When it comes to making home improvements, we are anxious to see results and changes quickly. However, some invisible steps are essential for successful renovations. These steps often require time and precision and this is especially true when it comes to window caulking. Generally, the old caulk must be removed before applying new caulk to a residence, condo or commercial building (in some cases, it is impossible to remove the old caulk). These steps, sometimes time-consuming and less gratifying than applying new window caulking, must be completed with care, ideally by caulking experts.


Why is it necessary to replace window caulking?

Homes, commercial buildings and condo properties on the South Shore of Montreal are subject to humid and biting winters, followed by hot summers, high winds during fall and various periods of thawing and freezing in the spring. These circumstances are hard on window caulking, door caulking and caulking of various components of homes in the area and accelerate the ageing process for caulking, which then must be replaced. Good-quality exterior window caulking prevents cold air from entering homes in winter and hot air from finding its way in during summer. Water leaks and insects are also blocked by carefully executed window caulking.

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Why is important to remove the old caulk before applying new caulk to doors and windows?

Old caulk tends to harden and crack over time. Once it cracks, humidity and dirt find their way into the materials covered by the caulk. If the old caulk remains in place, it is impossible to dry the surface, clean it and remove the dust. To protect the home’s construction materials, it is essential to remove caulk before caulking doors and windows and starting over.

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Why do we avoid applying a new sealant over an old sealant?

It is important to understand that a new caulk adheres to the surface it is applied to. If the surface is rough, adherence will be unbalanced and the life-cycle shortened. Most types of window caulking are incompatible with each other and have a tendency to repel each other if one is applied to another. In other words, they will not ensure a strong bond on a wider surface. In addition, no matter the type of window caulking used in the past, the old caulk will shrink over time and the new caulk will come off. If the steps necessary to remove the old window caulking are not followed carefully and performed by professionals, it is possible that new window caulking will be needed much sooner than if the steps for removing caulk are respected.

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Is it always necessary to remove the old caulk?

For window and door caulking, it is always advisable to remove the old caulk, but it is not true to say that old caulk must always be removed in every situation. Some building structure materials could be damaged if we try to remove the old caulk. It is generally impossible to remove the old caulk that was applied to the fascia, soffit, some specific architectural elements and some siding joints. It is important to follow expert advice from Calfeutrage Apex to avoid damaging building elements. However, these situations only represent 5 % of caulking replacements on homes and buildings.

Situations in which removing old caulk is impossible:

  1. When caulking joints are completely retracted it is physically impossible to access or remove them, even with tools. It is impossible to extract old caulk located in corners where the angle is less than 90 degrees (between 1 and 85 degrees). We often observe this situation when bow windows or bay glass meets flat sections of a wall.
  2. When caulking joints are so thin or degraded, it is useless to remove them. Ex.: When a transparent thermoplastic caulking joint is so old that it is disintegrating, trying to remove it is counterproductive and useless because there is almost nothing to remove.
  3. When removing caulking joints could damage the materials of the surface they touch. For example, it is not recommended to remove the old caulk that touches roof flashing, the material behind the siding or material on a soffit. It is also important not to remove the old caulk that is touching a material that is falling apart (such as a worn-out air vent).

Which tools do Calfeutrage Apex experts use to remove old caulk on doors or windows?

Our experts work with a variety of tools that can be adapted to the different situations they may encounter. They have electric knives as well as utility knives with retractable blades. Long-nosed pliers can also be useful for removing residue around windows, as well as a brush, vacuum cleaner, solvent and clean cloth to thoroughly clean the surface. The Calfeutrage Apex team has many years of experience, allowing them to know quickly which tool in their kit will provide the best aesthetic results and work best for each particular situation.

How to remove old caulk?

It is important to follow certain steps for the successful removal of old window caulking:

  1. To remove caulking from windows or a door, you must first have the right tools. Caulking joints often harden over the years and become difficult to remove. Exposure to the elements and UV rays accelerates the ageing of window caulking and makes removing old caulk more difficult.
  2. Once the tools needed to remove the old window caulking are in hand, the removal work can begin. The first step is to remove most of the caulk. One trick our caulking experts use is to start removing the caulk from the windows by the part of the caulk that has remained the most flexible, often the area least exposed to the sun.
  3. When most of the caulk is removed, the professionals at Calfeutrage Apex use a brush to remove dust and caulk particles from the surface being caulked.
  4. The last step performed by our team of caulking experts is to clean all traces of caulk with a solvent in order to properly prepare the surface to receive the new caulk.


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What differences should be noted when removing various types of caulk?

In addition to assessing where the caulk needs to be replaced, the time of year and the customer’s expectations, Calfeutrage Apex experts use different techniques depending on the type of sealant that was previously used and needs to be removed.

Four main types of caulk are found in homes in the South Shore region:

  1. Silicone caulk:

To remove silicone caulk, Calfeutrage Apex professionals use a knife blade placed flat under the old caulk and push the blade under the caulk to separate it from the surface. Different grades of silicone sealants are available on the market and the degree of difficulty in removing it depends greatly on the quality of the sealant. If a hybrid commercial silicone has been used, the process is simpler than when other grades of silicone must be removed.

2. Polyurethane caulk:

Removing old polyurethane caulk is very demanding. With this type of caulk, an electric knife is often the best tool to use. Although this tool helps to remove old polyurethane caulk, it is a much more time-consuming and complicated process than when removing silicone caulk.

3. Thermoplastic caulk:

Thermoplastic caulking products are the easiest to remove. It usually only takes tweezers to loosen the caulk from the surface it was applied to. This is true on warm or cold days. On the other hand, if it is too hot, it may be impossible to remove since thermoplastic tends to melt in hot weather.

4. Acrylic-base caulk:

Removing acrylic-based caulk is definitely the most difficult task. Professionals succeed by using special tools, such as heat guns and electric knives. It is a task that requires a lot of precision, time and expertise. With acrylic-based caulk, the removal process is difficult and can cause damage to any aluminum or plastic surface. Therefore, the applied caulk joints will need to be much wider to cover the damage caused by the residual caulk left on the stone. In the case where acrylic-based caulk touches the stone of a building, it is impossible to remove it all since caulking material will remain on the rough surfaces of the stone and in its pores. The solution is to apply a larger and wider caulking joint than the previous one to cover the residue of the old acrylic-based caulk.

Entrust your window caulking projects to the professionals at Calfeutrage Apex

The experienced team at Calfeutrage Apex – the caulking experts on Montreal’s South Shore – uses the best and most advanced caulking techniques when tasked with caulking homes, commercial buildings and condominiums in the area. We replace caulk on windows, door seals or siding in accordance with the manufacturer’s recommendations, building codes, safety codes and the highest standards. Our teams travel across the South Shore of Montreal to offer professional services at competitive prices. Contact us for a free estimate: info@calfeutrageapex.com // 438-288-0338

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