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• Features & Benefits
• Preparation
• Application
• Limitations

Features & Benefits

• Uses:
  • Forming heated screeds without the need for plasticizers
  • Forming screeds that are set for foot traffic in 12 hours and completely dry in 4 days, for installing wood parquet and resilient flooring such as rubber, PVC, linoleum, etc
  • Screeds that are ready to receive ceramic tiles after 24 hours and natural stone flooring after 2 days
  • Repairing screeds in areas where it is required to lay floorings in a short time (e.g. supermarkets, shops, residences, offices, etc.)
• Pre-blended ready-to-use mortar with normal setting and controlled shrinkage based on a special hydraulic binder and graded aggregates
• Characterized by high thermal conductivity (λ = 2 W/mK), which makes it particularly suitable for laying heated screeds
• Extremely easy to use: just mix with water. This prevents mistakes from being made in adding the correct amount of binder and properly graded aggregate, which could compromise the final performance characteristics of the screed when cured
• Ideal solution where good quality graded aggregate is hard to find or for job sites such as those in city centres where the logistics involved in mixing conventional binders can be difficult
• Workable for the same length of time as conventional cement based mortars but cures much faster
• The environmental impact of Topcem Pronto during its entire life cycle has been measured using the LCA (Life Cycle Assessment) method and the results are reported in the EPD (Environmental Product Declaration in compliance with ISO 14025 and EN 15804 standards) N° S-P-00910, certified and published by EPD International

Preparation

• Topcem Pronto can be used on any substrate as long as it is not subject to rising damp. If so, use a waterproof membrane
• For screeds from 10 to 35 mm thick, that require anchoring, the substrate must be dry, without cracks, free of dust and loose particles, varnish, wax, oil, and gypsum residues
• Topcem Pronto can be mixed in:
  • Rotating mixers
  • Normal job site mixers
  • Centrifugal mixers
  • Automatic pressure pumps
• Mix one 25 kg bag of Topcem Pronto with 1.7 l of water for at least five minutes
• Never vary the amount of water because this will weaken the mortar’s final performance
• The mix should have a semi-dry consistency
• Tamp and float the mix until a dense, smooth surface is obtained without bleeding

Application

Unbonded Screeds (35 to 60 mm thick)

The Topcem Pronto mix must be laid on an isolating layer, made up of a 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.

Areas of Topcem Pronto screeds containing pipes must be reinforced with light steel reinforcement (such as a hexagonal mesh).

Spread the Topcem Pronto 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 cardboard, 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 Topcem Pronto mix is usually workable for a greater length of time than a conventional screed mix. Ambient temperatures may influence the setting and drying times.

Bonded Screeds (from 10 to 40 mm thick)

Thin screeds must be laid directly in contact with the substrate, which may be cementitious material or made up of an old ceramic or stone floor.

Once the substrate has been prepared sufficiently, and immediately before spreading on the Topcem Pronto 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 Topcem Pronto 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 Topcem Pronto using the same method described above.

Normal electric hygrometers give values that are not reliable for Topcem Pronto screeds. It is therefore absolutely necessary that a carbide hygrometer is used to measure the level of residual humidity; this instrument shows the absolute value of humidity by weight.

Clean tools with water. Consumption 18-20 kg/m² per cm of thickness, depending on compaction.

Limitations

• Do not use Topcem Pronto on substrates subject to rising damp (place a vapour barrier in between)
• Do not mix Topcem Pronto with other binders (e.g. Mapecem, Topcem, cement, lime, gypsum, etc.) or aggregates
• Mix Topcem Pronto with the correct amount of water
• Do not add water to Topcem Pronto mix once it has begun to set
• Do not wet the surface of Topcem Pronto screed
• When there are waterproofing systems made from prefabricated flexible membranes present (such as a bitumen membrane), the isolating layer placed between the floor slab and the screed must be made from material permeable to water vapour (e.g. PP geotextile or low density non-woven fabric)