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Ensuring optimal adhesion and performance of SILCOR polyurethane-based waterproofing membranes requires a specialised primer. SILCOR Primer BS provides a strong physical bond and promotes adhesion to rigid substrates, even in cold weather. This prepares the surface, guaranteeing the membrane system performs as intended.
SILCOR Primer BS was developed as a fast-drying, single-pack, modified polyurethane primer to prepare dry, rigid substrates with a maximum moisture content of 5% for all SILCOR polyurethane-based membranes. Its formulation delivers robust physical adhesion, crucial for the long-term integrity of the waterproofing system, especially on diverse construction surfaces.
SILCOR Primer BS is applied directly from its container using a brush, roller, or spray. The treated surface must become tack-free before the SILCOR waterproofing membrane is applied. Strict adherence to the 24-hour recoat window is crucial; if the membrane is not applied within this timeframe, the primed area must first be wiped with Xylene, then lightly reprimed with SILCOR Primer BS once the Xylene has dried. If more than 72 hours pass without membrane application, the original primer must be fully removed by diamond grinding and the surface reprimed to ensure adequate adhesion.
SILCOR Primer BS excels in critical waterproofing preparation for various rigid construction substrates. It is frequently specified in Roofing — concrete roofs, membrane-covered tiled projects as a primer for existing polyurethane membranes, ensuring renewed systems achieve their full bond strength. It is also used as a foundational primer for new or refurbished surfaces in Car parks, high traffic areas, and external above-ground structures, providing the necessary adhesion for trafficable waterproofing membranes.
In applications such as an Elevated Walkway, SILCOR Primer BS functions as the essential first step. It is applied to the prepared substrate to establish a strong bond before the application of the primary waterproofing layer, such as SILCOR 580 trafficable waterproofing membrane. This foundational priming ensures the membrane system achieves its specified performance and durability.
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.
