Product form

Dowsil 791 - Weatherproof Silicone Sealant

£9.39Incl. VAT

Dowsil 791 is a high-performance low-modulus, neutral-cure silicone sealant developed for exterior weather-sealing applications. Engineered to deliver durable, flexible joints,...

SKU: 4024907/C05


36 products in stock Show extra info for delivery time


    • Same day shipping on orders before 14:00*

    • Discounted Trade Rates

    • Premium Products

    How much Sealant do I need? View coverage table

    Product Details

    • Description

      Dowsil 791 is a high-performance low-modulus, neutral-cure silicone sealant developed for exterior weather-sealing applications.

      Engineered to deliver durable, flexible joints, it provides exceptional adhesion to a wide variety of building materials including glass, anodised aluminium, steel, brick, and painted surfaces—without the need for a primer in most cases.

      Its ±50 % movement capability and long-term resistance to weathering, UV, and ozone make it the professional choice for curtain walling, façade joints, and window perimeters.

      Non-corrosive and low-odour, Dowsil 791 cures at room temperature to form a tough, elastic seal that accommodates structural movement and vibration.

      Whether used in new construction or refurbishment, it ensures a clean, watertight finish that stands up to years of exposure, making it one of the most reliable weatherproofing sealants on the market.

    • Benefits

      • Low-modulus neutral-cure silicone providing ±50 % joint movement capability
      • Excellent adhesion to glass, aluminium, masonry, and painted surfaces
      • Ideal for curtain walls, glazing, and window perimeter joints
      • Outstanding resistance to UV, ozone, and extreme weather conditions
      • Maintains long-term flexibility without shrinkage or cracking
    • How to Apply

      1. Surface Preparation

      • Non-porous substrates (e.g. glass, aluminium, metals): Clean with Dowsil R-40 Universal Cleaner or another approved solvent on an oil- and lint-free cloth; wipe dry immediately.
      • Porous materials (e.g. concrete, brick, stone): Remove loose particles and dust by wire-brushing or other mechanical methods. Ensure surfaces are clean, dry, and sound.

      2. Masking - Use masking tape along joint edges to achieve clean lines and prevent spreading onto adjacent finishes.

      3. Application - Cut the nozzle to the required joint width. Using a suitable caulking gun, apply a continuous bead of Dowsil 791, ensuring full contact with both joint faces.

      4. Tooling - Tool immediately after gunning to compress the sealant into the joint and create a smooth, concave profile. Remove masking tape before skin forms.

    © 2025 The Sealant Shop