For structural waterproofing jobs requiring SILCOR polyurethane-based membranes, Silcor Primer BS establishes the critical physical bond to the substrate. This fast-drying, single-pack modified polyurethane primer replaces Aquagard M Clear Primer, securing adhesion across key construction substrates before membrane application.
Silcor Primer BS penetrates and seals porous substrates to promote maximum adhesion for subsequent polyurethane coatings. The fast-drying resin system develops a water-resistant film quickly after application. This resistance protects the prepared concrete or masonry structure from water damage if wet weather interrupts the installation sequence before the waterproof membrane is applied. It also maintains its ability to promote adhesion when applied in cold weather conditions.
The primer is formulated for application on rigid, structurally sound construction substrates, including:
Do not apply Silcor Primer BS to substrates with a moisture content exceeding 5%. Detailing according to the NCC, AS 4654.2 (external above ground), and AS 3740 (internal wet areas) must be completed before priming starts. Any applied primer left uncoated for more than 72 hours cannot be recoated or recovered; it must be completely removed by diamond grinding down to the base substrate and re-primed.
Ensure all substrates are smooth, clean, and dry. Completely remove all dust, laitance, loose matter, oil, curing compounds, and form release agents. Concrete must be aged 14 to 28 days depending on slab thickness and the specific primer system. Apply one coat directly from the container using a brush, roller, or spray. Allow the coating to become completely tack-free before applying the polyurethane membrane.
No, this primer is specifically formulated for use with SILCOR polyurethane-based membranes only. Using it outside this system may compromise bond integrity and affect performance.
You must apply the membrane within 24 hours of priming. If this window is exceeded, wipe the primed area with Xylene and re-prime lightly. Any primer not coated within 72 hours requires full mechanical removal and re-priming.
SILCOR Primer BS is designed for substrates with a maximum moisture content of 5%. For substrates with moisture content up to 10%, use SILCOR Primer BW Clear or EPOCOTETM F100W Clear instead.
At 20°C, SILCOR Primer BS dries to a tack-free state in 30 to 60 minutes. This quick drying time helps maintain project schedules and reduces the risk of weather delays.
| Application | Key benefit | Primary trades |
|---|---|---|
| Priming concrete surfaces for SILCOR membranes | Ensures a strong physical bond to concrete, preventing delamination of the waterproofing system. | Waterproofers, Builders |
| Priming cement render for SILCOR membranes | Establishes reliable adhesion on cementitious renders, crucial for durable waterproofing. | Waterproofers, Renderers |
| Priming compressed fibre cement (CFC) sheets | Prepares CFC sheets to accept SILCOR polyurethane membranes, ensuring system integrity. | Waterproofers, Cladders |
| Priming metal substrates for waterproofing | Promotes robust adhesion to metal, maintaining performance even in cooler conditions. | Waterproofers, Metal fabricators |
| Priming brickwork prior to waterproofing | Provides a solid foundation for SILCOR membranes on brick, ensuring consistent system performance. | Waterproofers, Bricklayers |
Preparation is critical for a first-time-right bond. All detailing (fillets, joints) must be completed *before* priming starts.
Substrates must be structurally sound (min. 25 MPa), smooth, clean, and dry. Remove all dust, laitance, loose matter, oil, or curing compounds.
Ensure surfaces are clean, dry, and free of all contaminants, grease, or release agents.
This primer has strict moisture limits. Do not guess.
Use a calibrated moisture meter. The substrate moisture content MUST be 5% or less.
Apply a single, consistent coat as soon as preparation and testing are complete.
Apply one coat directly from the container using a brush, roller, or spray. Target a minimum application rate of approximately 0.3kg/m².
Adhering to the recoat window is essential for the chemical bond and to avoid callbacks.
Apply the selected SILCOR membrane *within 24 hours* of the primer becoming tack-free.
Wipe the entire primed area with Xylene. Let the solvent flash off completely. Re-prime with a light coat at approx. 0.15kg/m².
Signal Word: Danger
Wear protective gloves (rubber), safety glasses with side shield protection, protective clothing, face protection, and hearing protection.
Use only outdoors or in a well-ventilated area. Ensure good interior ventilation, particularly at floor level, as vapours are heavier than air. Use explosion-proof electrical, ventilating, and lighting equipment.
Store SILCOR Primer BS in a cool, dry, and well-ventilated place. Keep containers tightly closed and away from heat, sparks, open flames, and other ignition sources. Store locked up and protected from frost. Unopened cans have a shelf life of 12 months. Dispose of contents and containers in accordance with local, regional, national, or international regulations; do not discharge into sewage systems or with household garbage.
Proper substrate preparation is critical for the long-term adhesion of SILCOR membranes. Follow these guidelines to ensure a reliable bond.
Substrates: Concrete masonry, off-form concrete, in-situ concrete slabs and topping, shotcrete, cement render, light-weight foamed concrete, pre-cast concrete panels.
Surface prep: Substrates must be structurally sound, smooth, clean, and dry. Remove all dust, laitance, loose matter, oil, curing compound, form release agents, or other contaminants. Concrete should have a minimum strength grade of 25 MPa, as per AS 3600. Allow concrete to age 14-28 days, depending on thickness and the primer being used, ensuring proper moist-curing.
Primer: Required. Use SILCOR Primer BS for substrates with a maximum moisture content of 5%. For moisture content less than 10%, a different primer such as SILCOR Primer BW Clear or EPOCOTETM F100W Clear is specified.
Substrates: Compressed fibre cement sheet, metal, brick.
Surface prep: Ensure the substrate is structurally sound, clean, and dry. Remove all dust, loose matter, oil, and any other contaminants that could interfere with adhesion.
Primer: Required. SILCOR Primer BS is applied directly to these prepared surfaces to promote strong adhesion for SILCOR polyurethane membranes.
| Property | Value |
|---|---|
| Colour | Clear |
| Specific Gravity | 0.9-1.0 g / mL |
| Viscosity | 500 mPa.s |
| Flashpoint | 23 °C |
| Ignition Temperature | 425 °C |
| Drying Time @ 20°C | 30 - 60 minutes |
| Coverage | 0.3 kg/m² (0.3 litres/m²) |
| Shelf Life | 12 months (unopened cans) |
| Minimum Concrete Strength | 25 MPa |
| Concrete Age Before Priming | 14-28 days |
| Maximum Substrate Moisture Content | 5% |
Here are some common examples on where Silcor Primer BS used by our customers.
