Mapei Ultralite Rapid Flex S1 15kg

• Suitable For: installing anti-fracture membrane and all types of ceramic tiles
• Area of use: INT & EXT
• Application Method: trowel
• Volume: 15KG
• Container Type: bag
• Type: adhesive
• Colour: 2 colours
• Brand: Mapei
• Manufactuer: Mapei
• Box Size: 1

Ultralite Rapid Flex S1 is suitable for installing MAPEI Mapetex anti-fracture membrane and all types of ceramic tiles and mosaics, including double-fired, single-fired, porcelain, clinker, and terracotta, on both even and uneven interior or exterior surfaces, up to 15 mm thickness. It can be used for installing natural stone tiles and mosaics on indoor and outdoor surfaces, provided the stone is not moisture-sensitive or prone to discoloration. Ideal for thin, non-mesh-backed porcelain tiles on interior and exterior walls and floors, following tile manufacturer guidelines.

Application examples:

• Fixing ceramic, natural stone, terracotta, and thin porcelain tiles on prepared substrates like cement-based screeds, concrete walls, heated screeds, cement and lime renders, gypsum plaster (with primer), and waterproof membranes (e.g., Mapelastic systems).
• Suitable for installations over existing ceramic, terrazzo, or stone floors, or floors overlaid with 15 mm exterior-grade plywood.
• Effective for balconies, terraces, and areas with restricted ventilation or limited dust tolerance, withstanding weathering, sunlight, and temperature fluctuations.

Preparation of the Substrate
Substrates for Rapid Set must be dry, stable, and free from contaminants such as grease, dust, and loose materials that could hinder adhesion. Concrete substrates should be at least 6 weeks old, and cement screeds should cure for a minimum of 3 weeks before tiling begins. Rapid drying and setting screeds made with MAPEI binders, including Topcem and Mapecem, are suitable for this product, as are pre-blended options like Topcem Pronto and Mapecem Pronto. Abraded calcium sulphate screeds should be vacuumed and primed with Eco Prim T Plus (diluted 1:2 with water) and must have a moisture content of 0.5% or lower. For flooring-grade asphalt, ensure it has sufficient strength and prime with Eco Prim Grip Plus. Alternatives to plywood for timber base overlays include a minimum of 10 mm moisture-stable cement-based tilebacker boards, while P5-grade chipboard should be securely fixed, movement-free, and primed with Eco Prim Grip Plus. Other substrates, like plaster and construction boards, must be fully dry and, if porous, primed with Primer G to control suction and prevent adhesive skinning. In damp or shower areas, protect the substrate with a MAPEI waterproofing coating, avoiding bitumen-based options. When using underfloor heating systems, level cables with Ultraplan Renovation Screed3240. Hot water piped underfloor systems should be commissioned before tiling.

Preparation of the Mix
Add 5.7-6.3 liters of water per 15 kg of Ultralite Rapid Flex S1 (grey) or 5.1-5.6 liters per 15 kg (white) to a clean mixing vessel. Mechanically mix until smooth and lump-free, then allow to stand for 3 minutes before remixing briefly. The mix has a pot life of approximately 45 minutes. Do not add extra water once the product begins to set.

Applying the Product
Apply Ultralite Rapid Flex S1 using a notched trowel to ensure full coverage of the tile backs. Begin with a thin layer on the substrate, then add the required thickness, selecting a trowel suited to the tile size. For floors and wet areas, also spread adhesive on the tile backs to ensure complete coverage. When laying thin porcelain tiles, back-buttering is recommended to prevent gaps and minimize fracture risk.

Installing the Tiles
Install tiles dry, wiping any dust from their backs with a damp sponge. Use firm pressure and a slight sliding action when fixing to ensure contact. The open time for Ultralite Rapid Flex S1 is about 15-20 minutes under normal conditions, though it may be shorter in high heat or on absorbent substrates. Continuously check for adhesive skinning, removing any affected layers before reapplying fresh material. Do not add water or new adhesive over a skinned layer. Final tile adjustments should be made within 15 minutes, and installations should be protected from rain for 3 hours and freezing conditions for 24 hours.