Sikasil 825 Silicone

Sikasil® 825 Silicone is a professional-grade construction and glazing sealant designed for demanding internal and external applications. It delivers excellent adhesion, long-term weather resistance, and a clean, durable finish, making it ideal for large-scale building, façade, and glazing projects.

Usage

Sikasil® 825 is suitable for perimeter pointing around uPVC, timber, and powder-coated aluminium window and door frames, both internally and externally. It can also be used for sealing and bonding uPVC trims, plastic components, and soft metals such as lead, copper, and zinc. The sealant is ideal for weather and joint sealing to pre-formed panels and curtain walling, as well as for glazing applications including glass-to-glass and glass-to-aluminium sealing. Additional uses include parapet and roof weather sealing, expansion joints, bedding and sealing insulated glass units, and sealing precast concrete and masonry products such as brick, natural stone, and terracotta.

Advantages

This high-performance silicone offers excellent tooling characteristics and slow skinning time, making it particularly well suited to large-scale construction and glazing applications. Its high-viscosity, non-slump formulation allows precise application on vertical joints without sagging. Sikasil® 825 provides outstanding adhesion to most common construction materials, including glass, metals, plastics, wood (painted or unpainted), uPVC, and polycarbonate. It also delivers excellent long-term external weathering performance and, once fully cured, is resistant to fumed hydrogen peroxide and fumed formaldehyde.

Packaging & Colour Options

Sikasil® 825 Silicone is available in: 380ml cartridges 400ml foil packs 600ml foil packs It is supplied in a wide range of colours, including White, Black, Mid Grey, Dark Grey, Brick Red, Brown, Buff, Beige, Anthracite, Dark Anthracite (RAL 7016), Magnolia, Portland Stone, and Limestone White. Please note: not all colours are available in all sizes.

FAQs

Is Sikasil® 825 suitable for external use?

Yes, it offers excellent long-term weather resistance and is designed for demanding external construction and glazing applications.

Can Sikasil® 825 be used on masonry and concrete?

Yes, it is ideal for precast concrete and masonry surfaces, including brick, natural stone, and terracotta.

Is Sikasil® 825 suitable for glazing applications?

Yes, it is suitable for glass-to-glass sealing, glass-to-aluminium sealing, and bedding insulated glass units.

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At JJ Building Materials, we're committed to supplying quality building products at competitive prices, backed by the service and expertise you'd expect from an established independent merchant. Whether you're a trade professional managing large-scale projects or a homeowner taking on a DIY renovation, we're here to help you find the right products for the job.

As part of the JJ Roofing Supplies Group, we build on decades of experience supplying construction materials across the UK. We've expanded beyond roofing to offer a growing range of building materials, including timber, insulation, landscaping products, plumbing supplies, flooring, doors, bricks, fencing, garden buildings and much more – all available to order online with nationwide delivery.

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Every order is personally reviewed by our experienced team to ensure everything is correct before dispatch. We offer delivery from as little as the next working day on selected products, so please refer to the dark blue Estimated Delivery box above for the expected delivery timeframe for this item.

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Roof Tiles & Fittings:

We recommend ordering an additional 10% of roof tiles to allow for any breakages that may occur during delivery or handling. Roof tiles are naturally fragile, and having a few extra on site helps prevent delays and ensures your roofing project can be completed without interruption.