Description
ARDEX K 15 MICROTEC is a premium, fibre-reinforced, cement-based self-levelling and smoothing compound. It uses ARDURAPID technology, which is what allows installation at any depth in one application while still being ready for floorcoverings after 16 hours, and a high-flow formulation that lets it be laid ultra-thin. Manufactured by ARDEX Australia.
The depth-independent 16-hour figure is the part that matters on a programme. Most levelling compounds get slower as they get thicker, so a deep fill pushes the floorcovering trade back a day or more; ARDEX K 15 MICROTEC does not, and it is walkable at 2 to 3 hours and tileable from that point. Microfibre reinforcement carries the tensile load that lets it run from a feather edge up without cracking. Also written ARDEX K15 Microtec.
Technical Specifications
| Product type | Fibre-reinforced cement-based self-levelling and smoothing compound |
|---|---|
| Colour | Grey |
| Mixing ratio | 4.8-5 litres of water per 20 kg bag |
| Mixing time | 2-3 minutes with a mixing paddle and heavy-duty drill (650 rpm) |
| Working time | Do not rework after 10 minutes |
| Application thickness | Feather edge to any depth in one application |
| Walkable | Approximately 2-3 hours |
| Ready for tiles | Once walkable |
| Ready for floorcoverings | 16 hours at 23 degrees C and 50% RH, at any depth |
| Compressive strength | Approx. 15 MPa at 1 day; 25 MPa at 7 days; 30 MPa at 28 days |
| Flexural strength | Approx. 5 MPa at 1 day; 8 MPa at 7 days; 10 MPa at 28 days |
| Ball pressure hardness | Approx. 40 MPa at 1 day; 55 MPa at 7 days; 60 MPa at 28 days |
| Bulk density of powder | Approximately 1.3 kg/L |
| Weight of fresh mortar | 2.0 kg/L |
| Minimum subfloor temperature | 10 degrees C |
| Coverage | Approximately 1.7 kg powder per square metre per mm |
| Packaging | 20 kg bag |
| Shelf life | 12 months unopened, stored dry at 23 degrees C and 50% RH |
Coverage Rates
ARDEX K 15 MICROTEC consumes approximately 1.7 kg of powder per square metre for every millimetre of thickness. A 20 kg bag therefore covers:
| Thickness | Coverage per 20 kg bag |
|---|---|
| 1 mm | Approx. 11.8 m² |
| 2 mm | Approx. 5.9 m² |
| 3 mm | Approx. 4 m² |
| 5 mm | Approx. 2.4 m² |
| 10 mm | Approx. 1.2 m² |
Figures assume an even substrate. Where thickness over 10 mm is required the compound can be bulked with ARDEX aggregate mix, which improves economy on deep fills.
Where to Use
- New and existing interior concrete floors
- Over ARDEX A 38, ARDEX A 48 and ARDEX K 900 BF
- Concrete subfloors with electric underfloor heating
- Terrazzo, quarry and ceramic tiles, primed appropriately
- Existing epoxy coatings and lightweight autoclaved concrete
- Compressed fibre cement flooring and primer-treated metal
- Patching timber under underlay sheets
Several of these are substrates with special requirements – confirm with ARDEX Technical Services or the relevant technical bulletin before proceeding.
How to Apply
- Prepare the floor – concrete must be solid, clean and free of wax, grease, asphalt, latex compounds, curing and sealing compounds and other contaminants. Mechanically clean by shot blasting, scarifying, diamond grinding or shaving to create a roughened, sound, open porous surface. Acid etching is not acceptable, and solvents and sweeping compounds must not be used. The subfloor must be dry to AS 1884 and at least 10 degrees C.
- Check for moisture – where concrete moisture exceeds 80% relative humidity (ASTM F2170) or 15 g/m²/24 hrs (ASTM F1869), install a moisture stop: one coat of ARDEX WPM 300 at 3 m² per litre with ARDEX Primer Sand broadcast into the wet film, or one coat of ARDEX WPM 368 at 3 m² per litre, over which the compound goes directly. Where rising damp is present or moisture exceeds 90% RH, refer to ARDEX Technical Bulletin 192.
- Prime – on porous concrete use ARDEX P 51 mixed 1 part to 2 parts water, applied evenly with a bristle broom, leaving no bare spots and brushing off puddles. Allow to dry to a thin clear film for at least 3 hours and up to 24 hours. Very absorbent concrete needs two coats, at 1:3 then 1:1. On non-porous substrates use ARDEX P 9 diluted 1:1 by volume, after which the leveller can follow in approximately 20 minutes, or ARDEX P 82 rolled out as a thin transparent pink coat and left 3 to 24 hours to a slightly tacky film.
- Mix – add the powder into 4.8 to 5 litres of water per 20 kg bag, mixing thoroughly and quickly with a mixing paddle on a heavy-duty electric drill at 650 rpm for 2 to 3 minutes. Concrete mixers and hand mixing are not suitable. In high-stress areas such as underfloor heating or over flexible surfaces including metal, gauge instead with 1.6 litres of ARDEX E 25 and 4 litres of water per 20 kg bag.
- Place – pour onto the prepared subfloor and spread with an ARDEX gauging rake set to the required thickness, working in studded boots to avoid marking the surface. Smooth with the ARDEX stand-up spreader and a hand trowel where needed. Do not rework after 10 minutes.
- Build up if required – further layers can be applied once the previous layer has hardened sufficiently, priming between layers. For depths over 10 mm, mix the powder with 5 litres of water first, then add up to an equal weight of ARDEX aggregate mix while mixing.
Important Notes
- Interior use over dry substrates only. Do not use in areas of constant water exposure, or where the substrate is subject to permanent or intermittent moisture.
- Not designed as a decorative finish. Some colour variation is normal and does not affect performance.
- Low subfloor temperatures and high ambient humidity result in longer drying times.
- Where a subfloor vapour barrier is incomplete or missing, contact ARDEX Technical Services before proceeding.
- For power-trowelled (burnished) concrete and high-strength concrete above 35 MPa, contact ARDEX Technical Services for surface preparation advice. The same applies to steel decking.
- The compound can be pumped; confirm compatibility with ARDEX Technical Services and the pump manufacturer first.
- Store in the original unopened packaging in a dry place; shelf life is 12 months at 23 degrees C and 50% relative humidity.
Frequently Asked Questions
How much ARDEX K 15 MICROTEC do I need per square metre?
Consumption is approximately 1.7 kg of powder per square metre for each millimetre of thickness, so a 20 kg bag covers approximately 4 square metres at 3 mm. At 1 mm a bag covers roughly 11.8 square metres, at 5 mm roughly 2.4 square metres and at 10 mm roughly 1.2 square metres. Above 10 mm the compound can be bulked with ARDEX aggregate mix for economy.
How long before you can lay floorcoverings over ARDEX K 15 MICROTEC?
ARDEX K 15 MICROTEC is walkable in 2 to 3 hours and ready for floorcoverings in 16 hours at any depth, based on 23 degrees C and 50% relative humidity. Tiles can go down as soon as the compound is walkable. Low subfloor temperatures and high ambient humidity extend these times, and the subfloor must be at least 10 degrees C.
Can ARDEX K 15 MICROTEC be used in a bathroom or wet area?
The product is intended for interior use over dry substrates only. It must not be used in areas of constant water exposure, or in areas exposed to permanent or intermittent substrate moisture, as this may jeopardise the performance of both the underlayment and the floorcoverings above it. Where the concrete reads above 80% relative humidity or 15 g/m²/24 hrs, a moisture stop such as ARDEX WPM 300 or WPM 368 must be installed first.
