How to Apply Silicone Sealant Neatly

Applying silicone sealant can be tricky – especially in small, tight joints around showers, sinks and kitchen benchtops. Whether you’re refreshing the seal in your bathroom or applying silicone to a kitchen sink, following a few golden rules can help you achieve a smooth, professional finish.

In this guide, we’ll show you how to apply silicone sealant neatly using the correct techniques and Soudal’s product range. Avoid the most common DIY mistakes and get long-lasting, mould-resistant results.

• Proper Surface Preparation: Always ensure that the surface is clean and free of debris before applying silicone sealant. Use a cleaner to remove old sealant, dust, and dirt for a stable, clean base.
• Choosing the Right Sealant: Select a sealant tailored to your project’s needs. For high-moisture areas like bathrooms and kitchens, it is recommended to use one with mould resistance and superior adhesion.
• Correct Nozzle and Profiling Tool: Cutting the nozzle at a 90° angle and using a profiling tool sized to the joint ensures smooth, controlled application. Using a nozzle that’s too small or at a 45° angle can lead to poor control.
• Smooth Application: Push the sealant into the joint rather than dragging it along. This ensures stronger adhesion and prevents air pockets. Work in short sections for a consistent, clean finish.
• Clean as You Go: Wipe your tools clean after each use to avoid debris that can disrupt the next pass, helping you achieve a professional finish with minimal mess.
• Avoid Common Mistakes: Don’t use masking tape or your finger to shape the sealant. Also, avoid shaping the sealant into a concave profile, using water and detergent, or sealing all three sides of a joint.

These best practices apply primarily to bathrooms and kitchens, but the principles are useful for any situation where you need to seal small joints.

• Remove any dust, old sealant, or loose material to ensure a clean, stable base.
• Use a solvent-based cleaner like Soudal’s Cleaner & Degreaser Spray to clean the joint area.

Use a sealant suited to your specific job:

• High modulus silicones are ideal where strong adhesion and rigidity are needed.
• Low modulus options allow more flexibility and are suited for movement joints.

Expert Tip: For bathrooms and wet areas, we recommend Pureseal Neutral Cure Sanitary Silicone – a high-quality, neutral cure silicone with excellent mould resistance.

• Select the smallest profiling tool that overlaps the joint by 2–3 mm on either side.
• This rule is especially important for joints at 90° angles.

• Always cut the nozzle straight across at 90°, not at an angle.
• The nozzle width should match the size of your chosen profiling tool.

• Push the sealant into the joint, rather than dragging it along. This ensures stronger adhesion and fills voids effectively.

• Silicone sealant should ideally bond to two surfaces only, not all three. This prevents cracking as the materials expand or contract.

• Use an adapter guide for even lines, especially on transverse joints.
• Work in short sections to maintain control.

• For internal corners, apply silicone upward first, then from left to right.
• This minimises overlap and ensures a cleaner finish.

• Wipe your tools clean with a paper towel after each use.
• This ensures your next pass is smooth and free of debris.

Avoid these common mistakes to ensure a long-lasting, professional seal:

• Don’t use masking tape – it can leave uneven edges and trap sealant.
• Don’t use your finger – it often results in inconsistent, messy finishes.
• Don’t shape sealant into a concave profile – it weakens the seal.
• Don’t use water and detergent – they interfere with curing and adhesion.
• Don’t cut the nozzle too small or at 45° – it reduces control.
• Don’t pull the bead along the joint – it leads to air pockets.
• Don’t seal all three sides of a joint – this creates rigid, failure-prone seals.

Applying silicone sealant doesn’t have to be messy or complicated. By using the correct tools, products, and techniques, you can achieve a professional-looking finish in kitchens, bathrooms, and beyond.

Explore our full range of silicone sealants and accessories for your next sealing project.