If you’re thinking about recaulking around your windows, you may be wondering if removing the old sealant is a must. After all, you could simply make new joints over the old ones to save time and money.

Remove old caulking

Well, this isn’t such a great idea! If you want truly effective and beautiful-looking joints, you’ll want to take the time to remove the old caulking. On the other hand, when removing the old caulking is impossible because it would damage the structure, the only solution is to caulk over the old joints. However, these areas should only account for 5% of the structure, so removal of the old sealant should be feasible for 95% of the building.

Let’s get to the heart of the matter and find out how to remove the old exterior caulk around your windows.

1 – Start by gathering the right tools

Old caulking joints are sometimes hard to remove. They can become very hard after prolonged exposure to the elements and UV rays.

Gather together various knives and blades that can be used to cut into the old sealant and remove it from surfaces. In many cases, a putty knife, an electric knife and a utility knife with a retractable blade such an X-Acto will suffice.

You should also have long-nosed pliers on hand to help you remove the small pieces that will stick to the edges of your home or condo windows.

You should also have a cleaning product, a stiff-bristled brush and a clean, dry cloth. You’ll need these to properly prepare the edges of your windows for new seals.

Finally, if you have to work at heights, make sure you have safety equipment to protect you from falling.

2 – Separate old joints from surfaces

Choose the smoothest surface to start peeling off the old caulking. Place the corner of the putty knife blade under the old sealant, keeping it flat, then push the blade along the joint to separate it from the surface. Always hold your knife parallel to the joint line to work most effectively.

Envlever le calfeutrage de fenêtre

If the putty knife is not effective for the job, you can use the retractable blade knife or the electric knife. However, use caution with this type of blade, as you could injure yourself or damage surfaces.

3 – Remove all traces of old caulking

The sealant usually comes off in strips. If you are lucky, you can simply pull on the partially detached joint to remove it. However, some pieces may remain stuck to surfaces and must be removed manually.

Use long-nosed pliers to grip them securely.

4 – Properly clean the surface to be caulked

When the old caulking is completely removed, carefully scrub the area with a stiff-bristle brush and a cleaning product that will not damage the finish of your surfaces.

clean joints with solvant calfeutrage Apex

Once done, wipe with a clean cloth. The area must be completely clean, dry and free of all grease, dirt and cleaners before you start the new joints.



Your caulk is polyurethane:

When the old caulk is polyurethane, you can expect to work pretty hard to properly remove it. Choosing the right tool to remove the caulk is essential. The best caulk removal trick we know and use, is to work with an electric knife. Despite the assistance this tool provides in removing caulk, it is normally much more time-consuming and difficult to remove polyurethane caulk.


Your caulk is thermoplastic:

When you need to remove window caulking and it is made of thermoplastic, also known as Flextra, your task is simplified. You can easily use pliers to remove the sealant from the surface to which it was applied. However, if you have to remove old, dark thermoplastic caulk, such as black or dark brown, it is important to do it on a day that is not too hot.

Thermoplastic caulk is very difficult, and sometimes impossible to remove on hot summer days, and it is even worse when it is dark in color. This type of caulk tends to melt during hot weather and could stain your surfaces. Choose a cool day to remove the thermoplastic caulk from your doors and windows. 


Your caulk is acrylic-based:

This time, you’re really out of luck if you have to remove acrylic-based caulk. This is the most difficult caulk to remove and you will need the right tools: A heat gun and an electric knife. You will also need a lot of patience and time on your hands. Be advised that it is almost impossible to remove acrylic-based caulk without causing some damage to some types of surfaces. For example, if your exterior walls are made of stone, it may be impossible to remove acrylic caulk without damaging the stone. You would then have to apply a larger, wider caulking joint to cover the residue of the old acrylic-based caulk. 



Contact Calfeutrage Apex to remove old caulk

In conclusion, removing old caulk around windows isn’t that difficult! However, don’t underestimate the time needed to do it, especially if you have several windows to do.

If you prefer to leave this job to caulking specialists, you can also ask for help from Calfeutrage Apex. Our team travels all over the South Shore of Montreal to offer professional services at competitive prices. Contact us for a free quote!