RonaScreed 1 Day Overlay Rapid Dry Screed is a cement replacement for rapid drying screeds used when laying bonded, unbonded or floating screeds prior to covering with vinyl sheet or other coverings. The fast drying properties allow screeds to be covered with moisture sensitive finishes as early as one day after application.

Drying times are determined by many factors including humidity, temperature and mixing. An effective damp proof membrane must be in place.

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• Features & Benefits
• Mix Design 1—Screed By Weight (By Volume)
• Mix Design 2—Fine Concrete By Weight (By Volume)
• Measuring Surface Dryness
• Priming
• Mixing
• Placing
• Curing

Features & Benefits

• Rapid hardening—light foot traffic in 6 hours
• Rapid drying—can receive floor coverings such as tiles, vinyl, carpet, and epoxy resin after 1 day @ 75mm thick
• Apply as bonded, unbonded or floating screed
• Can be applied as thin as 25mm
• Rapid strength development
• Compressive strength >40N/mm² after 28 days
• Compatible with underfloor heating systems

Mix Design 1—Screed By Weight (By Volume)

• RonaScreed 1 Day Overlay Rapid Dry Screed: 20kg (1)
• Medium grade sharp sand: 80kg (3)
• Water: add to achieve workability
• Minimum thickness: 25mm

Mix Design 2—Fine Concrete By Weight (By Volume)

• RonaScreed 1 Day Overlay Rapid Dry Screed: 20kg (1)
• Medium grade sharp sand: 40kg (1.5)
• 10-5mm aggregate: 40kg (1.5)
• Water: add to achieve workability
• Minimum / maximum thickness: 40mm / 100mm

Measuring Surface Dryness

Laboratory tests for residual moisture indicate that RonaScreed 1 Day Overlay Rapid Dry Screed screeds will be dry enough to accept suitable vinyl and other coverings 24 hours after application. Good air movement is required to ensure low air humidity.

Priming

It is essential that where no effective damp proof membrane exists RonaScreed DPM is first applied. Refer to RonaScreed DPM data sheet.

When laying a bonded screed the surface must be mechanically prepared and tested to ensure it is suitable to restrain a bonded screed.

Clean the substrate to remove dust and debris, damp with clean water and allow the water to soak in. Remove excess water and apply a bond coat of Ronacrete Rapid Primer well brushed into the damp surface.

The screed must be laid on wet or tacky primer, dry primer must be vigorously scratched and reapplied.

Mixing

RonaScreed 1 Day Overlay Rapid Dry Screed must be machine mixed in a forced action mixer (e.g. CreteAngle pan mixer). Do not use a free fall mixer.

Mix the dry components and when evenly dispersed add sufficient clean water for adequate compaction and surface finish and to ensure full hydration of the cement. Compaction of dry mixes will be poor and strength will be low.

Placing

RonaScreed 1 Day Overlay Rapid Dry Screed must be placed immediately after mixing. The screed must be compacted and closed with a float or trowel. Avoid overworking the surface.

Thicknesses above 50mm may be placed monolithically (wet on wet) in more than one layer to ensure full compaction. Each layer should be of approximately equal thickness. To ensure satisfactory adhesion the lower layer must be raked to provide a key for the next layer. If the workability of a layer is lost it must be mechanically if it has not been raked, before applying the next layer. Then apply a bond coat of Ronacrete Rapid Primer well brushed onto the surface and apply the next layer on to the wet/tacky primer.

Curing

Exposure of RonaScreed 1 Day Overlay Rapid Dry Screed to drying winds and direct sunlight should be avoided.