As explained in the Technical Data Sheet (see the link above), Retanol EKA BW is a tension-free high performance cementitious screeds with low shrinkage. Subject to the chosen dosage, Retanol EKA BW offers a guaranteed drying time of 7, 14 or 21 days.
Key performance advantages:
• Guaranteed drying times: 7/14/21 days
• Foot traffic after 24hrs
• Underfloor heating can be run after 24hrs (As per PCT Guidelines)
• Early compressive and flexural strength
• Ideal for underfloor heating with improved thermal conductivity
• Extended working life with short drying time
• Insensitive to moisture, therefore suitable for permanently wet areas
• For internal and external use
• UFH pipes require a minimum of 35mm coverage over the pipe (As per BS 8204)
• Bonded screeds from 25mm. In special cases, and subject to PCT site inspection and assessment, 15mm depth (with ZE Bonding Agent) is possible with 0-4mm aggregates
• Unbonded and floating screeds from 35mm
• PCT RETANOL® EKA BW Is a TUV certified screed product recognised under EU standards as a construction product with no negative impact on human health when added into a floor screed installation
TUV certification involves rigorous testing of the applications for which the product is designed. It includes verification that the product satisfies the strictest European regulations for the industry in which the product was designed for and ensures the product specifications are stated correctly. This is a significant change in the safe use of screed products across the UK construction sector. The full report is available on request.
Instruction for use
The general guidelines, data sheets and specifications for cement screeds are applicable to the mixing and laying of PCT RETANOL® EKA BW screeds. Application temperature: +5 °C to max. +28 °C (ambient and substrate temperature).
A tropical version is available upon request for higher temperature applications. Apply PCT RETANOL® EKA BW within 90 minutes of mixing. Higher temperatures will reduce and lower temperatures will increase the working life of the screed mix.
When using a 250 litres standard screed pump vessel, 50kg of cement is required for the mix designs stated below. Please refer to the PCT cement approval list for suitable types of cement.
Dosage: in standard screed pump mixing vessels with 250 litres gross capacity
(5 pump fillings are assumed at 200 litres each, amounting to 1 m³)
For Screeds up to 60mm.
• 200ml of PCT RETANOL® EKA BW Per Mix for 21 day drying – ie: 1lt per m³
• 250ml of PCT RETANOL®EKA BW Per Mix for 14 day drying – ie: 1.25lt per m³
• 350ml of PCT RETANOL®EKA BW Per Mix for 7 day drying – ie: 1.75lt per m³
For ALL screeds over 60mm use 350ml per Mix.
Fill the screed pump to about one-half with sand and the entire amount of cement (50kg) as usual. Add PCT RETANOL®EKA BW to the first mixing water (usually 5 –10 litres) and then fill the pump completely. Gradually add the required amount of residual water until a pliable consistency is obtained.
A simple test for on site moisture checking is the “damp earth test”. By squeezing a handful of screed tightly with a gloved hand, when released, the sample should retain its shape and leave the gloved hand slightly moist without running water.
Note: A mixing time of 2 minutes ensures proper blending of the products.
PCT RETANOL®EKA BW must never be mixed with other screed or mortar additives.
It is important to prepare the screed mixture correctly by ensuring you select the approved cement type, cement quantity and aggregates in accordance with DIN 1045-2, grading curve A/B, 0–8 mm, for making floor screed. 0-4mm aggregates may affect drying time and strength.
Never reactivate screed mortar which is already setting by adding additional water. This also applies to mechanical and manual finishing. Do not apply additional PCT RETANOL®EKA BW to a screed that is already setting. Always shake PCT RETANOL®EKA BW well before use. Shake the product at regular intervals (about every 30 minutes) during application. Long “standstill” periods of the container can cause the ingredients to separate and this may have a negative effect on the performance of the product.
Protect the screed from draughts, direct sunlight and excessive heat during the entire application. It may be necessary to darken large window fronts and floor-level glass facade areas to prevent over drying. The correct method to measure moisture content in all PCT RETANOL® screeds is by using a CM (Carbide Method) Moisture Test. Electronic measuring devices cannot determine the moisture content in Retanol screeds.
