FAQs

What is Flowing Screed and how is it made?

Flowing floor screed, also known as self-leveling or liquid screed, is a type of floor material used to create a smooth, level surface in preparation for the final floor finish, such as tiles, carpet, or wood. Unlike traditional cement-based screeds, which require manual smoothing, flowing screed is a fluid mixture that can spread and level itself, which results in a flatter and more consistent surface. This type of screed is commonly used in commercial and residential buildings, particularly where large, even floor areas are required or where underfloor heating is installed.

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What are the benefits of flowing screeds?

• Self-leveling: The fluidity of the mixture allows it to flow and settle evenly, eliminating the need for manual smoothing.

• Thinner layer: Flowing screeds can be applied in thinner layers than traditional screeds, usually between 25–40 mm.

• Fast drying: It often dries faster than traditional screed, allowing for quicker installation of flooring.

• Efficient heat transfer: Ideal for underfloor heating systems because of its higher thermal conductivity.

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What are the different types of screed and benefits?

There are two primary types of flowing screed:

1. Gypsum (Anhydrite) Screed: Made from calcium sulfate instead of cement. It offers high thermal conductivity and good environmental properties but requires careful handling around moisture due to its sensitivity.

2. Cement-Based Flowing Screed: Uses cement as a binder and is often mixed with additives to improve fluidity and drying times. Suitable for both interior and exterior applications.

 

Cement-based screed’s benefits—ranging from quick drying and compatibility with underfloor heating to low shrinkage and environmental friendliness—make it a strong alternative to traditional screeds, particularly for projects requiring precision, efficiency, and durability. Cemfloor Is known for It's quick drying times, and also the fact that there Is no additional work required after the Install.

 

Anhydrite screed’s benefits—such as reduced shrinkage, compatibility with underfloor heating, self-leveling properties, and environmental sustainability—make it a great choice for a range of projects requiring smooth, stable, and high-quality floor surfaces. Although It has less environmental Impact, It does take longer to dry, and there Is work required once the screed cured before follow on works can take place.

 

To give some perspective, over 90% of our customers choose to go with the cement-based screed due to the quick drying times, and lack of follow on work required.

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How can I know which screed to choose?

Choosing between Cemfloor (a cement-based liquid screed) and anhydrite (calcium sulfate-based) screed depends on several factors related to your specific project needs, environment, and preferences. Here’s a guide to help you determine which option might be best for your project:

 

Choose Cemfloor if:

• You need a fast-drying solution and have a tight project timeline.

• The area has potential exposure to moisture (e.g., kitchens, bathrooms).

• You require a thin screed layer for height constraints.

• You prioritize durability in slightly moisture-prone environments.

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Choose Anhydrite if:

• You have more time for drying and curing, especially for large projects.

• The project includes extensive underfloor heating and you want superior heat efficiency.

• Sustainability is a priority, as anhydrite is often more eco-friendly.

• The project involves very large, open spaces that benefit from a self-leveling, shrink-resistant screed.

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What warranties or guarantees does Glenalmond Contracts offer with a floor screed installations?

Warranties for Cemfloor and anhydrite screeds offer assurance for product quality, performance, and longevity, but the specifics can vary based on the supplier, manufacturer, and installer. Here’s an overview of what these warranties generally cover and their typical conditions:

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1. Cemfloor Screed Warranties

• Product Quality Guarantee: Cemfloor typically offers a warranty that covers defects in the material or manufacturing of the screed, ensuring that it performs as intended when installed correctly. This includes assurances against issues like cracking, poor adhesion, and low compressive strength.

• Performance with Underfloor Heating: Cemfloor warranties often affirm compatibility with underfloor heating systems, as long as they are installed and commissioned according to guidelines to prevent rapid temperature changes that could damage the screed.

• Warranty Period: Warranty lengths vary by supplier, project type, and location, but a typical warranty period for Cemfloor is around 10 years. Some projects may offer extended warranty terms based on specific needs.

• Installation by Approved Installers: Many Cemfloor warranties require installation by certified or approved installers to ensure proper application. This qualification often extends warranty validity, as accredited installers adhere to recommended procedures.

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2. Anhydrite Screed Warranties

• Material and Structural Integrity: Anhydrite screeds also come with warranties that cover the product against material defects and structural issues, such as shrinkage or excessive cracking, as long as installation and drying processes have been followed.

• Adherence to Drying and Moisture Control: Due to its moisture sensitivity, warranties for anhydrite screeds often specify that the screed must be dried fully before floor coverings are applied. Warranty coverage can be voided if coverings are applied over a screed that hasn’t met the required moisture levels (usually <0.5% CM for sensitive coverings).

