Nowadays, it is not uncommon to find structural solutions where vehicles can drive over the heated space. In this case, a special structural layering and high-performance materials are required.
The main advantages of inverted roofs are particularly evident on flat roofs used for vehicle traffic (e.g. parking lot roofs):
- mechanical protection of insulation against rainwater
- installation of waterproofing directly on the solid slab
- application of high-strength thermal insulation.
For the construction of a vehicle-accessible inverted flat roof, depending on the layer structure, vehicle traffic intensity and load, the use of the highly durable RAVATHERM XPS 500 SL and 700 SL thermal insulation boards is recommended as thermal insulation.
By using the high-strength, high-flexibility RAVATHERM XPS thermal insulation boards, simple and economical, long-lasting structural solutions can be implemented.
Design principles
The slope of the reinforced concrete end slab or sloped concrete should be designed in accordance with the Roof Insulation Guidelines; a minimum slope of 2% is recommended.
Rainwater insulation
Rainwater insulation must be installed in such a way that the thermal insulation boards lie evenly on its surface. (Proper leveling is especially important in the case of concrete paving areas.) The rainwater insulation must be flame-melted over the entire surface, which is thus more resistant to horizontal loads, and the location of any possible failure can be easily determined.
Thermal insulation
RAVATHERM XPS 500 SL boards can be used in areas with low to medium traffic of passenger cars, while RAVATHERM XPS 700 SL thermal insulation boards are used in areas with high traffic (supermarkets, shopping malls, etc.).
Separating layer
A layer of 110-140 g/m2 surface weight, vapor-permeable polypropylene geotextile (e.g. Typar®) should be placed between the thermal insulation and the crushed stone bed. It is particularly important to use a non-absorbent film with adequate initial strength. The use of simple needle-punched geotextiles should be avoided in inverted flat roofs.
Bed
A 3-4 cm thick, compacted 4/8 mm gravel bed is recommended. This diffusion bed layer can be omitted if the load-distributing reinforced concrete slab is watertight and has a watertight seal along the expansion joints, and the structure has been checked and passed from a moisture technical point of view.
Pavement
The min. 100 mm thick concrete paving stone elements are to be laid in a 50 mm thick compacted, 4/8 mm grain size crushed stone bed, with a 3-5 mm gap. It is advisable to use elements with spacer profiles. The gaps must be sealed with fine sand with a grain size of 0/2 mm, which must be repeated after half a year. Horizontal movement of the paving and the opening of the gaps can be prevented by using reinforced concrete borders and separating strips that act as a frame for the paved surfaces. It is also advisable to frame the drains and various vertical structures with reinforced concrete borders. Regular periodic inspection of the surfaces formed with concrete paving stones is recommended, with the necessary maintenance work being carried out immediately.
Prefabricated, reinforced concrete slabs of 60/60, 90/90 or 100/100 cm in size can also be used as a covering, which are to be laid on large-diameter special underlays, according to the system administrator’s instructions. Due to the high point load, in this case, exclusively RAVATHERM XPS 700 SL thermal insulation boards are to be used.
Teljes felületű teherelosztó vasbeton lemez alkalmazása esetén a lemez vastagságának és acélszükségletének meghatározása, a dilatációs hézagok, ill. a dilatációs szakaszok együttdolgozó kialakítása szerkezettervező mérnök útmutatása alapján készül. Teherelosztó vasbetonlemez alkalmazásakor törekedni kell a dilatációk tömített kivitelezésére.
A teherhordó födém és a teherelosztó vasbeton lemez szakszerű méretezése mellett extra mértékű járműterhelés esetén csak a teherelosztó vasbetonlemez járófelület alkalmazása jöhet szóba.
In the case of using a full-surface load-distributing reinforced concrete slab, the determination of the thickness and steel requirement of the slab, the joint design of the expansion joints and the expansion sections are made based on the guidance of a structural design engineer. When using a load-distributing reinforced concrete slab, efforts must be made to ensure that the expansion joints are sealed.
In addition to the professional dimensioning of the load-bearing slab and the load-distributing reinforced concrete slab, in the case of extra vehicle loads, only the use of a load-distributing reinforced concrete slab walking surface is possible.
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