11
GCP SILCOR Primer BS 17kg polyurethane primer for SILCOR waterproofing membranes on dry construction substrates.
GCP SILCOR Primer BS 17kg polyurethane primer for SILCOR waterproofing membranes on dry construction substrates.

SILCOR® Primer BS

Fast-drying single-pack polyurethane primer for dry prepared substrates before compatible SILCOR waterproofing membranes.

Vendor: GCP
SKU: PRIMESILCORBS/17
Availability: In Stock
$299.29
$299.29
Prices do not include GST
Guaranteed safe checkout
  • Apple Pay
  • Google Pay
  • Mastercard
  • Shop Pay
  • Visa
  • Secure SSL encrypted checkout
  • Fast, tracked shipping
  • Easy returns & support
Shipping & Delivery

Flat-rate shipping $17.95 + GST (metro and standard zones). Excludes remote/regional/high-cost postcodes and certain items (DG, oversized, long-length, or bagged products 15 kg+). If your order includes any of these, we will contact you to arrange additional freight charges. Online purchases only.

Download Product Data

Download TDS Download SDS
Description  

SILCOR® Primer BS is GCP's fast-drying, single-pack modified polyurethane primer for compatible SILCOR polyurethane waterproofing membranes. It is designed for dry, prepared construction substrates and provides the bond between the substrate and the liquid-applied membrane.

Where SILCOR Primer BS fits

GCP specifies Primer BS across SILCOR polyurethane systems on suitable rigid substrates including concrete and masonry, cement render, shotcrete, precast concrete, compressed fibre cement sheet, metal and brick.

Moisture limit

Use Primer BS only where substrate moisture is 5% or less. For prepared concrete or masonry above that limit, current SILCOR system guidance nominates EPOCOTE™ F100W Clear for the 5.0% to 6.9% moisture range. Always follow the membrane-specific PDS.

Numbers that matter

  • Single pack: no resin/hardener mixing.
  • Minimum application rate: approximately 0.3 kg/m², depending on substrate porosity and condition.
  • Tack-free at 25°C: typically 1 to 2 hours under GCP's stated conditions.
  • Maximum recoat window at 25°C: 24 hours.
  • Application temperature: 5°C to 35°C.

Preparation and application

Substrates must be structurally sound, smooth, clean and dry. Remove dust, laitance, loose material, oil, curing compounds and release agents before priming. Apply by brush, roller or spray and allow the primer to become tack-free before applying the specified SILCOR membrane.

If the primer remains uncoated beyond the current GCP recoat limits, follow the GCP preparation and repriming procedure rather than simply coating over the aged primer.

Compatible Adheseal SILCOR membranes

Use Primer BS where specified with SILCOR 560 HB, SILCOR 560 HB LVOC, SILCOR 575 LB and SILCOR 580.

Browse the complete GCP Applied Technologies waterproofing range.

Common Questions  

What is SILCOR Primer BS used for?
It primes dry rigid substrates before SILCOR polyurethane and polyurea membranes.

How fast does it dry?
About 20–30 minutes at 20°C.

What coverage should I allow?
About 0.15kg/m², or 0.3kg/m² and above on very porous concrete.

How long can the primer sit before membrane application?
Only prime areas that can be membrane-coated within 6 hours.

Uses & Benefits  
Fast-drying single-pack modified polyurethane primer for SILCOR polyurethane and polyurea membranes. Used on dry rigid construction substrates with up to 5% moisture content. Typical application rate is about 0.15kg/m², increasing to 0.3kg/m² or more on very porous concrete. Drying time is about 20–30 minutes at 20°C. Adhesion to concrete is greater than 1.5MPa to ASTM D4541.
How To Apply  
Prepare surfaces so they are structurally sound, smooth, clean and dry. Allow concrete at least 28 days cure and render at least 7 days. Apply one coat directly from the container by brush, roller or spray. Allow about 0.15kg/m², increasing to 0.3kg/m² or more on very porous concrete. Allow the primer to become tack-free before membrane application. Only prime the area that can be membrane-coated within 6 hours.
Limitations and Safety Info  
Use on substrates with a maximum moisture content of 5%. Prime only areas that will receive membrane within 6 hours. If the primed area is not coated within 6 hours, follow GCP's cleaning and reprime procedure. If left uncoated for more than 72 hours, fully remove the primer by diamond grinding and reprime. Prepare concrete, render and other substrates to the cure and cleanliness requirements in the current TDS.
Suitable Substrates  
  • Concrete masonry and in-situ concrete.
  • Precast concrete and shotcrete.
  • Cement render and lightweight concrete.
  • Compressed fibre-cement sheet.
  • Prepared metal.
  • Brick.

SILCOR® Primer BS Physical Properties

SILCOR® Primer BS Physical Properties
Property Value
Specific Gravity 0.9-1.0 g / mL
Viscosity 500 mPa.s
Flash Point 23 °C
Ignition Temperature 425 °C
Full Cure 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%
Water Resistance Excellent

SILCOR® Primer BS - Use Cases

Here are some common examples on where SILCOR® Primer BS used by our customers.

Civil Construction

Prepare Trafficable Decking Surfaces

Priming concrete car park decks or elevated walkways before applying heavy-duty trafficable polyurethane membranes.

Provides the essential bond for high-performance trafficable membranes like SILCOR 580, ensuring system durability on exposed surfaces.

  • Strong physical bond to concrete
  • Prepares for SILCOR 580 membrane
  • Max 5% substrate moisture
  • Coverage 0.3 kg/m²

Waterproofing

Prime Rigid Substrates for PU

Preparing concrete, masonry, or CFC sheet for subsequent application of SILCOR polyurethane-based waterproofing membranes.

Ensures strong adhesion and forms a robust physical bond between various rigid construction substrates and SILCOR PU membranes.

  • Single-pack modified polyurethane
  • Strong physical bond to concrete
  • Coverage 0.3 kg/m²
  • Max 5% substrate moisture

Roofing

Existing Roof Membrane Priming

When re-waterproofing dry concrete roofs or tiled areas with existing polyurethane membranes before new Silcor application.

Ensures robust adhesion for Silcor polyurethane membranes on prepared, dry substrates, crucial for long-term waterproofing performance.

  • For dry substrates max 5% moisture
  • 30-60 minutes drying time
  • Bonds to existing polyurethane membrane
  • Coverage 0.3 kg/m²

Roofing

CFC Sheet Waterproofing Prep

Priming compressed fibre cement sheets on external balconies or wet areas before Silcor membrane application.

Its penetrating polyurethane resin system creates a strong, fast-drying bond on porous CFC sheets for Silcor membrane adhesion.

  • Bonds to compressed fibre cement
  • 30-60 minutes drying time
  • For dry substrates max 5% moisture
  • Coverage 0.3 kg/m²

Waterproofing

Fast Membrane Application, Cold

When applying SILCOR polyurethane membranes in cooler temperatures or with tight project deadlines.

Its rapid drying time and proven adhesion in cold conditions minimise delays, allowing quicker membrane application even when interrupted by weather.

  • 30-60 minute drying time
  • Adhesion in cold weather
  • Water-resistant coating
  • Single-pack PU resin system

Alternative Products

Vendor
Example product title
$299.29
$299.29
Vendor
Example product title
$299.29
$299.29
Vendor
Example product title
$299.29
$299.29
Vendor
Example product title
$299.29
$299.29
Vendor
Example product title
$299.29
$299.29
Vendor
Example product title
$299.29
$299.29

Need Help with SILCOR® Primer BS?

Need more information about this product? Hit the button below and reach out to one of our experts now.

Get In Contact
Recently Viewed Products