Among all types of roofing, a special place is occupied by a flat roof covered with materials capable of withstanding winds and precipitation. Until recently, it was the least used option for home improvement: roofing materials had low waterproofing properties and already began to leak after 8-10 years. Until now, in older Soviet-built houses, residents of the upper floors are struggling with the consequences of using such materials.
The appearance of new modern roofing products has completely changed the situation, and today a flat roof can be seen on many modern buildings not only in the city, but also outside it.
The issue of warming
Even elementary school students know that warm air is lighter than cold and always rises. That is why the warm air in the house first of all “leaves” through the ceiling and the insulated roof. In addition, due to the lack of an insulating layer, condensation will appear, which over time will begin to destroy the entire structure. To avoid this, an inversion roof was developed. This is a design with high heat, hydro and mechanical properties. This option of arranging the roof of the house significantly increased its durability.
The arrangement of this system is significantly different from how a flat roof was previously created: a vapor barrier layer was laid on the base plate, a thermal insulation was placed on top of it, on top of which a waterproof layer was placed, which, unfortunately, was exposed to climatic conditions and began to crack.
Features of the inversion system
The appearance of new heaters radically changed the situation. Now the technological map of the inverse roof looks like this:
- Concrete base. This may be a metal profile or floor slab.
- Concrete screed.
- Waterproofing membrane.
- Drainage material.
- Hydrophobic insulation.
- Geotextile.
- Sand and cement pillow.
- Tile or other operating material.
This list is not unchanged: the position of the layers of the roofing cake may be repeated in a different sequence or some of them may not be used at all - it all depends on the purpose of the building and the type of structure.
Roofing bias: is it necessary or not?
Despite the name, the flat roof is not absolutely flat: in order to prevent precipitation from lingering on its surface, it is imperative to arrange the slope of the inverse roof.
Otherwise, during the thaw, water will fill the microcracks of the roof and break them at night temperature drops. But due to the fact that excess moisture flows from the surface, destructive processes that reduce the life of the structure can be avoided.
Scope of application
The inverse roof device is so versatile that the design has high not only protective, but also decorative qualities, which greatly increases its functionality. The surface can be used for:
- Corporate parties.
- Meetings, conferences.
- Tea parties, banquets and other similar events.
In modern megacities, there is so little free territory, so the inversion roof can be used to arrange a summer cafe, playground, flower garden, greenhouse, terrace, pool.
Due to the beautiful appearance and functionality, this type of roof to equip the exploited area equip during construction:
- Private houses.
- Schools, kindergartens.
- Factories, factories.
- Production facilities.
- Warehouses.
Design advantages
In addition to the additional area, the obvious advantages of the inverse roof are the following indicators:
- Duration of operation - from 50 years.
- The ability to erect a structure at any time of the year.
- Thermal insulation properties. Unlike traditional flat roofs, the inversion roof retains heat many times better and at the same time protects the heat from penetrating the building in the summer.
- A variety of device options.
Disadvantages: what to look for?
One of the main disadvantages of this type of roof consumers consider high cost. However, given the reliability of the design, its aesthetics and functionality, it becomes clear: you have to pay for high quality accordingly. Disadvantages are indicators such as:
- Big weight - each square meter of a roofing cake weighs from 50 to 100 kg. Because of this, such roofs can only be erected on buildings with high load-bearing characteristics that can withstand a considerable load.
- Sophisticated repairs. It is not so easy to find a leak point under the ballast. Sometimes, to get to the right place, you have to remove a large amount of cargo, and then return it back.
- The complexity of the process. Installation of an inverse roof requires either the use of construction equipment, or considerable labor effort. It is very difficult to carry out the entire volume of work alone or together, but without experience it is also unrealistic.
Another disadvantage, experts say, is that it is not recommended to equip this roof option on buildings in areas where the climate is humid and it often rains and snows. The fact is that high humidity will cause fungi, mold and other types of living organisms to appear between the layers of hydro and thermal insulation.
It has an inversion design and weaknesses. This is the place where the waterproofing layer is adjacent to the drainage system, chimneys, parapets and other elements of the roof structure. But this is not a sentence - you can protect yourself from leaking in these places. How - more on that later.
Arrangement of protection in design weaknesses
The peculiarity of the work depends on the location of the adjoining waterproofing. So, an additional layer of waterproofing material is laid next to the drain funnel in order to avoid leakage. Place it around the perimeter. Then install a metal apron and create a slope for a stack of moisture.
If we are talking about joints where the waterproofing layer touches the walls and parapets, an additional waterproofing layer is required there. If desired, the old flat roof can be reconstructed by making an inversion model. For this:
- Restore waterproofing carpet.
- Lay the filter layer.
- Gravel is poured, which will serve as a loading layer.
Variety of designs
There are several types of inverse roofs. They are distinguished by the purpose of the upper layer:
- Green roof. Used as a relaxation area. To create, they turn to specialists who select the most suitable green spaces for this purpose. So that the plants feel at ease and do not destroy the roofing pie, the layers of the roof are laid differently. To do this, put geotextile fabric on top of the insulation, pour perlite or gravel (this is the drainage layer), then the filter layer. Lastly, the roof is covered with a layer of soil or soil.
- Construction for a parking lot. To create it, use a dense insulation. A draining layer of a structure of this type may consist of gravel or crushed stone of a small fraction (about 3 cm). The top layer is made of concrete, reinforced concrete or reinforced concrete slabs.
- Pedestrian roof. It can serve not only as a zone for movement of pedestrians, but also as a recreation area. So that the surface can withstand mechanical wear for a long time, concrete paving or ordinary ceramic tiles are used to cover it. Design feature - in the form of an insulating layer under the tile, sand, gravel or a mixture of them is used. The thickness of the insulation layer is from 3 cm.
- With gravel backfill. It is equipped on non-operated roofs. As the name implies, the surface is covered with gravel with a fraction of 25-35 mm. The thickness of the gravel layer is from 5 cm.
Installation steps
Before starting to equip the inversion roof, the lower underlying layer is strengthened and a parapet with a height of at least 20 cm is built around the perimeter. Monolithic reinforced concrete is used for its manufacture.
So that moisture does not linger, a small slope is made (at least 3 degrees). For this, a lightweight concrete mixture with extruded polystyrene is poured so that there is a slight slope. The second option to equip the slope is to use concrete mixed with expanded clay for pouring concrete. The third option is most often used: perlite or expanded clay is poured and a concrete screed is made on it. Although this method is more time-consuming, the acquisition of materials for work will significantly save money.
The slope and drain holes are placed so that the waterproofing always remains dry and does not get moisture on it.