How to apply a silicone sealant

Applying silicone sealant is an essential skill for home improvement enthusiasts and professionals alike. Whether you're sealing around bathtubs, windows, or kitchen surfaces, silicone provides a durable, waterproof barrier that prevents leaks and enhances the longevity of your fixtures. 

In this guide, we’ll walk you through the step-by-step process for the best way to apply silicone sealant effectively, from selecting the right product to ensuring a clean, smooth finish. With a few handy tips and the right tools, you'll be sealing like a pro in no time! 

• Your chosen EVO-STIK sealant
• Caulking gun 
• Utility knife 
• Scraper 
• Mild detergent or rubbing alcohol 
• Protective gloves 
• Masking tape 
• Cloth

Optional:

• Smoothing tool
• Soapy water

Before you learn how to apply silicone sealant, thorough preparation is key to ensuring a long-lasting, clean seal. 

Ensure your hands are protected with gloves. Then, use your scraper or utility knife to carefully remove most of the old sealant bead. Start by cutting the top and bottom lines of the sealant along the whole length and then pull off the bead from the surface. 

Once the majority of sealant is removed, clean the area with a mild detergent or rubbing alcohol to eliminate any residue. It is essential to remove the residue so that your new sealant application can be as smooth and neat as possible. 

Non-porous surfaces should be degreased using white spirit or non-oily solvents before being cleaned and left to fully dry. Any wood surfaces should be painted before applying sealant. 

If you're working around sensitive surfaces or want a crisp, straight edge, apply masking tape along the edges where the sealant will go. 

Then, your final preparation is to ensure the room is well-ventilated, as silicone sealant can emit strong fumes during application. With everything properly prepped, you’ll be ready to apply the new sealant smoothly and effectively. 

Cut the nozzle according to the seal width you want - we recommend going slightly wider than the sealant gap and ensuring this is at a 45° angle. 

Using your utility knife or similar sharp object, cut the top of the cartridge being careful not to damage the thread, then screw the nozzle onto the cartridge. Insert the cartridge into the caulk gun and pull the trigger to extract the sealant. 

You'll want to start in a corner and work from one end to another. Place the nozzle at a 45° angle from the surface and slowly squeeze out the silicone sealant, maintaining constant pressure so the flow of silicone will be a consistent amount.

Good to know: If you can see small waves on the top of the sealant, the means it's overflowing and you have filled the gap between the surfaces. Total filling of the gap is the goal.

Don’t forget to push the locking metal tongue on the caulking gun to stop the flow of sealant when you end your application. 

Once your sealant is applied, you'll want to smooth out the silicone. You can use a damp piece of wood, a specially designed smoothing tool, or a finger dipped in soapy water to smooth out and shape the sealant. 

After your first time smoothing the sealant, excess product may collect - discard this. Then, lightly run your chosen smoothing tool over the sealant for a second time, applying almost zero pressure to leave a smooth, perfect finish.

Tip: You should avoid licking your finger to smooth sealant because it introduces bacteria from your saliva into the sealant, which can potentially lead to mould growth.

To ensure the longevity of your new sealant, leave it to dry for 24 hours, and ensure the space is well-ventilated. For those sealants that allow for a quicker drying time, the area can be ready to use in a shorter period. Refer to drying times for your specific product using its technical data sheet. 

That's it! In just six simple steps, you can remove old sealant in the joints and replace them with perfectly smooth, new sealant in no time. Safely. Easily. Just like a professional.