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Dowsil 791 Weatherproofing SealantVendor:
Dowsil 791 is a high-performance, one-part neutral-cure silicone weatherproofing sealant formulated for expansion, connection, and perimeter joints in curtain wall and façade applications. With ±50% movement capability and excellent UV/weather resistance, it bonds strongly to glass, aluminium, masonry, and metal substrates without primer on most surfaces. Available in multiple colours, it’s a go-to solution for glazing professionals and façade contractors.- From $14.97
- From $14.97
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Sikaflex Construction AP+ Polyurethane SealantVendor:
Use Sikaflex Construction AP for reliable, elastic sealing of movement and connection joints, particularly on porous substrates. Its ±25% movement capability, non-sag application, and paintability ensure durable, professional finishes for facades and general construction.- $311.80
- $311.80
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Bostik Seal 'N' Flex One P390 Polyurethane Sealant 600ml - BlackVendor:
Use Bostik Seal N Flex One P390 for reliable sealing of construction and expansion joints that demand ±50% movement. It's a low modulus, one-component polyurethane sealant, acoustic rated and approved for potable water contact, preventing joint failure in dynamic environments.- From $322.60
- From $322.60
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Black
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Grey
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White
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Bostik Seal 'N' Flex One P390 Polyurethane Sealant 300ml - GreyVendor:
Use Bostik Seal N Flex One P390 for reliable sealing of construction and expansion joints that demand ±50% movement. It's a low modulus, one-component polyurethane sealant, acoustic rated and approved for potable water contact, preventing joint failure in dynamic environments.
- $355.80
- $355.80
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Grey
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Bostik Seal ‘N’ Flex One Plus P590 Polyurethane Sealant 300mlVendor:
Use Bostik Seal 'N' Flex One Plus P590 for construction and expansion joints needing high movement capability. It offers +100% / -50% joint movement with bubble-free curing and AS/NZS 4020:2018 potable water certification.
- $238.80
- $238.80
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Bostik Seal ‘N’ Flex One Plus P590 Polyurethane Sealant 600mlVendor:
Use Bostik Seal 'N' Flex One Plus P590 for construction and expansion joints needing high movement capability. It offers +100% / -50% joint movement with bubble-free curing and AS/NZS 4020:2018 potable water certification.
- From $322.60
$310.60- From $322.60
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SA Contractors Silicone SealantVendor:Sealants AustralasiaUse SA Contractors Silicone for general purpose glazing and sealing applications, offering excellent UV and weather resistance. It handles joint movement up to ±25% and skins in 5-10 minutes, making it a reliable choice for exposed work.
- From $9.37
- From $9.37
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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.