RonaScreed Self Smoothing Exterior Screed is a flow applied industrial flooring system. It provides a hard, durable floor surface for new floors or for renovating existing surfaces. The material gains strength quickly and can be accessed by foot traffic in 4—5 hours and by light to medium traffic after 24 hours @ 20ºC.

When applied correctly, RonaScreed Self Smoothing Exterior Screed produces a smooth, durable wearing surface. The application thickness can vary, ranging from 5mm to 40mm. For optimum performance and appearance RonaScreed Self Smoothing Exterior Screed should be applied by specialist industrial floor layers with expert knowledge of preparation, mixing and application.

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• Features & Benefits
• Achievable Surface Finish
• Preparation
• Substrate Sealing
• Substrate Priming
• Notes
• Mixing/Laying
• Estimating Guide - Sealer and Primer
• Joints and Bay Width
• Water and Chemical Resistance
• Cleaning

Features & Benefits

• Self smoothing, does not require trowelling
• Can be pumped or poured
• Very fast application reduces disruption and down time
• Economical—lower cost than resin based systems
• Suitable for exterior use
• Manufactured under a Quality Assurance Scheme to BSEN ISO 9001
• Supplied as a cement based dry powder which requires a specified quantity of clean water to produce a free flowing self-smoothing mix ready to pump or pour onto prepared, sealed and primed surfaces
• Manufactured by blending special cements, selected fillers, polymers and plasticisers
• Free from casein, other proteins and ammonia and is consequently suitable for use in hospitals and food processing areas
• Carefully formulated to provide high performance and ease of application

Achievable Surface Finish

RonaScreed Self Smoothing Exterior Screed is designed to provide a rapid strength gain, hard wearing screed or a surface suitable to receive a further layer such as vinyl or coating.

Due to the nature of the product the risk of entrapped air, pinholes and surface undulations cannot be eliminated. However efficient substrate preparation, sealing and priming, combined with correct mixing and application will provide optimum results.

It is recommended that a specialist applicator is employed. The presence of surface imperfections will not impair the performance of the product.

Preparation

The condition of the surface to be treated is of great importance. The substrate must be mechanically prepared e.g. scabbled, milled or shot blasted. All laitance and contamination must be removed to leave a clean aggregate exposed finish. Testing and assessment to BS8204 Part 3 should be conducted before proceeding with vacuum cleaning, sealing and priming.

Substrate Sealing

Seal the prepared surface by applying one or more coats of RonaScreed Self Smooth Primer diluted with 5 parts water at the rate of 0.62 litres/m². Allow to dry for not more than 36 hours; protect the surface and keep clean.

Note that inadequate sealing will increase the risk of pinholing. Very porous substrates may require the application of two or more coats of sealer. Whilst it is difficult to determine whether a substrate has been sufficiently sealed, a sheen on the surface of the substrate is an indication of adequate sealing.

Substrate Priming

Prime the sealed surface by applying one coat of RonaScreed Self Smooth Primer diluted with 3 parts water at the rate of 0.71 litres/m². Brush this well into the surface. Apply RonaScreed Self Smoothing Exterior Screed whilst primer is tacky; typically between 2-4 hours after application based on material, ambient and substrate condition of 20°C @ 65%RH.

Notes

• Major imperfections or deviations in the substrate may need to be made good before laying RonaScreed Self Smoothing Exterior Screed
• Allow the sealer to dry
• Always prime surface within 36 hours of sealing operation
• Remove ponded primer
• Always apply RonaScreed Self Smoothing Exterior Screed on to wet or tacky primer
• RonaScreed Self Smoothing Exterior Screed is self smoothing but not self levelling. It must be levelled with a pin rake before spike rolling
• RonaScreed Self Smoothing Exterior Screed is a free flowing liquid consistency screed. It is essential that prior to pouring, adequate precautions are taken to ensure that the material is retained

Mixing/Laying

RonaScreed Self Smoothing Exterior Screed may be applied either by mixer/ pump Putzmeister SP 11 THF (or similar, note that continuous feed pumps may not provide adequate dispersal of components) or when mixing smaller quantities, mix with a slow speed drill ≤ 450RPM fitted with an MR3 type helical paddle and pour onto the floor.

Pump or pour RonaScreed Self Smoothing Exterior Screed onto the prepared and sealed/primed surface and level with a pin rake. Spike rolling is necessary to expel entrapped air and must be completed before the mix begins to gel, to avoid leaving spike marks in the surface.

For pump applications it is recommended that a contractor with the necessary experience to carry out this type of work is employed.

Estimating Guide - Sealer and Primer

• 5mm screed: 8.5kg/m²
• 10mm screed: 17kg/m²
• 15mm screed: 25.5kg/m²
• 20mm screed: 34kg/m²
• 25mm screed: 42.5kg/m²

Divide surface area by 3.5 to calculate quantity of litres of RonaScreed Self Smooth Primer needed for sealing and priming e.g. 1000m² divided by 3.5 = 286 litres of Primer needed which is enough for one coat of sealer and one coat of primer).

The substrate and ambient temperature must not be less than 5°C on a rising thermometer at time of application. Materials should be at a temperature of 15°C - 20°C at time of application; lower temperatures will impair flow and surface finish. There should be light ventilation during and after laying.

Apply the material within 15 minutes of mixing (at 20°C). Protect the fresh screed from direct sunlight during the hydration/drying process. Low temperatures will reduce the flow of the wet screed and increase the risk of surface undulations and imperfections. Take extra care when working at low temperatures.

Joints and Bay Width

It is recommended that isolation joints are positioned in doorways. Large areas should be sub-divided by using temporary dividing strips to limit bay width, ensuring that a wet edge is maintained. Bay joints and movement joints in the substrate must be brought through into the topping.

Water and Chemical Resistance

RonaScreed Self Smoothing Exterior Screed has good resistance to exposure to water. If attack from solvents or acids is likely, the surface must be protected by a suitable resin based coating e.g RonaFloor HB100/200 or PU Coating.

RonaFloor HB coatings may also be used to provide decoration and colour demarcation.

When applying a coating, lightly abrade the surface to improve adhesion, When applying RonaFloor HB coatings an initial coat of RonaFloor EWB is recommended.

Cleaning

RonaScreed Self Smoothing Exterior Screed may be cleaned with a rotary scrubbing machine, using a pH neutral cleaning material. The uncoated screed will mark more quickly than one protected with a coating.

Tools and equipment should be cleaned with water immediately after use. Cured material can be removed mechanically or by acid etching.