Stair element
Tread and riser dimensions are tailored to project requirements.
• Intermediate stair landings
Although not yet shown on the website, these elements are custom-sized according to the project.
They resemble the floor element, but allow double-sided, cassette-type reinforcement through their cavity configuration.
3. Structural efficiency
All these flexible sizing options allow elegant structural solutions. The system leverages its primary advantage—building weight reduction—resulting in:
Approximately 30% savings in reinforcing steel
Approximately 50% savings in concrete for horizontal load-bearing elements
These results have been verified across numerous completed projects.
This is what distinguishes the IBT system from other similar systems.
4. Reinforcement mesh variation
The meshes differ in spacing and wire diameter depending on panel type and structural requirements.
Final remark
The IBT system imposes no architectural limitations due to its flexibility and wide range of structural elements.
The building reinforcement is calculated by a structural engineer in accordance with Regulation No. 2.
Yes, the IBT system works with NEOPOR, which is a registered trademark of our main partner, BASF. The raw material for the EPS used in IBT elements is supplied 100% by BASF.
The NEOPOR product contains graphite particles within the EPS granules. According to BASF, this composition helps reflect various types of radiation. A particularly positive effect is the reduced transmission of infrared radiation (heat) from the inside to the outside, thereby improving thermal performance.
What is the practical difference compared to BASF’s other well-known product, STYROPOR?
The difference lies in the behavior under solar exposure. STYROPOR is negatively affected only if left exposed to direct sunlight—more specifically to the UV component of solar radiation.
In the IBT system, however, the STYROPOR core is covered with a 2.5–4 cm layer of shotcrete concrete, which protects it from direct sunlight and UV exposure.
Observations over approximately 50 years of use of BASF’s original STYROPOR product show no structural or compositional changes, nor any alteration in its physical parameters (dimensions, thickness, weight), provided it is properly protected and not exposed directly to sunlight.
Not all walls constructed with the IBT system are necessarily load-bearing.
We create an elegant monolithic reinforced concrete structure with columns and shear walls using double IBT elements. Vertical load-bearing elements are placed only where required according to structural calculations, with dimensions (thickness, width, and height) determined by the design.
The system allows variation in the thickness of floor elements, meaning the height of beam sections can be adjusted. Depending on load conditions and/or span distances, the structural engineer can design different slab-beam configurations using the IBT system, including two-way ribbed (waffle) floor structures.
The height and width of beams, the spacing between them, and the required reinforcement are all determined by the structural designer. The elements are then manufactured according to the project requirements—not the other way around.
You asked how many kilograms per square meter of reinforcement are required before concrete casting. We conducted a design experiment for a 7.20 m ? 7.20 m slab field, calculated in two versions:
as a flat (beamless) slab, and
as a ribbed slab using the IBT system,
both strictly in compliance with applicable regulations.
The results were:
Equal structural depth in both cases;
30% savings in reinforcement with the IBT system;
50% savings in concrete with the IBT system;
50% reduction in overall building weight with the IBT system, which has a positive impact by significantly reducing foundation, column, and shear wall requirements.
The question is raised because water is considered the greatest enemy of concrete.
How are large-diameter plumbing pipes installed?
In the same way as in conventional construction.
Water supply pipes with diameters of 1/2", 3/4", and 1" are integrated into the wall.
Larger pipes, such as vertical risers and drainage pipes with diameters of 50 mm, 110 mm, or 160 mm, are installed outside the walls in service shafts—exactly as in conventional construction.
What happens if they crack or leak?
The same as in conventional construction.
The contact between water and concrete is no more problematic than in traditional reinforced concrete buildings.
The answer to this question can be found in the Documents section:
- Thermal Performance Data for IBT Single Elements (CS)
- Thermal Performance Data for IBT Double Elements (CD)
The lifespan is comparable to that of any monolithic reinforced concrete building, provided that proper care is taken to prevent corrosion of the steel within the concrete (adequate concrete cover is sufficient), that the concrete itself is protected from constant exposure to freeze–thaw cycles (water penetrating and turning into ice), and that the EPS (BASF polystyrene) is properly covered and protected.
The rediscovery and widespread use of reinforced concrete dates back about 150 years. Since then, numerous institutes have tested concrete specimens—cubes and cylinders—subjecting them annually to load tests until failure. The general conclusion is that concrete is a strong and durable material, as long as it is not continuously exposed to destructive water infiltration and freeze–thaw action, which can damage even the strongest concrete. In IBT construction, the walls are fully protected against moisture penetration and erosion of the reinforced concrete.
In the IBT system, the load-bearing capacity of the building relies entirely on reinforced concrete.
The presence of EPS (BASF polystyrene) does not relate to the structural load-bearing capacity or durability of the building itself. BASF and independent institutions conduct ongoing, rigorous testing of the material, and so far, no signs of aging or material fatigue have been observed when it is properly covered—as it is in IBT technology. The elements are not exposed to direct or reflected UV radiation.
Therefore, the durability of EPS depends on proper protection through mandatory covering with mortar, plaster, cladding, or other finishes.
This is precisely the foundation of IBT technology—the building is finished by spraying both the exterior and interior surfaces with a 2–4 cm layer of cement mortar, reinforced by the galvanized mesh, which permanently and securely protects the BASF EPS core.
Plastering is performed mechanically using a turbosoil (spray pump) or shotcrete machine. The first layer is a sprayed bonding coat (shotcrete), followed by the main plaster layer, and then finishing putty if a smooth surface is required.
The difference compared to plastering brick walls lies in the fact that the technology itself ensures precise vertical alignment of the walls. This makes plastering easier, as there is no need to use traditional guide rails (“screeds”).
Uniformity is also supported by the embedded steel meshes. Shotcrete plaster is significantly stronger because it is applied under pressure, ensuring better adhesion and compaction.
The technology requires an initial sprayed layer (shotcrete), which leaves the steel meshes partially exposed. This allows the installation of various types of fa?ade finishes and even facilitates their application—such as stone cladding, wooden fa?ade systems, and others.
The sprayed layer itself provides sufficient protection against external influences, especially considering that a final fa?ade covering is applied over it.
As for the installation of gypsum board on interior walls, this can be done either using the standard method with additional metal profiles, or by pre-installing the profiles within the elements during the construction phase.
A structural engineer’s assessment of the building foundations is required.
Current regulations allow reconstructions with a certain percentage of additional load on existing buildings. In our case, this is generally not an issue, as the added structure would weigh approximately 2.5 times less than with standard construction methods.
In principle, the system is widely used for building reconstruction and renovation projects.
The clear answer is yes, an additional floor can be constructed—subject to a structural engineer’s approval.
To provide a more precise answer, please clarify what you mean by complexity:
Structural complexity? – buildings with high load requirements, buildings located in high seismic zones, buildings with rooftop swimming pools (there are such projects completed using the system)?
In all cases, construction with the IBT system should be considered monolithic construction (similar to how buildings such as Hotel “Rodina”, Kempinski “Hemus”, and others were built). Wherever increased complexity exists in conventional construction, there will also be increased complexity with our system. However, execution time with IBT will be significantly reduced, and many processes will be eliminated.
Regarding pricing: yes, complexity does affect the cost. This is why we do not publish a fixed price per square meter—there is no single fixed rate. The system includes approximately 25 different elements with varying prices, and the structural design determines which elements will be used.
Based on experience from approximately 100,000 m? of calculated gross floor area, across buildings of varying complexity, the general outcome is an average saving of around 30% in reinforcing steel and approximately 50% savings in concrete for floor slabs.
The answer to this question can be found in the Documents section:
Sound Insulation of Buildings Constructed with IBT Technology
