ALCOLIN CONTRACTORS FLOOR SCREED is a cement-based, protein free self-leveling screed which can be used as a single component system with water or as a twin pack system using a liquid additive such as ALCOLIN LATEX BOND for enhanced adhesion, flexural strength and water resistance. It is designed to provide excellent flow properties, self-smoothing characteristics, rapid walk on times and good adhesion to a variety of substrates.
General information :
Features & Benefits
- Low shrinkage, reducing risk of developing hairline cracks.
- High compressive strength.
- Protein free, resisting microbial attack. Ideal for use in hospitals.
- Excellent self-levelling properties making it easy to achieve desired level finish.
Applications
ALCOLIN CONTRACTORS FLOOR SCREED is used to prepare, repair and level uneven, internal floors prior to floor covering installations e.g. laying of carpets, vinyl or tiles, etc. It suitable for application to concrete and sand or cement screeds. It can also be applied to substrates such as anhydrite gypsum screeds, terrazzo, bitumous waterproof membranes, stone tiles, and well bonded quarry and ceramic tiles if using a priming system such as Alcolin Permo-Key Slurry Kit.
Limitations
Not suitable as a final wearing surface.
Not recommended for use as a decorative finish.
For internal use only. Protect freshly laid surfaces from draughts, direct sunlight and sources of heat.
Not suitable for areas subject to rising damp or in permanently wet conditions.
Do not screed over existing structural or movement joints.
Safety instructions
ALCOLIN CONTRACTORS FLOOR SCREED contains cement, which is alkaline and may cause skin irritation. Do not ingest. Keep away from children and pets. Do not empty into drains. Wear rubber gloves. Avoid contact with eyes. Allow any unused product to dry before disposing of the container. In the event of skin or eye contamination, rinse thoroughly with cold water. Seek medical assistance if irritation or discomfort persists. Refer to our Safety Data Sheets for further toxicological information and comprehensive handling instructions.
Surface preparation
The existing flooring should conform to the latest SABS Standards editions: SABS 021 (Code of Practice for the Waterproofing of Buildings including damp-proofing and vapour barrier installation), SANS 10109-2:2004 (Concrete Floors Part 2: Finishes to concrete floors), and supplementary specifications.
Surfaces must be sound, free from loose dust, grease, wax polish, organic growth or other contaminants.
New concrete must have matured for at least two weeks and must be thoroughly dry before any product application to avoid excessive movement due to shrinkage.
Wooden surfaces (e.g. untreated chipboard, hardboard and plywood), prime with Alcolin Permo-Key Slurry Kit.
Porous and friable surfaces (e.g. sand / cement screeds) must be primed with Alcolin Permo-Key Slurry Kit.
Smooth, non-porous surfaces (e.g. ceramic tiles or power floated and off shutter concrete) should be primed with Alcolin Permo-Key Slurry Kit.
Waterproofing bitumous membranes should always be primed with Alcolin Permo-Key Slurry Kit.
Painted and Bitumen surfaces (not waterproofing membranes) must be stripped clean and chipped to expose 80% of the substrate and then primed with Alcolin Permo-Key Slurry Kit.
Residual flooring adhesive must be scraped leaving only well adhering remnants and primed with Alcolin Permo-Key Slurry Kit.
It is essential that suitable damp-proof membranes be in place to prevent rising damp.
Underfloor heating should be turned off for at least 48 hours prior to and after application.
For Alcolin Permo-Key Slurry Kit application instructions, refer to its relevant technical data sheet.
Note: if there are any doubts about the suitability of the substrate condition, tensile pull off tests should be performed.
Mixing
- Use a mechanical mixer such as a slow electric drill fitted with a suitable paddle.
- Add approximately 4L of clean water into a clean container and slowly add 20kg of ALCOLIN CONTRACTORS FLOOR SCREED powder whilst stirring until a smooth lump free consistency is obtained.
- Stir continuously for ±2 minutes. 4. Allow the mixture to stand for 2-3 minutes and stir again.
- DO NOT ADD MORE WATER.
- Should a white film appear on the surface on standing, too much water has been added. To rectify, add more ALCOLIN CONTRACTORS FLOOR SCREED until the correct consistency is achieved.
- The mix must be used within 30 minutes, however best results are achieved if the product is used immediately. Do not mix more adhesive than can be used within this time.
NOTES: For enhanced adhesion, flexural strength and water resistance in particularly difficult conditions replace the water addition rate for ALCOLIN CONTRACTORS FLOOR SCREED with approximately 4.4L of ALCOLIN LATEX BOND.
Directions for use
- Ensure that surfaces are prepared as above.
- Pour the mix onto the surface and spread with a plasterer’s trowel to the required thickness.
- A maximum of 10mm can be applied in one application and feathered down to an edge if required. The ideal screed thickness is between 3 to 6mm.
- ALCOLIN CONTRACTORS FLOOR SCREED is self-smoothing; most trowel marks should disperse. Alternatively, a spiked roller may be used immediately after trowelling to obtain a smooth finish and to remove pin holes from the surface caused by escaping air bubbles formed during mixing. These air bubbles can also cause surface defects such as white spots when they collapse. Avoid excessive rolling as this may result in surface laitance, which will have to be removed when cured.
- Remove any ridges formed when butting up, or trowel marks remaining, with a sand block after the screed has set.
- Protect freshly laid surfaces from draughts, direct sunlight and sources of heat. These conditions may lead to rapid drying of the screed preventing the cement from fully hydrating, resulting in a weak, powdery screed which may develop cracks.
- Working in temperatures below 10°C will retard setting. Temperatures above 30°C will result in accelerated setting of the screed.
- Install expansion joints in horizontal and vertical directions every linear 5m.
Bulking up
For thicknesses greater than 10mm, the mixture can be extended by using 1 to 1 part by volume of 3mm granite chippings during the mixing stage. The flow characteristics may be impaired and the floor should be lightly trowelled to a smooth finish. Do not add extra liquid to the mix. Once dry, a standard screed mix may then be applied to improve the finish before using any adhesives.
Trafficking Accepts foot traffic after approximately 5 hours at 3mm thickness at normal room temperature.
Installation of floor coverings
Floor coverings may be installed 18 hours after screed has been laid at room temperature (20°C). At lower temperatures, or with thicker coatings, a longer setting time is required (24-48 hours depending on the conditions). Note some floor coverings or surface coatings may require specific conditioning.
Product packaging: 20kg packet
Physical data
| Type | Cement mixture |
| Appearance | Fine grey powder |
| pH | Approx. 11 |
| Solids | 100% |
Application data
| Pot life | Approx. 30 minutes at 25ºC and 50% humidity |
| Initial set | Approx. 2-3 hours at 25ºC and 50% humidity |
| Walk on time | Approx. 5 hours at 25ºC and 50% humidity |
| Final set | Approx. 24 hours at 25ºC and 50% humidity |
| Coverage | Approx. 4.2m² per 20kg packet at 3mm thickness |
Performance data
| Moisture resistance | Good |
| Compressive strength after 28 days | 45.0 MPa |
| Temperature resistance | Up to 100ºC |
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