Mapei Topcem Fast Drying Hydraulic Screed Binder 20kg

Description Mapei Topcem Fast Drying Hydraulic Screed Binder is a special hydraulic binder for normal setting, fast drying and shrinkage controlled screeds. When mixed with graded aggregates and water, it can produce an early drying high strength screed ready to receive floor finishes between 24hrs and 4 days. Mapei Topcem is for the formation of bonded, unbonded and floating or heated screeds on both existing and new concrete prior to the installation of wood, PVC, linoleum, ceramic tiles, natural stone, carpet or any other flooring where rapid drying is required for short installation times. Suitable for indoor and outdoor use. Some application examples: Formation of screeds set to light foot traffic after 12 hours. Formation of screeds on which ceramic tiles can be laid after 24 hours. Formation of screeds on which natural stone can be laid after 2 days. Formation of screeds on which resilient flooring, wooden flooring, waterproofing and other Mapei Systems can be laid after 4 days. Patching and repairing floor screeds where rapid restoration is required. Preparation of screeds incorporating underfloor heating systems without the need for polymer additives. Uses: High traffic areas such as airports, shopping centres, schools, hospitals etc. Fast track construction where the screed needs to be trafficked or overlaid early. Suitable for underfloor heating systems. Suitable for use where BRE screed test category A or B is required. Recommendations: Do not mix Topcem with other cement, lime, gypsum or Mapecem etc. Do not leave Mapei Topcem dry-mixed with aggregates, immediately add the correct quantity of water to the mix. Do not mix Mapei Topcem just with fine sand, use aggregates graded to BS EN 13139 0/8. Do not mix Mapei Topcem with an excessive quantity of water. Do not add water and remix Mapei Topcem after it has started to set. Recommended Dosage: Mapei Topcem binder: 250 kg/m³ Recommended mix design: 0/8 mm aggregate: 1750 kg/m³ Topcem binder: 250 kg/m³ Water: 100 kg/m³ Spreading the mix: The Mapei Topcem mix should be spread in the same way as a normal screed. A polyethylene isolating sheet (or other similar material) must be laid to create a separating layer between the screed and the supporting substrate. This separating layer also provides the function of a vapour barrier, preventing damp rising from the substrate and also dehydration of the Mapei Topcem screed due to rapid absorption of water; the absorbed water, rising subsequently would retard the drying process. Mapei Topcem screeds are prepared using the same techniques as for ordinary cement screeds, preparing levelling strips, laying the mix, carefully compacting it and then tamping for the required surface finish. Where it is necessary to incorporate piping or sheathing in the Mapei Topcem screed the upper layer which must not be less than 25 mm thick, should be reinforced with galvanized steel mesh of not more than 30×30 mm. Around the perimeter of the area and around columns etc., it is advisable to form an expansion joint about one centimetre wide between the wall and the screed with a flexible material (such as polyethylene, felt board, cork, polystyrene, etc.). If the installation of the screed is interrupted away from a construction joint cut the day joint in the screed straight down and insert pieces of 3-6 mm diameter, steel rods 20-30 cm long. They should be spaced 20-30 cm apart to ensure perfect bonding and to avoid cracks and differing levels when work is resumed. On average there is more time available for laying and working with Mapei Topcem screeds compared to traditional cement screeds. However the ambient temperature influences the setting and drying times. Construction Method: BONDED SCREEDS (Min 10mm thick): Thin screeds must be laid directly in contact with the substrate, which may be cementitious material. For other substrates, consult the MAPEI Technical Services Department. Once the substrate has been prepared sufficiently, and immediately before spreading on the Mapei Topcem mix, prepare bonding slurry with Planicrete according to the ratio in the table below. Apply a continuous, even 2-3 mm layer using a large flat brush, a scrubbing brush or a trowel. To get perfect adhesion, spread Mapei Topcem on the slurry while it is still fresh (fresh on fresh technique). If the floor is subjected to high mechanical stresses, the construction joint must be made by replacing the Planicrete cementitious bonding slurry with Eporip. Spread on Mapei Topcem using the same method described above. UNBONDED SCREED (Min 35mm thick): The Mapei Topcem mix must be laid on an isolating layer, made up of a 1200 gauge polyethylene sheet barrier, or similar, to allow for movement between the screed and the existing substrate. In case of rising damp use a waterproof membrane to form a vapour barrier underneath the screed. Mapefibre NS12 may be added to the screed at 120 g/Bag of Mapei Topcem as an additional measure. Areas of Mapei Topcem screeds containing pipes must be reinforced with light steel reinforcement (such as a hexagonal mesh). Spread the Mapei Topcem mix just like any other cement-based screed mix: use screed guides, then spread the mix and tamp thoroughly before floating to obtain a better surface finish. Place isolating material (such as polystyrene foam, cork, etc.) approx. 1 cm thick around the sides of the area and around columns before casting. If work is interrupted, place steel rods 20 to 30 cm long and 3 to 6 mm in diameter, spaced 20 to 30 cm apart, into the screed (which has been cut perpendicular to the substrate) to ensure a perfect connection between the new and the old pours and to prevent uneven joins and cracks. The Mapei Topcem mix is usually workable for a greater length of time than a conventional screed mix. Ambient temperatures may influence the setting and drying times. FLOATING SCREED (Min 55mm thick): The Mapei Topcem mix is prepared and applied in the same way as an unbonded screed. Mapefibre NS12 may be added to the screed at 120 g/Bag of Mapei Topcem as an additional measure. The insulation should have a high resistance to compression and not depress more than 3mm under the anticipated final load. Where underfloor heating pipes are incorporated, they should be located a minimum of 25 mm below the surface of the screed. Additionally reinforcing mesh if used, should be placed over the pipes. The underfloor heating may be commissioned after 4 days. Note: For under floor heating systems the screed must contain either additional reinforcing mesh or Mapefibre NS12 fibres. Dosage of the bonding slurry: Planicrete: 1 part by weight Water: 1 part by weight Mapei Topcem: 4 parts by weight To ensure adhesion, spread the slurry onto the surface to be covered immediately before the Topcem screed (fresh screed on fresh slurry). Note: For structural bonding use Eporip Epoxy Bonding Agent. Measuring the moisture content: Because of the particular composition and character of Mapei Topcem, ordinary electric moisture meters do not give reliable values; residual moisture can only be recorded with a carbide hygrometer. Consumption: Consumption varies in relation to the thickness of the screed and the dosage of Mapei Topcem. For doses of 200-250 kg of Mapei Topcem per m³ of aggregate consumption is 2-2.5 kg/m²/cm of thickness. Technical Data: Consistency: powder Colour: grey Bulk density (kg/m³): 850 Dry solids content (%): 100 EMICODE: EC1 Plus – very low emission APPLICATION DATA (at 23°C – 50% R.H.) Mixing ratio: 200-250 kg of Topcem with 1 m³ of aggregate (diameter from 0-8 mm) and 110-130 kg of water for dry aggregate Density of the mix (kg/m³): 2100 Mixing time: 5-10 minutes Working time of mix: 60 minutes Application temperature: from 5°C to 35°C Set to light foot traffic: after 12 hours Ready for use: 4 days Application of levelling compound: after 1-4 days Waiting time before installation: 24 hours for ceramic tiles 2 days for stone material 4 days for resilient and wood Residual moisture after 4 days (%): < 2.0 FINAL PERFORMANCE DATA Resistance to alkalis: excellent Resistance to oils: excellent (poor to vegetable oils) Resistance to solvents: excellent Temperature when in use: from -30°C to 90°C Product Datasheet Click here to view this product on the manufacturers website.