Description
ARDEX P 51 is a low-VOC, concentrated, solvent-free synthetic resin dispersion for priming and sealing porous floor and wall substrates before ARDEX levelling and smoothing compounds are installed. Manufactured by ARDEX Australia.
Priming is not an optional step on a porous slab. An unprimed substrate pulls mix water out of a levelling compound before it has hydrated, which shows up as shrinkage cracking, and it lets trapped air rise through the wet compound as pinholes and bubbles. ARDEX P 51 seals the surface against both, improves adhesion, and can also serve as a short-term dust sealer on a finished compound before its wearing surface goes down. Internal applications only. Also written ARDEX P51.
Technical Specifications
| Product type | Concentrated, solvent-free synthetic resin dispersion primer |
|---|---|
| VOC | Low odour and low VOC |
| Dilution range | 1:1 to 1:3 with water, by substrate |
| Application tools | Soft broom; roller on smooth surfaces only |
| Drying time | Minimum 3 hours, maximum 24 hours, to a clear film |
| Substrate requirement | Dry, porous, firm, free from dust and release agents |
| Moisture limit | Above 80% RH in the concrete, use an ARDEX moisture mitigation system |
| Use | Internal only |
| Packaging | 5 L and 20 L plastic containers |
| Shelf life | Approximately 12 months in the originally sealed packaging, frost-free |
Dilution and Coverage
Ratios are ARDEX P 51 to water.
| Substrate | Ratio | Coverage |
|---|---|---|
| Porous concrete and sand-cement subfloors and ceilings | 1:2 | 8-10 m² per litre |
| Very porous concrete, lightweight AAC blocks and floors – first coat | 1:3 | 14-16 m² per litre |
| Very porous concrete, lightweight AAC blocks and floors – second coat | 1:1 | 8-10 m² per litre |
| Smooth concrete walls and ceilings for gypsum-bound finishing compounds | 1:3 | 14-16 m² per litre |
| Temporary trafficable concrete dust sealer | 1:3 | 14-16 m² per litre |
| Structural particleboard and plywood | 1:1 | 14-16 m² per litre |
| Sanded ceramic and porcelain tiles | 1:1 | 14-16 m² per litre |
Where to Use
- Internal porous concrete and screeds
- Plasterboard and wet area grade plasterboard
- Cement sheeting
- Structural particleboard and plywood
- Sanded ceramic and porcelain tiles
- Lightweight AAC blocks and floors
- As a temporary dust sealer over finishing and repairing compounds serving as a short-term wearing surface
How to Apply
- Check the substrate – it must be dry, porous, firm and free from dust and release agents. Where the concrete relative humidity exceeds 80% RH, an ARDEX moisture mitigation system is required before priming.
- Dilute – mix ARDEX P 51 with water in a clean container at the ratio given for the substrate in the table above.
- Spread – work the diluted primer out evenly with a soft broom. Over smooth surfaces such as tiles, timber sheet, plasterboard and cement sheet a roller may be used instead. Do not use paint rollers over concrete substrates, and do not leave any bare spots.
- Remove excess – after approximately five minutes, brush away any puddles or excess primer.
- Allow to dry – leave to dry to a clear film, a minimum of 3 hours and a maximum of 24 hours, before installing the levelling compound.
Important Notes
- Internal applications only.
- Do not install ARDEX floor levelling cements before the primer has dried thoroughly.
- Do not use paint rollers over concrete substrates.
- Do not leave bare spots – an unprimed patch will draw water out of the levelling compound and show as a defect in the finished floor.
- Very absorbent substrates need two coats, at 1:3 then 1:1, to avoid pinholes and bubbling in the levelling compound.
- Store in the originally sealed packaging in a frost-free place; shelf life is approximately 12 months.
Frequently Asked Questions
How do you dilute ARDEX P 51?
The dilution depends on the substrate. Porous concrete and sand-cement subfloors and ceilings take 1 part P 51 to 2 parts water. Very porous concrete, lightweight AAC blocks and surfaces take two coats – a first coat at 1:3 and a second at 1:1. Smooth concrete walls and ceilings for gypsum-bound finishing compounds, and use as a temporary trafficable dust sealer, take 1:3. Structural particleboard, plywood, and sanded ceramic or porcelain tiles take 1:1.
How long does ARDEX P 51 take to dry?
ARDEX P 51 dries to a clear film in a minimum of 3 hours and a maximum of 24 hours. Do not install ARDEX floor levelling cements until the primer has dried thoroughly – low subfloor temperatures and high ambient humidity extend the drying time. Brush away any puddles or excess primer about five minutes after spreading.
Can ARDEX P 51 be applied with a roller?
Only over smooth surfaces. A roller can be used on tiles, timber sheet, plasterboard and cement sheet, but paint rollers must not be used over concrete substrates – spread ARDEX P 51 evenly with a soft broom instead. Whichever tool is used, do not leave any bare spots.
