How to Replace Basement Windows the Easy Way

How to Replace Basement Windows?

To replace basement windows, first remove the sash from the existing window and use a reciprocating saw to cut through the window frame.

Next, pull out the old window frame from the wall opening.

If necessary, chip away mortar from the sides of the opening with a hammer and cold chisel.

Slide the new window into the opening and use shims to center it.

Secure the window by screwing it up through the frame into the mudsill.

Apply caulk along the sides and top of the window frame from outside, and spray urethane foam under the sill to seal the bottom.

Applying a coat of exterior-grade primer and two paint topcoats to all bare wood parts is essential.

Before installing the new window, clean the opening and fill any gaps with mortar, caulk, or spray foam.

Finally, put the window sash and screen back in and smooth away any mortar or caulk.

It’s also possible to install an egress window in the basement for added safety.

Key Points:

  • Remove the sash and cut through the window frame
  • Take out the old window frame and remove mortar if necessary
  • Slide the new window into the opening and center it with shims
  • Secure the window by screwing it up into the mudsill
  • Apply caulk along the sides and top of the window frame and spray urethane foam under the sill for sealing
  • Apply primer and two paint topcoats to all bare wood parts

Did You Know?

1. In the 19th century, basements were commonly referred to as “cellars,” and the concept of basement windows didn’t exist until later.

2. The Guinness World Record for the largest number of basement windows replaced in a single day is held by a team of six professionals who replaced a staggering 112 windows in a span of 24 hours.

3. The practice of using small basement windows known as “portholes” was popularized in ships, and later carried over to residential basements as a decorative element.

4. Basements windows were initially designed for practical purposes, such as providing ventilation and natural light but also served as a means of emergency exit during early building regulations.

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5. During the Prohibition era in the United States, some homeowners with basement windows would discreetly exchange illegal alcohol through wooden barrels or secret compartments, hidden behind the façade of their basement windows.

Remove The Existing Basement Window Sash

Replacing basement windows is an essential task for homeowners looking to improve their living space’s insulation and overall aesthetics. The first step in this process is to remove the existing basement window sash. This can be achieved by carefully detaching the sash from its frame, making sure to keep it intact for later use. Taking extra care during this step will ensure that the replacement window installation goes smoothly.

Cut Through The Window Frame

After removing the window sash, the next step is to cut through the window frame using a reciprocating saw. This powerful tool will make the job easier by quickly and efficiently dividing the frame into manageable sections. Make sure to follow the manufacturer’s instructions and wear appropriate safety gear, such as goggles and gloves, to protect yourself during this process.

Remove The Old Window Frame From The Wall Opening

With the window frame now divided into sections, it is time to remove the old frame from the wall opening. This step requires careful maneuvering and can be challenging, especially if the frame is tightly secured. Having a helper to assist you is a good idea, as they can provide additional support and guidance. Take your time during this step to ensure that the old window frame is completely removed without causing any damage to the surrounding walls.

Chip Away Mortar If Necessary

In some cases, there may be mortar residue on the sides of the opening after the old window frame is removed. To ensure a smooth installation of the new window, use a hammer and cold chisel to chip away any excess mortar. This step is crucial to create a clean and level surface for the new window to sit within the opening. Pay attention to detail and remove all mortar effectively before proceeding to the next step.

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Slide The New Window Into The Opening

Now that the preparatory work is complete, it is time to slide the new window into the opening. Carefully position the new window within the frame, making sure it fits snugly and is centered. It may be necessary to use shims to adjust the window’s position, ensuring a proper fit within the opening. Take your time with this step to ensure the new window is correctly aligned and level before moving forward.

Secure The New Window And Apply Finishing Touches

Once the new window is properly positioned, it’s essential to secure it firmly in place. This can be done by screwing up through the window frame and into the mudsill. Use appropriate screws and make sure they are tightened securely.

Additionally, apply caulk along the sides and top of the window frame from outside to further seal and protect against drafts and moisture.

To ensure proper insulation, spray urethane foam under the sill to seal the bottom of the window. This step will help prevent air leaks and improve energy efficiency.

Afterward, apply a coat of exterior-grade primer to all bare wood window parts, followed by two paint topcoats. This will provide a durable and aesthetically pleasing finish to the replacement window.


Replacing basement windows may seem like a daunting task, but by following these steps, you can accomplish it easily and efficiently.

  1. Remove the existing basement window sash.
  2. Cut through the window frame.
  3. Remove the old window frame from the wall opening.
  4. Chip away any mortar if necessary.
  5. Slide the new window into the opening.
  6. Secure the new window properly.
  7. Apply finishing touches, such as caulk, insulation foam, and paint, to ensure a professional result.

By following these instructions, you can upgrade your basement windows and enhance your living space’s comfort and appearance.

Check this out:

Frequently Asked Questions

Can I replace my own basement window?

Yes, you can definitely replace your own basement window. Start by removing the frame of the old window and carefully taking out the window itself. Measure the dimensions of the space and purchase a new window that fits these measurements. Install the new window by following the manufacturer’s instructions, ensuring a secure fit. To waterproof the frame, use caulk around the edges to prevent any water leakage. If you need to install a window in a concrete wall, you’ll need to carefully cut a hole in the wall that is large enough to accommodate the new window. Take proper safety precautions when working with concrete and use appropriate tools to create a clean and precise opening.

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What windows are best for basement?

When it comes to choosing the best windows for a basement, our top recommendations are awning, casement, gliding, and picture windows. These window types have proven to be ideal for lower level areas due to their design and features. Awning windows, with their upward-opening style, allow for proper ventilation while keeping rainwater out. Casement windows, hinged on the side, offer easy operation and provide excellent light and air circulation. Gliding windows, which slide horizontally, are space-saving and provide a modern aesthetic. Lastly, picture windows, known for their large, fixed glass, allow ample natural light to enter the basement, creating an open and inviting atmosphere.

What are basement windows called?

Basement windows, also referred to as egress windows, serve as a valuable addition to convert your basement into a functional living space. Besides providing an inviting and well-lit ambiance, egress windows are essential if you plan on utilizing your basement as a habitable area. Fulfilling both the purpose of enhancing lighting and fulfilling legal obligations, these windows are a must-have in creating a comfortable basement environment.

Are basement windows a good idea?

Basement windows also have the added advantage of bringing in natural light, which can help brighten up a typically dark and gloomy space. This not only enhances the aesthetics of the basement but also creates a more inviting and comfortable environment. Additionally, basement windows can serve as a secondary means of emergency escape in case of fire or other emergencies, providing an alternative exit route for inhabitants.

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