Among all types of roofing, a flat roof occupies a special place, covered with materials that can withstand winds and precipitation. Until recently, it was the least used home improvement option: roofing materials had low waterproofing properties and began to leak after 8-10 years. Until now, in old Soviet-built houses, residents of the upper floors are struggling with the consequences of using such materials.
The emergence of new modern roofing products has completely changed the situation, and today the flat roof can be seen on many modern buildings not only in the city, but also beyond.
Question of insulation
Even elementary school students know that warm air is lighter than cold air and always rises. That is why the warm air in the house first of all “leaves” through the ceiling and the uninsulated roof. In addition, due to the lack of an insulating layer, condensate will appear, which over time will begin to destroy the entire structure. To avoid this, the inversion roof was developed. This is a design that hashigh heat, hydro and mechanical performance. This option for 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 carrier plate, thermal insulation was placed on top of which a waterproofing layer was placed, which, unfortunately, was exposed to climatic conditions and began to crack.
Features of the inversion system
The emergence of new heaters has radically changed the situation. Now the technological map of the inversion roof looks like this:
- Concrete base. This can be a metal profile or a floor slab.
- Concrete screed.
- Waterproofing membrane.
- Drainage material.
- Hydrophobic insulation.
- Geotextile.
- Sand-cement pad.
- Tile or other maintenance material.
This list is not fixed: 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 construction.
Roof slope: needed or not?
Despite the name, a flat roof is not absolutely flat: so that atmospheric precipitation does not linger on its surface, it is imperative to arrange an inverted roof slope.
Otherwise, during the thaw, water will fill the microcracks of the roof and at nighttemperature drops break them. But due to the fact that excess moisture drains from the surface, destructive processes that reduce the life of the structure can be avoided.
Scope of application
The device of the inverted roof is so versatile that the design has not only high protective, but also decorative qualities, which significantly increases its functionality. Surface can be used for holding:
- 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 for a summer cafe, playground, flower garden, greenhouse, terrace, pool.
Due to its beautiful appearance and functionality, this type of roof is equipped during construction to increase the usable area:
- Private houses.
- Schools, kindergartens.
- Factories, factories.
- Industrial premises.
- Warehouses.
Design Advantages
In addition to the additional area, the obvious advantages of the inversion roof are the following indicators:
- Duration of operation - from 50 years.
- The ability to build a structure at any time of the year.
- Heat-insulating properties. Unlike traditional flat roofs, inverted roofingretains heat many times better and at the same time protects against heat penetration into the building in summer.
- Variety of device options to choose from.
Flaws: what to look out for?
Consumers consider the high cost to be one of the main disadvantages of this type of roof. 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:
- Heavy weight - each square meter of 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.
- Difficult repair. It is not so easy to find a leak under the ballast. Sometimes, to get to the right place, you have to remove a large amount of weight, and then return it back.
- The complexity of the process. Installation of an inverted roof requires either the use of construction equipment or considerable labor effort. It is very difficult to complete the entire amount of work alone or together, and without experience it is unrealistic.
Another disadvantage experts call that this version of the roof is not recommended to be equipped on buildings in areas where the climate is humid and it rains and snows very often. 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 andweak spots. 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 leakage in these places. How - more on that later.
Arrangement of protection in structural weaknesses
Feature of the work depends on the junction of the waterproofing. So, near the drain funnel, in order to avoid leakage, an additional layer of waterproofing material is laid. Place it around the perimeter. Then a metal apron is installed and a slope is created for the moisture stack.
If we are talking about joints where the waterproofing layer touches walls and parapets, an additional layer of waterproofing is required there. If desired, the old flat roof can be reconstructed by making an inversion model. To do this:
- Repair the waterproofing carpet.
- Lay the filter layer.
- Pour gravel to serve as a surcharge.
Variety of designs
There are several types of inverted roofs. They are distinguished by the purpose of the top layer:
- Green roof. Used as a recreation 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 cake, the layers of the roof are laid differently. To do this, a geotextile is placed on top of the thermal insulation.fabric, perlite or gravel is poured (this is a drainage layer), then a filter layer. Lastly, cover the roof with a layer of soil or soil.
- Construction for parking. To create it, a dense insulation is used. The drainage layer of this type of structure 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 roofing. It can serve not only as a zone for the 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. Settled on non-exploited 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 inverted roof, reinforce the lower underlying layer and build a parapet at least 20 cm high around the perimeter. Monolithic reinforced concrete is used for its manufacture.
So that moisture does not linger, a slight slope is made (at least 3 degrees). To do this, a lightweight concrete mixture with extruded polystyrene is poured so that there is a slight slope. The second option for arranging the slope is to use concrete mix mixed with expanded clay for pouring. The third option is most often used: perlite is poured orexpanded clay and a concrete screed is made on it. Although this method is more time-consuming, but the purchase 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.
