Soudal Silirub N Low Modulus Neutral Cure Silicone 310ml

Soudal Silirub N is a one-component, low modulus neutral cure silicone sealant designed for the window installation and construction trades. As a window silicone sealant, it is one of the most widely used products in the glazing sector, trusted by window fitters and installers across the UK for its reliable adhesion, permanent flexibility, and long-term colour stability. It stays elastic after curing, which is exactly what you need in joints that move with thermal expansion and building settlement.

Low modulus silicone is a specific formulation that places less stress on the joint faces as the sealant expands and contracts. This matters particularly on UPVC frames, where a standard high modulus silicone can cause distortion or delamination over time. Silirub N applies consistently from a standard 310ml cartridge using either a manual or pneumatic caulking gun, making it practical for all installation volumes from single windows to full site programmes.

Where Soudal Silirub N Gets Used

Silirub N is specified for building and construction joints, perimeter sealing around window and door frames, expansion joints between different building materials, and sealing between treated timber and glass. It bonds well to glass, PVC, painted surfaces, and most common building substrates without the need for primers on the majority of clean, dry surfaces.

The neutral cure chemistry means it does not release acetic acid during curing, so it is safe to use adjacent to metals such as zinc, lead, copper, and brass where an acetoxy silicone would cause corrosion. It also eliminates the vinegar smell that tradespeople and site visitors tend to find less than welcoming.

Colour Options and UV Stability

Silirub N is available in five colours: white, clear, black, anthracite, and teak. All are UV-resistant and maintain their colour over time without chalking or significant fading. The teak option is particularly useful for timber-effect UPVC profiles, where a white or grey sealant would look out of place. Colour consistency from cartridge to cartridge is reliable, which matters when you are finishing multiple windows on the same elevation.

As a window silicone sealant, Silirub N performs consistently across a wide application temperature range of plus five to plus thirty-five degrees Celsius, so it is usable through most of the UK working year without issue. Surface finish is achieved using soapy water or Soudal Smoothening Liquid before the sealant skins over. Clean up uncured product with white spirit immediately after application.

One point worth noting: Silirub N is not formulated for structural glazing or the installation of double-glazed sealed units where the sealant comes into contact with the primary warm-edge spacer seal or the PVB film in laminated security glass. For those applications, Soudal Silirub PV or Silirub 2 are the correct choices. Using the right product in the right place keeps you on the right side of warranty claims and glass unit longevity.