• Warranty Duration: The warranty period for anhydrite screeds can vary, but typically ranges from 5 to 10 years. Some manufacturers may offer longer warranties for commercial projects if specific criteria are met.

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Common Conditions in Both Warranties

• Compliance with Installation Standards: Warranties are usually only valid if installation adheres to the manufacturer’s guidelines, including requirements for drying times, temperature control, and moisture testing.

• Site and Environmental Conditions: Maintaining the correct ambient conditions (temperature and humidity) during and after installation is essential for both screed types. Excess moisture or poor ventilation during curing could lead to issues not covered under warranty.

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How to Verify Warranty Terms

Both Cemfloor and anhydrite screed warranties can vary, so it’s advisable to:

• Confirm specific terms with the supplier or manufacturer directly.

• Request documentation on warranty coverage, especially for large-scale or specialized projects.

• Ensure that your installer is certified or accredited by the screed manufacturer for full warranty protection.

• Reviewing and understanding these terms will help ensure long-term performance and minimize issues that might impact warranty coverage.

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How long does the screed take to dry before the floor coverings are applied?

The time required before applying floor coverings to Cemfloor or anhydrite screed varies depending on thickness, ambient conditions, and moisture requirements of the final flooring. Here’s a breakdown for each:

 

Cemfloor Screed

• Typical Drying Rate: Around 1 mm per day up to 40 mm in ideal conditions (20°C and 60% relative humidity). For thicknesses over 40 mm, the rate slows to about 0.5 mm per day.

• Floor Covering Application: In good conditions, floor coverings can often be applied within 7–14 days for thinner screeds (up to 40 mm), but always check moisture levels first.

  • Moisture Testing: Aim for less than 2.0% moisture content (CM method) or around 75% relative humidity (RH).

 

Anhydrite Screed

• Typical Drying Rate: Approximately 0.5 mm per day under ideal conditions, so a 40 mm anhydrite screed might take around 40–60 days to dry fully.

• Floor Covering Application: Generally, wait until moisture levels are below 0.5% CM for sensitive coverings, which may take several weeks to a few months, depending on thickness and ventilation.

  • Moisture Testing: Anhydrite screed requires a very low moisture level, especially for wood or vinyl, as excess moisture can weaken the screed’s bonding.

 

Tips for Both Screeds

• Ensure adequate ventilation and maintain a stable temperature of around 20°C to help achieve faster drying.

• Use moisture tests to verify dryness, as drying times can vary with environmental conditions.

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Can screed be used with underfloor heating systems?

Both Cemfloor and Anhydrite can be used with UFH

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Does Screed require any maintenance after installation?

After applying Cemfloor or anhydrite screed, there are a few important steps to take to ensure proper curing and prevent surface issues, though both types are relatively low-maintenance during this curing phase. Here’s an overview of the recommended post-screeding practices and any ongoing maintenance considerations:

 

1. Initial Curing Period

• Cemfloor: Cemfloor requires adequate ventilation to ensure moisture can evaporate. Avoid heavy foot traffic or applying coverings until it has cured sufficiently (typically 7–14 days for light traffic). Once it’s cured, Cemfloor is durable and doesn’t require additional maintenance.

• Anhydrite: Anhydrite screed is also sensitive to ventilation. It should be protected from excess moisture during curing, and the area should be kept well-ventilated. Anhydrite screed has a longer drying time, so plan for longer before applying coverings

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2. Removing Surface Laitance

• Anhydrite: Laitance Is most likely when using Anhydrite Screed, a weak, dusty layer that can form on the surface, often needs to be removed from the top of the screed. This can typically be done by light sanding or using a mechanical buffer 7–10 days after the screed has been laid. Removing laitance helps ensure a strong bond with adhesives and floor coverings.

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3. Moisture Testing

• Both Screeds: Before applying floor coverings, especially moisture-sensitive ones like wood or vinyl, conduct a moisture test. This ensures that the screed has dried to the necessary level to prevent future moisture-related issues, like mold growth or adhesive failure.

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4. Long-Term Maintenance

• Once fully cured and covered, Cemfloor and anhydrite screeds do not require ongoing maintenance as they are protected by the final floor covering. However, it’s essential to monitor for any unexpected moisture exposure (such as leaks or flooding), as excessive moisture can damage both screeds over time, particularly anhydrite.

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By following these steps, you’ll ensure that your Cemfloor or anhydrite screed performs optimally over the long term, without any additional maintenance needs after the initial preparation.