{"product_id":"ardex-a-38-rapid-set-cement-screed","title":"Ardex A 38 Rapid Set Cement Screed","description":"\u003cdiv role=\"main\"\u003e\n \u003cp\u003eFor floor installations where downtime must be minimised, ARDEX A 38 allows tiling and stone placement to proceed within hours rather than weeks. This rapid-setting engineered screed cement is dimensionally stable and formulated to receive moisture-sensitive floor coverings, resilient flooring, parquet, and waterproofing membranes on concrete subfloors without the typical shrinkage or extended drying windows of traditional sand-cement screeds.\u003c\/p\u003e\n\n \u003ch3\u003eWhat it does\u003c\/h3\u003e\n \u003cp\u003eARDEX A 38 functions as a binder that, when mixed with graded gravel, creates a high-early-strength screed for internal and external concrete floors. It can be installed as a bonded screed, an unbonded screed over a slip-sheet or insulation, or as a heated screed over floor heating systems. By curing rapidly and controlling moisture internally, the screed achieves an early strength of approximately 20 MPa within 24 hours, meaning the surface can be tiled after 8 hours and meets the AS 1884 dryness standard for resilient flooring after 2 days.\u003c\/p\u003e\n\n \u003ch3\u003eNumbers that matter\u003c\/h3\u003e\n \u003cul\u003e\n \u003cli\u003e\n\u003cstrong\u003e8-hour tile-ready window:\u003c\/strong\u003e Allows the installation of tiles, natural stone, and terrazzo tiles just 8 hours after screed placement.\u003c\/li\u003e\n \u003cli\u003e\n\u003cstrong\u003e2-day resilient floor window:\u003c\/strong\u003e Meets drying requirements to receive parquet, textile, and resilient floor coverings after 48 hours, compliant with AS 1884.\u003c\/li\u003e\n \u003cli\u003e\n\u003cstrong\u003e15mm minimum bonded thickness:\u003c\/strong\u003e Enables thin-profile bonded screeds (up to any thickness in 50mm compacted increments) when installed wet-on-wet over a slurry bonding bridge.\u003c\/li\u003e\n \u003cli\u003e\n\u003cstrong\u003e40mm minimum unbonded thickness:\u003c\/strong\u003e The minimum depth required when installing the screed over a slip-sheet, insulating layer, or heating pipes.\u003c\/li\u003e\n \u003cli\u003e\n\u003cstrong\u003e60-minute working time:\u003c\/strong\u003e Provides a practical window for mixing, placing, levelling, and finishing, though individual batches must be finished within 10 minutes of mixing.\u003c\/li\u003e\n \u003cli\u003e\n\u003cstrong\u003e35 MPa compressive strength (28 days):\u003c\/strong\u003e Achieves high structural performance under ISO 13007.4 testing (starting at approximately 20 MPa after 1 day and 30 MPa after 3 days).\u003c\/li\u003e\n \u003c\/ul\u003e\n\n \u003ch3\u003eWhere to use it\u003c\/h3\u003e\n \u003cp\u003eARDEX A 38 is suitable for both internal and external concrete floor applications. It serves as the subfloor preparation layer prior to installing:\u003c\/p\u003e\n \u003cul\u003e\n \u003cli\u003eCeramic tiles, natural stone, and terrazzo tiles\u003c\/li\u003e\n \u003cli\u003eResilient floor coverings, vinyl, and textile carpets\u003c\/li\u003e\n \u003cli\u003eWood parquet\u003c\/li\u003e\n \u003cli\u003eARDEX Waterproofing Membranes\u003c\/li\u003e\n \u003cli\u003eHydronic or electric heated screed systems\u003c\/li\u003e\n \u003c\/ul\u003e\n\n \u003ch3\u003eInstallation and mixing\u003c\/h3\u003e\n \u003cp\u003eTo prepare the subfloor, concrete must be mechanically prepared via shot-blasting, scarifying, or diamond grinding to achieve a clean, sound, open porous matrix. Acid etching, solvents, and sweeping compounds must not be used. Direct-to-earth subfloors require an effective damp-proof membrane or an ARDEX moisture barrier system.\u003c\/p\u003e\n \u003cp\u003eFor mixing, combine 20kg of ARDEX A 38 with 100kg of ARDEX Gravel Mix (0–4mm) using a horizontal forced-action mixer or screed pump. Gradually add between 9.5 and 11 litres of clean water. Do not exceed 11 litres of water per bag, do not add other cements, and do not use additives like compound oils. Mix for 2 minutes, ensuring the mixing drum is filled to no more than three-quarters capacity.\u003c\/p\u003e\n \u003cp\u003eFor bonded installations, a slurry bonding bridge must be prepared. Mix ARDEX A 38 and ARDEX Gravel Mix at a 1:1 ratio. Separately mix ARDEX P 51 and water at a 1:1 ratio. Combine the wet and dry mixes in equal parts (1:1 ratio), apply the thin slurry to the substrate, and place the screed mix immediately wet-on-wet. Never place the screed onto dry slurry or a dry substrate.\u003c\/p\u003e\n\n \u003ch3\u003eBay sizes and joint detailing\u003c\/h3\u003e\n \u003cp\u003eTo manage movement, the screed must be placed in bays of no more than 40m², with the longest side not exceeding 8m and a length-to-width ratio of no more than 2. Adjacent bays should be separated by a 2mm gap, which can be joined the following day with epoxy to build larger contiguous panels up to 100m².\u003c\/p\u003e\n \u003cp\u003eAll perimeter walls, protrusions, direction changes, and bay divisions must be isolated with compressible foam strip (such as Abelflex) and a flexible sealant like ARDEX RA 040 Polyurethane.\u003c\/p\u003e\n\n \u003ch3\u003eLimitations\u003c\/h3\u003e\n \u003cul\u003e\n \u003cli\u003eDo not apply when ambient or substrate temperatures are below 5°C or above 35°C.\u003c\/li\u003e\n \u003cli\u003eDo not bond ARDEX A 38 directly to any ARDEX Waterproofing Membranes; the membrane must go over the cured screed.\u003c\/li\u003e\n \u003cli\u003eAvoid placing heavy loads, such as pallets of tiles or heavy machinery, on the screed at 24 hours as final compressive strength is not yet reached.\u003c\/li\u003e\n \u003c\/ul\u003e\n\u003c\/div\u003e","brand":"Ardex","offers":[{"title":"Default Title","offer_id":46776010834112,"sku":null,"price":0.0,"currency_code":"AUD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0507\/3630\/0224\/files\/ardex_a_38_screed.png?v=1758171137","url":"https:\/\/adheseal.com.au\/products\/ardex-a-38-rapid-set-cement-screed","provider":"Adheseal","version":"1.0","type":"link"}