- Slope screed (>1 / max. 5%)
- Vapour barrier with VELOBIT 3 mm membrane (VELOBIT 4 mm orNOVALL-I 3 mm for special situations), fully bonded on the verticals up to 10 cm above the level of the thermal insulation, and loose laid on the horizontal area.
- Thermal insulation layer (when possible, spot welded by torching directly on the vapour barrier, or bonded with oxidised bitumen)
- Double layer waterproofing system, made of:
a) first membrane: NOVATER 4 mm, offset in respect to the joints of the insulation panels, applied by torching, semi bonded on the horizontal area and fully bonded on the perimeter; laying of the second layer membrane will be preceded by the application of a strip of membrane (NOVATER 4 mm) having 30 cm width, welded for 10 cm both on the flat and on the vertical (therefore leaving free the corner);
b) second membrane: NOVABOND 4 mm applied by torching, completely bonded to the first one and on the verticals, up to 20 cm above flooring level.
For double layer systems, it is always advisable to lay the cap sheet in longitudinal direction respect to the base sheet, arranging the overlaps by having the ones of the upper layer in the middle of the first layer sheets. The sheets must be laid as well in such way that head overlap are staggered in longitudinal direction by at least 100 cm.The joints must be made by torching, overlapping the membranes (laid as “tiles”, in the direction of the slope, to favour the down flow of the water), for at least 8 cm in the case of the side and 12 cm for the head. Vertical walls and other protruding structures must be waterproofed with the same type of membrane, possibly mineralised.
- Separation layer (optional), 0.2 mm thick polyethylene film.
- Sand layer (5 cm thickness)
- Prefabricated elements, loose laid on the sand layer
In case of special situations characterised by significant dynamic loads and/or strong thermal cycles, for the double layer system, as an alternative, a NOVAGUM-P 4 mm elastomeric membrane can be used in the first layer. It is always advisable to protect the waterproofing layer above the level of the floor (on the verticals) with a layer of cementitious mortar, reinforced with light metallic mesh.