A ventilated patio is a type of patio designed to allow air to circulate beneath the deck. This solution allows for moisture drainage and prevents water from accumulating beneath the surface. This prevents moisture from building up within the structure, which can damage materials (e.g., concrete or wood) and promote the growth of mold and mildew.
These types of terraces are particularly recommended where humidity and changing weather conditions may cause problems with the durability of the surface, e.g. peeling glued tiles in places above basements, garages, living rooms, and especially on balconies and loggias.

Deck brackets used to create the supporting structure require a suitable subfloor. Any unstable subfloor will cause the bracket to move, resulting in an unstable and uneven surface.
In the case of terraces constructed using the paving method, where the entire surface of the slab is supported (subgrade, sand, gravel, semi-dry concrete), 2 mm supports are sufficient to level the corners of the slabs and mark out even joint lines.
If we are installing a ventilated system, the foundation prepared for the supports must be durable and resistant to movements that could damage the structure.
It is possible to place the supports on concrete blocks or other stabilized foundation elements. The construction conditions for such a system must take into account ground movement and uplift of the blocks and the support, so the substructure must be prepared to prevent uplift through appropriate drainage, consideration of freezing, and soil type (sand, silt, clay, etc.). Placing the supports directly on the ground is unacceptable.
When installed on concrete screeds, terraces, ceilings and balconies, the brackets are usually placed on waterproofing, i.e. heat-sealed felt, EPDM, PVC, slurry insulation or directly on the concrete (pads under the bracket are recommended).
In the case of inverted systems, where thermal insulation is additionally installed on top of the waterproofing or directly beneath it, the structure may sag due to the lower hardness of the substrate compared to, for example, a concrete substrate. Both the felt insulation (multiple layers plus high temperatures, e.g., in summer) and the thermal insulation, especially if improperly installed with gaps underneath, can sag. The minimum permissible hardness of the substrate is 200 kPa/m², and the recommended hardness is 300 kPa/m².
In the case of a thermal insulation layer, it is most often necessary to use a top covering felt or another layer that protects the thermal insulation against UV and oxidation, in accordance with the recommendations of the thermal insulation manufacturer and construction practices.

A terrace on cantilevers has numerous advantages, both practical and aesthetic.

• Effective ventilation - A ventilated patio on cantilevers provides a space beneath the surface that allows for the free flow of air. This effectively drains away moisture that could otherwise accumulate beneath the surface. This prevents the growth of mold, mildew, and corrosion, significantly extending the life of the materials used in the patio construction.
• Easy installation - Thanks to the support system, the ventilated patio is easy to install and requires no complicated construction work. The supports can be adjusted, allowing for precise adjustment of the surface height and optimal slope, which is crucial for water drainage.
• Durability and weather resistance. A ventilated terrace on cantilevers is resistant to changing weather conditions thanks to the use of materials resistant to moisture and temperature changes. The absence of cracking joints and falling tiles is an undeniable advantage of this design.
• Protection against corrosion and mechanical damage - supports that raise the terrace surface, protect against moisture, and prevent direct contact with the ground, which in the case of traditional structures can lead to corrosion, cracks or destruction of materials.
• Aesthetics and design flexibility – a ventilated terrace on cantilevers offers extensive design options. It can be easily adapted to individual needs, both in terms of height and surface layout, with a choice of different formats, patterns, and colors.
• Convenient maintenance and access to infrastructure – the space between the surface and the ground allows for easy installation (e.g., patio lighting) or drainage. It can be quickly dismantled if necessary.

The most frequently chosen surfacing material is stoneware. Their excellent physical and visual properties quickly displace other surfaces.
Porcelain tiles imitating any surface (concrete, stone, wood) are highly practical, aesthetically pleasing, and durable. Their virtually zero water absorption makes them ideal for areas with wide temperature variations. A minimum thickness of 20 mm ensures high strength, up to 700-800 kg.
Concrete slabs, which are becoming less and less common, despite their uneven dimensions and thickness, can also be mounted on supports, which requires greater experience and precision, often additional processing of the slabs, but are still appreciated by architects and lovers of raw, uneven surfaces.
Natural stone slabs, when properly cut and polished, can create an excellent visual effect. Granite and marble are still common options for terrace finishes, especially in the common areas of large developments.
Wooden and composite decks, using joists, are a viable option, with the supporting structure also made of brackets. Siberian larch and high-quality composite decking remain popular.

Frequently asked questions about the use of additional support under terrace slabs, coupled with the lack of regulatory guidance, have led to a debate on this topic, particularly among slab manufacturers. Because slabs are susceptible to damage and cracking and are usually the weakest element of the structure, it's important to always consult the slab manufacturer's recommendations regarding the installation of their products on terrace supports. The manufacturer's warranty may be affected.
There are no conclusive studies or standards confirming the validity of adding a fifth support in the center, beneath the slab, as additional protection against slab cracking. The fact that the slab cracks at the location of the center support should be considered purely coincidental.
According to the contractors, an incorrectly positioned central support on a sagging substrate will cause the slab to hang on that support, which in turn will have more negative effects than benefits.
The recommendations of most panel manufacturers do not take into account opinions, experience, or best installation practices. They also fail to consider the mechanical properties of the supports, which are the subject of testing, for example, when issuing National Technical Assessments.
Due to the lack of clearly defined rules, it is appropriate to use all available knowledge and experience to complete the construction as well as possible.
The durability of the slab and the material from which it is made should certainly be taken into account (different materials have different strengths). Another factor is the substrate. This can be hard substrates, such as concrete screed, concrete slabs, etc., or soft substrates, such as styrodur (XPS) boards, roofing panels (PIR), etc. It's important to remember that the proper hardness of the substrate is recommended at 300 kPa/m² or higher. The hardness of the substrate directly affects the deflection of the terrace during use.
The final load capacity of the terrace is also crucial. Garden furniture, planters, decorative elements, and other components will significantly impact the structure's durability. Using the appropriate number of high-strength supports is crucial.

Ventilated terraces are structures constructed using floating technology. They do not require additional mechanical or chemical installation. There may be some areas or elements that require mechanical or chemical installation, but only to stabilize certain elements to improve the terrace's performance and durability. Polypropylene supports can be cut with an angle grinder fitted with a metal disc. Chemical fastening should be used to support installation using an adhesive appropriate for the type of materials being joined. Polymer adhesives have the widest range of applications. In a ventilated system, the surfacing material is laid with gaps through which water enters and is drained away from the balcony or terrace surface by the slope of the substructure. Installation with a sloped surface or horizontally is acceptable. Horizontal and irregular installations can result in water pooling in certain spots, drying and creating stains. Moving terrace elements, creaking or cracking tiles or boards, sliding tiles, protruding corners or uneven joint lines are all installation errors if the materials used do not have manufacturing defects or have not been damaged.