General requirements for the design of flat roofs:
• in the flat roof without attic with internal dehydration, about a drop to 3°, the edge should be raised at least 10 cm above the level of the protective gravel layer – or if there isn't, above the topcoat.
• In flat roofs with a parapet, due to significant temperature fluctuations affecting the change in the length of the elements, brick attic walls should be reinforced and concrete attics should be dilated at intervals of 5 m.
• Roof slabs extending beyond the face of the wall with cantilevers should be insulated with thermal insulation with a thickness of at least 3 -4 cm.
• The area of ventilation openings in ventilated two-part flat roofs should be: 1/500 projection area. The entire surface should be ventilated evenly, and ventilation openings located on opposite sides.
• The height of the airspace at the lowest point must be minimum 10 cm. Efforts should be made to obtain much greater heights and slopes of at least 5° (about 9%).
• The structure of layers in terraces must take into account the loads occurring there. For terraces in residential buildings, the strength is at least 20 Mpa.
• In the case of internal drainage, the drainage channels should be set aside at least 1 m from the walls adjacent to the flat roof, and the flattening at the funnel must have a diameter 1 m.
• Balustrade posts should be mounted outside the sealed terrace surface, and if it is impossible, fixing with sealing flanges should be used.