The sill is the masonry below the window or at the bottom of your door. It serves as a sill for the windows and allows the rain to drain away from the building. Its role is essential to ensure the water-tightness of your home and avoid problems related to water infiltration.

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Door sill: Work performed by Calfeutrage Apex South Shore Caulking.

Sill joints that are deteriorating  Apex caulking Window sill

Longer sills have at least one mortar joint, which degrades over time due to temperature changes and the natural elements. While degradation of sill mortar joints is normal, it is not desirable. 

When water gets into the cracks in the mortar that binds your window or door sill, it attacks the cement or stone of your sill and finds its way behind the bricks. With the change of seasons, our cold winters, and the extreme temperatures we experience in Quebec, bricks can easily burst, resulting in costly repairs.

Maintaining your home’s window sills

Repairing and maintaining your window sills is a money-saving option.

The first step is always to take the time to observe your sills. You want to check for cracks or signs of deterioration. 

Step One – Removing the deterioted mortar joint and preparing the surface.

To replace the joints of the door or window sills, we begin by carefully and gently removing the entire cracked or deteriorated mortar situated between them. This process is essential to maintain the integrity of the sills. Although the complete removal of the concrete is time-consuming and labor intensive, it’s necessary to ensure proper adherence of the new sealant that will be applied between the sills.

We continue by thoroughly cleaning the joint surfaces, removing any debris, dust, or dirt.

Next, we insert a Backer Rod  into the significant gap between the sills to support the new sealant. The correct size of the Backer Rod is determined by the depth and width of the sill joint. This comprehensive procedure ensures effective sealing and stability.

Click here to watch how Calfeutrage apex removes the mortar between the sills.

Step Two – Caulking the sill.

Next, it’s time to apply a quality caulking product to seal the sill joint. We use Dowsil Contractors Concret Sealnat, a superior caulking product with an outstanding adhesion to masonary, durability , flexaibilty and and recovery from extension and compression.

Last step – finishing

Finally, we smooth, shape and tighten the joints for a perfect air-tightness and flawless appearance.                                                  

Caulking the sill of a window by Calfeutrage Apex Caulking.

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Prevention rather than cure.

Caulking the joints of your sills is an operation that prevents excessive wear and tear on the mortar. It is a maintenance step for your home that should be performed as soon as weaknesses appear. If you neglect the maintenance of your sills, the cracks could become bigger, attack the structure of the building and require masonry work to redo new sills, replace bricks that have burst, or replace various materials following water infiltration or the appearance of mold.

Modifying concrete window sills with aluminum.

If the architectural style of your building allows it, it may be advisable to cover concrete sills with aluminum after having perfectly sealed the cracks. This is an economical option in the long term since the mortar binding the different parts of the sill will no longer need to be sealed. However, it is important to make sure that the sill is perfectly caulked since it will no longer be possible to check its condition once it has been encapsulated by aluminum. 

Healthy window and door sills.

They may seem to have only a decorative role, but the sills of your home’s windows and doors are important for keeping your house airtight. The angle at which they are installed allows for optimal drainage of rainwater and supports the opening of your windows. Don’t let the wear and tear of time and the changes in our climate crack the mortar of your sills and compromise their effectiveness. Take the time to maintain them or contact a specialist.

allège de fenêtre calfeutrage Apex rive sud

                                                                                     Window sill caulked by Calfeutrage Apex Caulking


Calfeutrage Apex Caulking is a professional caulking company that specializes in the caulking of commercial, residential, industrial and condo buildings:

Window caulking

Door caulking

Expansion joint caulking

Caulking as a pest control solution

Thermo Joints.                                                                                                                                             

Caulking for window and door sills.

For a free estimate, call: 438-871-4504 , or Fill out this form: http://calfeutrageapex.com/contact-us/

Apex caulking, window caulking south shore of Montreal    Apres Calfeutrage Apex Caulking