Description
ARDEX K 65 is an advanced fibre-reinforced smoothing and levelling compound for internal use, featuring Microtec technology. It is designed to rapidly smooth and level new and existing substrates prior to applying a floor finish, and unlike most levelling compounds it is formulated to be applied over timber. It can normally be walked on after approximately 2 hours at 23 degrees C. Manufactured by ARDEX Australia.
The fibre reinforcement is the reason it works over timber: timber substrates move, and an unreinforced cementitious topping cracks when they do. That, plus the low-VOC formulation and same-day walkability, is what makes it the standard choice for levelling a timber floor before carpet, vinyl or LVT. Also written ARDEX K65.
Technical Specifications
| Product type | Single-part, fibre-reinforced smoothing and levelling compound (Microtec) |
|---|---|
| Use | Internal only |
| Application thickness | 3-20 mm in one application; to 50 mm with 2-5 mm washed and dried aggregate |
| Mixing ratio | 4.8-5.0 litres of water per 20 kg |
| Mixing time | 2-3 minutes with a mixing paddle and heavy-duty drill (650 rpm) |
| Working time | Do not rework after 10 minutes |
| Walkability | Approximately 2 hours after application at 23 degrees C |
| Ready for floorcoverings | 24 hours for carpet; 48 hours for vinyl, at 23 degrees C |
| Compressive strength | Approx. 10 MPa (1 day), 20 MPa (7 days), 30 MPa (28 days) |
| Tensile bending strength | Approx. 5 MPa (1 day), 8 MPa (7 days), 10 MPa (28 days) |
| Bulk density | Approx. 1.2 kg/L |
| Fresh mortar weight | Approx. 1.8 kg/L |
| Coverage | Approx. 1.4 kg per square metre per mm – approx. 4.5 m² per bag at 3 mm |
| Packaging | 20 kg paper sack with polyethylene liner |
| Shelf life | 12 months in dry conditions, unopened, at 23 degrees C and 50% relative humidity |
Coverage Rates
ARDEX quotes approximately 4.5 square metres from one 20 kg bag at 3 mm thickness. On that basis:
| Thickness | Coverage per 20 kg bag |
|---|---|
| 3 mm (minimum) | Approx. 4.5 m² |
| 5 mm | Approx. 2.7 m² |
| 10 mm | Approx. 1.35 m² |
| 15 mm | Approx. 0.9 m² |
| 20 mm (maximum unaggregated) | Approx. 0.68 m² |
Coverage assumes a flat, level surface. Allow additional material where the surface is rough or uneven.
Where to Use
- New and existing strip timber floors
- Particleboard and plywood subfloors
- Concrete subfloors
- Compressed fibre cement flooring, terrazzo, quarry and ceramic tiles
- Concrete subfloors with electric underfloor heating, commissioned to AS 1884
- Lightweight autoclave concrete – contact ARDEX Technical Services first
Suitable floor coverings include carpet, vinyl, LVT, carpet tiles and floating floors.
How to Apply
- Prepare the subfloor – it must be solid, clean and free of dust, plaster droppings, grease, paint, oil, polish and any loosely adhered or water-softenable material. On timber floors, re-nail and firmly fix all loose boards before levelling.
- Prime – use ARDEX P 51 over standard concrete, mixed 1 part primer to 2 parts water and applied evenly with a push broom. Do not leave bare spots and brush off puddles. Allow to dry to a thin, clear film (minimum 3 hours, maximum 24 hours). Very absorbent concrete may need two coats. Use ARDEX P 82 or ARDEX P 9 on particle board.
- Mix – add the 20 kg bag to 4.8-5.0 litres of water while mixing thoroughly with a paddle and heavy-duty drill (650 rpm) for 2 to 3 minutes. Do not overwater. Concrete mixers and hand mixing are not suitable.
- Place – pour onto the prepared subfloor and spread with an ARDEX stand-up spreader or hand trowel, using a gauging tool with height adjustment to obtain an even thickness. Wear rubber or nylon studs to avoid leaving marks. Do not rework after 10 minutes.
- Build up if required – additional layers may be applied once the previous layer is dry. Above 20 mm, mix with 2-5 mm washed and dried aggregate to a maximum of 50 mm.
- Wait before covering – walkable from around 2 hours; carpet and floating floors after 24 hours; direct-stick vinyl after 48 hours.
Important Notes
- ARDEX K 65 is not suitable for the installation of direct-stick timber flooring. Floating floors and direct-stick timber flooring are not suitable substrates.
- Internal use only.
- Plywood and flooring-grade non moisture-resistant chipboard should have backs and edges sealed, be at least 18 mm thick, and be screwed or ring nailed to joists at 300 mm centres or less.
- Existing tongue and groove boards of traditional construction should be screwed or ring nailed down to the joists to give a rigidly fixed, flat, adequately braced surface. Remove any existing polish, wax or old adhesive first.
- Where underfloor heating is present, the system must be commissioned to AS 1884, then turned down to 15 degrees C before the compound and floor covering are installed, and re-commissioned gradually afterwards to avoid thermal shock.
- Low subfloor temperatures or high ambient humidity extend primer drying times. Do not install levelling compound until primers have dried thoroughly.
- Store in dry conditions in unopened packaging; shelf life is 12 months at 23 degrees C and 50% relative humidity.
