The external raised floor is a very versatile construction system that can be installed on any type of paving, on single or double layer waterproofing membranes or on asphalt. The 20 mm raised floor system consists of:
• 20 mm slab: made of porcelain stoneware with an extra thickness of 20 mm, it has anti-slip properties and excellent resistance to loads.
• Adjustable pedestals: mainly made from recyclable and recycled material (polypropylene), they withstand acid and alkali solutions, weather and temperatures from -30° to +75°. The outdoor pedestals support the paving and have excellent mechanical strength. They are designed to be height-adjustable (from a minimum of 2.2 cm to a maximum of 10 cm, a limit recommended by Ragno) and include ancillary elements that permit correction of the gradient up to a maximum of 5%.
• Galvanised plate: the application of a galvanised plate to the underside of the slabs increases the loadbearing capacity of the building system in accordance with the EN 12825 standard.
• Mesh: the application of a mesh on the back of the slabs improves the system’s overall safety.
Instructions for installing raised paving
1. Substrate preparation
• Lay a screed with the correct gradient above the existing surface.
• Apply a waterproofing layer to prevent seepage and ensure effective rainwater drainage.
2. Slab installation
• Place the polypropylene pedestals directly on top of the waterproofing layer and add the slabs, with spacers to ensure the correct joint width.
• For a greater increase in thermal insulation/energy performance, thermal insulating panels of suitable density can be added directly between the waterproofing layer and the adjustable raised floor pedestals.
• For unprotected outdoor paving, Ragno recommends the creation of a gradient of ≥ 1.5% on the finished surface to prevent the formation of patches of standing water. In the event that standing water remains on the surface of the tiles in spite of correct installation, it must be removed mechanically with the aid of brooms or wet-and-dry vacuum cleaners.
• Before installation, architects are urged to make a careful assessment of the intended use (public or private), type and intensity of traffic, any water present, expected static and dynamic loads, and weather conditions (especially wind strength and frequency). In the case of raised paving, especially in public places, application of galvanised plate to the underside of slabs to increase load bearing capacity in accordance with the EN 12825 standard is recommended.