How to apply sealant using a silicone gun

How to apply sealant using a silicone gun

Sealant is an essential line of defence to stave off leaks and spills and ultimately keep moisture out of places you don’t want it to go like into gaps between walls and floors. Over time you may find that the sealant around your home needs replacing and good news is that this is a job you can easily complete yourself. With our helpful step-by-step guide we can show you how to achieve a clean and professional finish applying sealant without too much stress and for relatively little cost too.

The most common places you will find sealant around your home will be anywhere that water is accessible - so think bathrooms, kitchens and water closets. Sealant comes in several varieties and colours depending on its intended purpose and placement so it is important to get the right sealant for the job as it is not a one type suits all kinda product.

The tools you will need when applying sealant

  • Sealant (most often a type of silicone or caulk in tube form, the type depends on the intended job so read the product information to determine which product you need)
  • Sealant strip-out tool (if you are removing and replacing old sealant)
  • Sealant eater (an optional chemical sealant remover for hard to remove sealant)
  • Degreaser or spirit cleaner (for prepping the area before applying the new sealant)
  • Sealant gun (to help you apply the tube sealant)
  • Sharp blade (utility knife etc)
  • Clean cloths (or clean rags like an old t-shirt)
  • Paper towel / Kitchen roll (for cleaning up excess sealant)
  • Protective gloves (latex or vinyl, something that will allow good grip and the ability to use your fingers when finishing off)
  • Spray bottle with soapy water (tap water with some dish soap will make cleanup and finishing the sealant edge a lot less messy)
  • Sealant finishing tool (also known as a profiling tool or sealant smoother - optional)

Step-by-step guide on how to easily apply sealant and achieve a smooth neat finish

1. Remove old sealant
If you are going to be resealing an already sealed area then you will need to remove the old sealant first, this is best achieved using a sealant strip out tool and the use of some sealant eater (if your old sealant is particularly hard to remove). You can remove old sealant using a sharp blade like a utility knife if you’re in a pinch and don’t have the strip-out tool but you run the risk of damaging nearby surfaces with the blade if you’re not careful so we recommend the strip-out tool if you have one.

Closeup of hand using a yellow seal/silicone removal tool.

2. Clean and dry surfaces
After stripping out the old sealant be sure to wipe down the area using a clean cloth and a small amount of degreaser or spirit cleaner. This will ensure the area to be sealed is dust free and there are no bumps or obstructions left over from the old sealant which might hinder you achieving a neat application. Once you have wiped down the area, allow some time for it to dry as you don’t want to be sealing in any unwanted moisture.

Closeup of a hand wearing a peppermint coloured rubber glove using a yellow kitchen sponge to wash and clean tiles

3. Fill the bathtub
If you’re sealing around the edge of a bath then fill the bath up with water beforehand. The reason you want to do this is so the bath is weighed down (as it would be when in use) sealing around a filled bath will prevent the sealant from overstretching and pulling away when the bath is in use later on.

Bathtub being filled with water

4. Put on gloves
As some sealants can irritate the skin it’s recommended that you wear protective gloves so now is the time to put these on. For the application process any protective gloves of your choice are suitable.

Hands putting on surgical gloves

5. Assemble your sealant gun
Using your blade, cut off the end of the sealant tube and then immediately screw on the nozzle (tubes of sealant normally come with a nozzle, but extra nozzles can also be purchased separately too). You’ll want to cut the tip of the nozzle and aim for something close to a 45° angle. Ensure that the opening you are cutting is slightly larger than the gap you are sealing. If unsure, cut it on the smaller side, check and then recut if needed. Remember you can make a cut hole bigger but never smaller! So start small and work your way up if unsure.

Green silicone gun, utility knife and tube of silicone sealant with a white tiled background

6. Apply sealant
Carefully place the tube of sealant inside the sealant gun and gently squeeze the trigger to get the sealant moving into position. The nozzle is somewhat transparent so you should easily be able to see the sealant slowly fill the nozzle. The best position and angle to apply the sealant is at 45°. Without rushing, in a relaxed manner gently pull the trigger to distribute the silicone while at the same time pulling the gun towards yourself away from the starting point of the area you are sealing. If you have plenty of sealant and would rather do a practice run beforehand you can try running a bead of sealant on some scrap cardboard or paper. Practicing first is a good way to get a feel for the sealant gun if this is your first time using one.

To apply the sealant, start at a corner or edge, keep the gun at a 45° angle and pull the gun slowly and steadily towards yourself while applying pressure to the trigger. Once you reach the end of the bead, release the handle and press the button or lever at the back of the gun. Doing this will release the pressure so the sealant stops flowing.

Continue this process around all areas that need sealing, you may find you need to stop and start a few times (depending on what you are sealing etc). Don’t worry though as you’ll be able to neaten up your work afterwards. Slow and steady is key.

Closeup of man wearing yellow work gloves, using a green silicone gun to apply sealant around a bathtub

7. Finish and cleanup edges
Once you have applied the silicone it is time to finish the seal. Finishing basically means neatening up the beading you have just applied so that the edges are nice and tidy. Depending on your choice of finishing method you will generally be completing your sealing job by using a sealant finishing tool or going for the trusty finger and soapy water method. You can read about the different finishing methods below.

Closeup of male hand using a sealant finishing tool to smooth out the sealant around a bathtub

How to finish the edge of your sealant using just your finger and some soapy water

After you have run your bead of silicone you will want to take your spray bottle of lightly soapy water and then gently spray over the freshly sealed area and also your fingertips (we recommend wearing protective close fit rubber gloves to avoid any irritation from the sealant if you should have sensitive skin). Using your finger tip, start in a corner or at an edge and gently press your finger to the bead of silicone and smoothly drag it along the seal. This action will smooth out the seal and remove any excess sealant leaving you with a nice neat finish. Spraying the area and your finger with soapy water prevents the silicone from sticking to surfaces where you don’t want it to, this includes your fingers. Simply wipe the excess sealant onto some kitchen roll to discard.

The benefit about using the soapy water and finger method is you have absolute control with your finger and if you make any mistakes or light bumps you can easily spray the area again and reapply your finger gently to smooth it out. This method is popular with tradespeople as it requires no special tools or advanced prep work.

How to finish the edge of your sealant using a sealant finishing tool also known as a sealant smoother

Finishing with silicone and caulk can be a bit of a finicky process, especially if you don’t have a steady hand. However there are some nifty sealant smoother tools on the market that allow you to create a clean and sleek finish to your sealant and all with minimal effort on your part. Using your finishing tool, start at a corner or edge and run the tool along the sealant as you would your finger if you were using the soapy water method. The tool will then smooth out the sealant and gather any excess product for you to wipe off onto some kitchen roll.

Finishing tools are brilliant as they can give several options for how you want your seal to look. Some finishing tools allow for a convex, concave or straight edge and can also allow for varying widths which is especially handy if you’re wanting to seal a wider than normal gap.

We hope you have found this article useful and now have the confidence to tackle your own sealing or resealing project at home! We are proud to have a variety of tools and products available online for you to complete your own weekend DIY projects. So whether it be resealing your bathroom, replacing your toilet seat or even getting your garden summer ready we are here to support you on your DIYing endeavours.



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