Polyurethane sealants are a multi purpose low modulus (good for high movement) joint sealer. Often called construction sealant, pu sealant or modified silicone sealant. It's used for making expansion and weatherproof joints and seals in common construction materials. It can be used inside or out for multi purpose sealing and/or making expansion joints in precast concrete and tilt slab panels, general masonry, plasterboard and drylining installs, door and window installations, pipe and service duct sealing and any construction application where a flexible seal is required.
It's often used as sealer in horizontal and vertical butt or fillet (corner) joints in concrete, brick and block, rock, stone and general masonry, rendering and screeds, plasterboard, fibre cement sheeting, aluminium frames and fabrications etc.
It can expand and contract up to 50% of it's width so it's perfect for general and large joints between same or different building materials. Please refer to chart below for each brands joint movement capability. Each box comes with 4 nozzles. Each 4 pack comes with one nozzle.
Types and Differences of Polyurethane Sealants
There's a few key areas of focus when determining which polyurethane sealant is correct for your job and the differences between brands. Shore A Hardness rating is by far the most useful area to focus on. Poly Sealant with a shore a hardness rating of below 45 are generally classified as low modulus sealant. The shore hardness of polyurethane sealant ranges generally from 10 - 75.
The lower the number the softer the polyurethane is, the more pliable and elastic it is, giving it more flexibility and better recovery properties. Making it easier to caulk and thus, low shore a hardness polyurethanes are usually used as sealers or joint fillers. High shore a hardness ratings, anything over 30, increase the firmness or hardness of the polyurethane, reducing the elasticity but increasing the adhesion properties and reducing the cure time. Hardness ratings over 30 are generally referred to as FC polyurethane or fast cure polyurethane. Please see chart below for easy to read infographic to help determine which type of polyurethane is right for your application.
- Sikaflex Pro and Sikaflex Pro+
- Fulaflex 625 / 550
- Sellys Flexiseal
- Parchem PU25
- Soudal Multibond SMX25 Flex n Seal
- Bostik Seal n Flex 1 or Seal n Flex IQ
- Adheseal PU-15
Polyurethane Brand Comparison
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