Illbruck FS125 Product Image

What is Illbruck FS125?

Illbruck FS125 is a one-part, neutral curing, low modulus, low odour silicone sealant suitable for perimeter joint sealing applications with high movement capability. It has excellent primerless adhesion to multiple surfaces including masonry, brick, aluminium, PVC-U, polycarbonate, polyacrylate, wood, painted wood, glass and glazed surfaces.

What applications can Illbruck FS125 be used for?

FS125 is ideal for use in expansion &curtain wall joints, perimeter joints around windows or doors, panel joints between most common substrates, heel and toe beads, polycarbonate glazing and other general joint sealing applications.

Not suitable for some substrates such as neoprene, butyl rubber, EPDM, bituminous or tar containing surfaces. Contact with bituminous or tar containing surfaces can lead to discolouration and failing adhesion. Not suitable for trafficable joints or areas subject to abrasion. Not suitable for over painting. For safe sealing on natural stone use FA870/ FA880. On other sensitive substrates test first.

Safety data sheet must be read and understood before use.

What are the benefits of using FS125?

  • Meets the requirements of EN ISO 11600 G&F 25LM
  • High movement capability
  • Long-term resistance to weathering, ageing and extra UV protection
  • Low modulus formulation ensures minimum stress at joint faces
  • Neutral cure: low odour
  • Modern colour range in low sheen finish
  • Easy to tool into place and smooth off

Our team are always on hand to provide technical product and application support.

For technical advice, or to place an order either call Tom Newton on 0044 (0) 7789 – 516858 , email or get in touch via our contact form. 

Check out this interesting case study ‘London Landmark revitalised with help from Illbruck’ using FS125 from Window News here.



FS125 Digital Colour Card [PDF]

Download the digital colour card here as a point of reference for silicone shades.


FS125 Technical Data Sheet [PDF]

Download the Technical Data Sheet.


FS125 Safety Data Sheet [PDF]

Download the Safety Data Sheet here.


FS125 Declaration of Performance [PDF]

Download the DoP here.