The one thing you can rely on with a British summer is its unpredictability. That said, when warmer, drier weather does arrive, it signals a busy period for the fenestration sector. Installation schedules fill quickly as homeowners take advantage of the conditions to replace or upgrade windows and doors.
With energy costs still a concern and growing awareness around heat loss and carbon reduction, improving the building envelope remains a popular investment. While glazing and frame choice often take centre stage, sealants play a crucial role in how well an installation performs over time. Choosing the right product helps ensure not just a clean finish, but long-term durability and weather resistance.
Arbosil LM silicone sealant has earned a strong reputation within the fenestration industry, and this article explores what sets it apart, along with its expanded colour range designed to suit modern window profiles and interior trends.
Understanding what Arbosil LM silicone sealant is
Arbosil LM is a single-component, neutral cure silicone sealant and is one of the most widely specified products in its category. Unlike acetoxy silicones, which release acidic by-products during curing, its neutral cure formulation produces very little odour. This makes it more comfortable to apply and suitable for use in occupied buildings, including homes, offices, and active construction sites.
Curing begins as soon as the sealant is exposed to moisture in the air, with no requirement for heat, UV light, or additional curing agents. As a low modulus silicone, Arbosil LM forms a highly elastic rubber seal once cured, allowing it to accommodate movement without losing adhesion. This makes it particularly well suited to applications such as perimeter sealing around PVCu frames, glazing, insulating glass units, expansion joints, and remedial glazing work.
Why installers continue to choose Arbosil LM silicone sealant
Arbosil LM has remained popular because it offers clear advantages for both installers and long-term building performance.
It is available in 14 colours, including translucent, white, black, grey, light grey, anthracite, brown, buff, dark bronze, portland, rustic red, magnolia, and RAL shades 7016 and 7022. This wide selection allows the sealant to blend seamlessly with modern frame finishes and contemporary glazing designs. Combined with resistance to many dilute acids and alkalis commonly found in cleaning products, it helps maintain appearance with minimal maintenance over time. Its expected service life of over 25 years aligns well with the lifespan of modern glazed units.
From an application perspective, Arbosil LM is designed with practicality in mind. When stored correctly in unopened packaging, it has a shelf life of up to 12 months. It can also be applied in temperatures ranging from +5°C to +40°C, making it suitable for use throughout the year in UK conditions.
The sealant forms a skin in approximately 10 minutes and cures at a rate of around 2mm per 24 hours at 20°C and 65% relative humidity.
Proven performance where it matters most
Sealant performance is critical for reducing call-backs and avoiding costly warranty issues. Arbosil LM is engineered to deliver consistent results over the long term.
With a Shore A hardness of 30, it achieves a balance between strength and flexibility. This allows it to resist abrasion, impact, and weathering while accommodating significant joint movement. It can handle up to 50% movement in butt joints under tension and compression, and up to 100% movement in lap joints under shear.
Its UV resistance ensures the seal retains elasticity and durability across a wide temperature range, from -40°C to +120°C. This exceeds the demands of typical UK weather and provides additional resilience in extreme conditions, including fire exposure.
Achieving the best results on site
To get the full benefit of Arbosil LM, correct joint preparation is essential. Surfaces should be clean, dry, and free from dust, grease, or other contaminants. Appropriate cleaning products should be used, and in some cases, a compatible primer may be required depending on the substrate. Technical advice should always be sought where there is uncertainty.
Where necessary, a joint filler such as closed-cell polyethylene foam should be installed to achieve the correct joint dimensions. Application should be carried out using a suitable caulking gun, and all preparation and installation steps should follow BS 8000-16:1997+A1:2010, the British Standard for sealing joints in buildings.
Arbosil LM is not recommended for overpainting, use in glass wall assemblies, or application against natural stone.
By combining careful preparation with a proven sealant, installers can deliver window and door installations that perform reliably and look good for decades.
