Achieving a sand/cement screed or render that holds its ground, resists moisture, and handles thermal shifts can be challenging. ARDEX Abacrete is a liquid polymer additive that directly addresses these site realities. It enhances your mixes, ensuring superior bond strength and improved water resistance. The result is a resilient finish that accommodates thermal movement without cracking or delamination, bringing confidence to your project's foundation.

Why this product exists

Traditional sand/cement screeds and renders often fall short when subjected to thermal expansion, contraction, or consistent moisture exposure, leading to bond failures and costly rework. ARDEX Abacrete is formulated as a liquid polymer additive to overcome these inherent limitations. It integrates directly into site-mixed sand/cement formulas, fundamentally modifying the screed or render itself, unlike standalone bonding agents that merely adhere materials together. This enhancement greatly improves shear and tensile bond strength, boosts water resistance, and allows the finished surface to accommodate thermal movement. It ensures your screeds and renders provide a durable base, whether for internal or external, commercial or residential projects on floors and walls.

The numbers that matter

ARDEX Abacrete significantly uplifts the mechanical performance of your cementitious mixes. When used in screeds, it helps achieve approximately 15 MPa compressive strength and 5 MPa flexural strength after 28 days. For renders, expect around 10 MPa compressive and 5 MPa flexural strength. These values translate to enhanced durability and resistance to cracking, critical for longevity in high-traffic or exposed areas. The 1-hour pot life offers sufficient working time for mixing and application on site.

What it's like to use

Using ARDEX Abacrete involves precise mixing with your sand and cement. For a bonding slurry coat, combine 3 parts cement to 2 parts undiluted ARDEX Abacrete by volume. This slurry is applied up to 2mm thick using a roller, brush, or trowel, with your screed or render applied while the slurry is still wet. For screeds and renders, dilute ARDEX Abacrete with water at a 1:3 ratio by volume. Then, for a screed mix, combine 21 litres of this diluted solution with 40kg of Portland cement and 120kg of clean sand. For render, use 27 litres of diluted solution with the same cement and sand quantities. Tools clean up easily with water immediately after use, preventing hardened residue.

Where this product excels

  • Flooring applications: Enhancing sand/cement screeds for all internal and external floor areas, including those with underfloor heating. It improves the screed's ability to withstand regular foot traffic and thermal cycling.
  • Wall rendering: Strengthening internal and external renders on concrete, brickwork, and blockwork. The improved bond prevents cracking and delamination, particularly useful for applications requiring up to 13mm in a single coat or thicker two-coat systems.
  • Wet area preparation: Creating durable, water-resistant screeds for shower recesses and bathrooms, ensuring necessary falls (1:60 for showers, 1:80 for internal wet areas) are maintained and bonded securely.
  • Over waterproofing membranes: Providing an effective, well-bonded screed or render layer directly over suitable waterproofing membranes, ensuring system compatibility and structural integrity.

How it fits in a real system

ARDEX Abacrete is typically introduced at the initial stages of a cementitious build-up. Its primary role is to enhance the physical properties of the screed or render mix itself. It forms a crucial interface when used as a bonding slurry coat, applied directly to the prepared substrate before the main screed or render is laid. This ensures a strong, monolithic bond. If a substrate is prone to rising damp, first apply a damp-proofing treatment like ARDEX WPM 300, then follow with an ARDEX Abacrete/cement slurry coat before applying your screed or render. This layered approach addresses both moisture ingress and mechanical performance.

Choose this when

  • When creating sand/cement screeds or renders that require enhanced shear and tensile bond strength to the substrate.
  • For improving the water resistance of cementitious floor and wall applications in wet areas or external environments.
  • When your screeds or renders need to accommodate thermal movement without risk of cracking or delamination, such as with underfloor heating.
  • To modify site-mixed sand/cement formulas, rather than using a pre-batched product, for greater control over mix properties.

Don't use this when

  • Not for: Use as a standalone waterproofing membrane. ARDEX Abacrete enhances water resistance within the mix but does not form a primary waterproofing barrier. For dedicated waterproofing, consider a product like Gripset C-1P 1 Part Flexible Cementitious Membrane.
  • Not for: A substitute for pre-mixed screeds or renders when a factory-batched, consistent solution is preferred. For pre-mixed screed solutions, consider mapei-mapecemp.
  • Not for: Applications where the substrate is not clean, firm, or strong enough. Proper substrate preparation is always critical for optimal bonding.
  • Not for: Direct application of reinforcing mesh to the substrate. Mesh must be embedded within the screed, not laid directly on the base.

While described as non-toxic and non-flammable in general terms, ARDEX Abacrete is classified as a HAZARDOUS CHEMICAL. It carries a 'Warning' signal word due to its potential to cause allergic skin reactions and eye irritation. Always wear protective gloves, eye protection, and suitable clothing during handling and mixing to ensure safety on site.