The application of cement screeds in winter at too low temperatures always presents a risk. Not without reason does the cement industry specify a minimum temperature of ≥+5 °C for the application of cement. Below this limit, cement reacts very slowly or not at all. The desired strengths and other screed properties might not be obtained.
For PCT RETANOL®EKA BW we have summarized the following “12 Golden PCT Winter Rules” for you:
1. Too cold: refuse the application.
Always follow the BS8204 along with all other relevant guidelines including this Technical Data Sheet.
2. Heat the mixing location and building to at least +5 °C.
Heat the mixing location and building so the cement, aggregates and applied screed do not freeze, and the temperature does not fall below +5° C.
3. Do not use heating lances.
The use of heating lances for heating the screed sand has negative effects on both the sand itself as well as the screed mortar.
4. Room climate: max. +15 °C temperature & min. 45% air humidity.
The temperature difference between the outside and inside of the building must not vary by more than +15 °C. Furthermore a minimum of 45% rH is recommended inside the building. This prevents thermal shock effects, rapid surface drying and excessive deformation.
5.Do not use floor heating during application.
Use other heating methods for “frost protection”. It is not recommended to use floor heating – even at low temperatures. Large deformations frequently occur at joints and edges when using floor heating during application.
6. Avoid warm airflows on and near the screed.
Caution regarding heating systems! “Forced heating” in the building may result in too rapid drying. High temperatures and strong blowers cause detrimental air movement.
7. Heat the building beforehand.
Start heating the building at least 5-6 days before screed application. This time is necessary for obtaining the required temperature in cold buildings.
8. Do not use kiln-dried sand.
9. Do not use antifreeze agents.
10. Warm water is no help.
Example: At 0 °C temperature of the base materials cement and sand, the addition of +30 °C warm water will only increase the temperature of the screed mixture by +1.6 °C. At this temperature neither the cement nor the additives react. Warm water is however suitable for cleaning conveyors and tools.
11. Never leave additives and cement outdoors in vehicles overnight.
Additives and cement must never be stored outdoors in vehicles overnight in the winter season.
12. Warm up.
PCT RETANOL® e.g. In warm water, at temperatures of about 15 to 20°C PCT RETANOL® has an ideal viscosity and is fully effective.
WHEN CAN SCREEDS BE WALKED ON AND SUBJECTED TO LOAD?
PCT RETANOL®EKA BW screeds can be walked on 24 hours after application. They can be subjected to load if exposed to standard site traffic after 7 days. This means that rolling loads such as wheelbarrows can be used.
Note: PCT RETANOL® EKA BW screeds are floor levelling screeds. Observe British Standards when point-loading.
Subjecting the floor to loads too early may result in damage to the screed surface and/or the screed structure and/or promote crack formation.
Screed vibrations must be permanently avoided.
The expansion foam strips must not be cut off before the laying of floor coverings or the grouting process for laying tiles has been completed, and this must be done by the floor installer.
DRYING AND VENTILATION OF ROOMS WITH HEATED AND UNHEATED PCT RETANOL®EKA BW SCREEDS:
The floor temperature must be adjusted to the floor finishing manufacturer’s requirement.
This heating information is only valid when used with this technical data sheet.
A CM moisture test must be performed before installing the final floor covering.
Shelf life of 9 months stored in ideal conditions.
All the information on this product given above is based on extensive practical experience and tests implemented by PCT Performance Chemicals GmbH. However, it is not possible to take all construction site conditions into account and to give suitable instructions for use in each case. It is therefore recommended to verify the applicability, appropriateness and practicability of this information and the intended measures by means of individual tests. PCT is responsible for the accuracy of this product information and the described properties as well as for the effect of the product. PCT reserves the right to change the product specifications. If the site is or has been supervised by PCT the user is under no obligation to check applicability and appropriateness.