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DOWSIL™ 791 Weatherproofing SealantVendor:
DOWSIL 791 Weatherproofing Sealant is a neutral-cure, medium-modulus silicone for keeping window perimeters, curtain wall joints and building façades weather-tight. It remains flexible as architectural joints move and is designed to withstand long-term outdoor exposure.Where to use DOWSIL 791Specify 791 for non-structural weathersealing around...- From $15.01
- From $15.01
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Sikaflex® Construction AP+ - WhiteVendor:
Sikaflex Construction AP+ is a one-component, non-sag polyurethane sealant for movement and connection joints in concrete, masonry and other compatible building materials. It accommodates ±25% joint movement to ASTM C 719 and is suited to internal and external façade and building-joint sealing. Where to...- $312.66
- $312.66
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Concrete Grey
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Bostik Seal 'N' Flex® FC P577 - WhiteVendor:
Bostik Seal 'N' Flex FC P577 is a one-component, high-modulus, fast-curing polyurethane sealant for construction, movement and trafficable joints. This product is supplied in 600ml sausage format. Bostik's official technical data sheet specifies ±25% movement capability; it is not Seal 'N' Flex One P390.Product...- From $239.40
- From $239.40
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Grey
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Black
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Bostik Seal 'N' Flex® FC P577 - WhiteVendor:
Bostik Seal 'N' Flex FC P577 is a one-component, high-modulus, fast-curing polyurethane sealant for construction, movement and trafficable joints. This product is supplied in 300ml cartridge format. Bostik's official technical data sheet specifies ±25% movement capability; it is not Seal 'N' Flex One P390.Product...
- From $266.22
- From $266.22
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Grey
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Bostik Seal 'N' Flex® One Plus P590 - WhiteVendor:
Bostik Seal 'N' Flex One Plus P590 is a high-movement polyurethane sealant for expansion and construction joints in precast panels, concrete, masonry and cladding. Its +100%/−50% movement capability and specified joint widths up to 80mm distinguish it from P390. This 300ml cartridge provides the...
- $239.40
- $239.40
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Grey
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Black
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Bostik Seal 'N' Flex® One Plus P590 - WhiteVendor:
Bostik Seal 'N' Flex One Plus P590 is a low-modulus polyurethane sealant for wide, high-movement construction and expansion joints in precast panels, concrete, masonry and cladding. Its +100%/−50% movement capability and suitability for specified joints up to 80mm make it the more demanding-joint option...
- From $239.40
$310.60- From $239.40
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Limestone
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SA Contractors Silicone Sealant - BlackVendor:Sealants AustralasiaSA Contractors Silicone Sealant is a fast-curing acetoxy silicone for general glazing, shopfronts, glass-to-aluminium sealing, sheet metal, signage and exterior weatherproofing on compatible substrates. It is a practical contractor silicone for standard glazing and fabrication work where quick skinning, strong adhesion and long-term UV...
- From $9.40
- From $9.40
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Translucent
Frequently Asked Questions
How do I choose a sealant for façade work?
Match the sealant to the joint: polyurethane like Bostik Seal-N-Flex P390 and P590 for high-movement construction joints, Dowsil 791 silicone for curtain-wall perimeters and expansion joints, RLA Flex Pro MS for glass, timber, and stone.
Which sealant do I use for a curtain-wall perimeter joint?
Dowsil 791 handles curtain-wall perimeter and expansion joints up to ±50% movement. It is a neutral-cure silicone that bonds to coated glass, galvanised steel, and masonry without a primer on most non-porous surfaces. Do not use it as a structural sealant.
Can I use Bostik Seal-N-Flex around aluminium window frames?
Yes, for movement joints in aluminium window and cladding systems, not for sealing glass to frame. P390 handles ±50% movement and P590 handles +100%/-50%. Both are low-modulus polyurethanes. Do not use them for glazing applications or in trafficable joints.
What is the difference between polyurethane and MS polymer sealants here?
Polyurethanes like P390, P590, and Sikaflex Construction AP+ handle high movement on concrete, brickwork, and cladding. MS polymer like RLA Flex Pro MS bonds to glass and timber, and will not stain stone. Check each product's movement rating and substrate limits.
Can I paint over these sealants?
P390, P590, and Sikaflex Construction AP+ can be painted after 7 days. Dowsil 791 and SA Contractors silicone cannot be painted. RLA Flex Pro MS can be painted after full cure, but test first.
Do I need a primer before applying these sealants?
It depends on the substrate. P390 and P590 stick to clean concrete, mortar, and bare aluminium without primer. For porous substrates in immersed use, prime with Bostik N49. For non-porous metals and plastics, prime with Bostik N40. Dowsil 791 bonds unprimed to most surfaces.