Silicone, Acrylic or PU? Choosing the Right Sealant

Sealants look alike in the cartridge, but they behave very differently once cured. Choosing the right type saves rework, stains and callbacks.

Silicone

• Best for: wet areas such as kitchens, bathrooms, sinks and shower screens, glazing, and joints that need to stay flexible.
• Strengths: very flexible, water-resistant, and good with temperature changes and UV. Sanitary grades contain fungicide against mould.
• Watch out: most silicones can't be painted over. Some types can stain natural stone, so use a sealant marked as suitable for stone.

Acrylic

• Best for: interior gaps and cracks around skirting, door and window frames, and wall and ceiling joints that will be painted.
• Strengths: paintable, easy to tool and clean up with water, and low cost.
• Watch out: less flexible and less water-resistant than silicone, so it isn't suitable for wet areas or joints with large movement.

Polyurethane (PU)

• Best for: expansion joints in concrete, flooring, facades and heavy-duty construction joints.
• Strengths: strong adhesion, tough and abrasion-resistant, and usually paintable.
• Watch out: needs good surface preparation, and some grades need a primer. Check UV resistance for exposed joints.

Tips for a lasting joint

• Surfaces should be clean, dry and free of old sealant, dust and grease.
• Use a backer rod in deep joints, so the sealant bonds to two sides, not three.
• Check the manufacturer's datasheet for curing time, temperature range and movement capability. For chemical products, ask us for the MSDS.

How Delight can help

Browse Sealants & Protective Coatings, Adhesives & Glues and Paint & Painting Supplies. Datasheets and MSDS are free on request. Request a quotation for project quantities.