DIY Window Installation – Step by Step Guide

| Updated on February 13, 2024

Are you considering getting your home windows replaced? After taking into account the cost of hiring a contractor for windows replacement Edmonton, you might have decided to do it yourself.

DIY window installation is not a job for everyone. If you are up for this project, follow these steps to the T to get the job done:

Step 1: Remove the old Window Trim and Casing

You will need a prybar for removing the window trim as well as the jamb extension from around the window. 

Step 2: Remove the Window

Unscrew the old window from its jamb and then remove it. Be careful because the glass of the window can be delicate. 

Some windows have several window sashes with moving tracks. You will have to remove one sash at a time, which makes it easier to remove the entire window.

Step 3: Prep the New Window 

Now that the old window is out of the wall, before you get started with fitting the new window, inspect the wall and the condition of the window jamb. 

Make sure there are no structural damages. Old windows mostly leak which makes the jamb rot. If there is damage, make sure you repair the area or replace the jamb if necessary. 

You must measure the rough opening to make sure it accommodates the new window you are looking forward to installing. Ideally, the rough opening must be ¼ inches to 3/8 inches larger than the dimensions of your new window.

Step 4: Check the Window Stop

You are not ready to install the new window yet. First check the window stop. It’s a piece of wood that is placed around the exterior of the window jamb. The purpose of this piece is to prevent the window from sliding out of its opening. As the name implies, it stops the window from moving. There are good chances that the original stop has worn out and you need to either repair or replace it.

Step 5: Dry Fit Window 

It’s highly recommended to dry-fit the window to identify fitting issues in advance. In case you encounter a fitting issue, address them before installing the window. 

Once these issues are addressed, the window should snugly fit into the opening. Never move forward with the installation until you are satisfied with the fitting of the window.

Step 6: Time for the Installation 

Now that you have done all the preliminary work, it’s time to install the window, which is a pretty straightforward process. Follow these steps to complete the installation: 

  1. Start by running a bead of silicone on the edge of the window stop.
  2. Slide the window into its place.
  3. Put a level across the windows’ top and press shims between the bottom of the window frame and the jamb until the window sits in perfectly.
  4. Adjust the screws that go through the side of the unit for anchoring it to the jamb
  5. Two screws are supposed to go into each side of the window (one in the top and the other one near the bottom).

Step 7: Add the Insulation 

Sometimes, there are gaps around the original window frame. You may insulate those areas by adding insulation. If the gaps are large, cut pieces of rolled insulation and insert them in the gaps. You can use insulation foam spray for reaching the harder spots. 

Step 8: Finish With Paint 

The final step of the installation is finishing the window by painting. After all, it’s equally important to make your window look finished. Windows can be made of different materials like wood or some sort of plastic, but painting them has a similar process. Just like wood, painting plastic is easy if you have the right tools for the job

Important Tips

Window replacement or reinstallation is both complicated and tedious even if the process goes perfectly according to the plan. You must understand that there are two types of window replacements. One is the pocket replacement and the other one is the full-frame replacement. Most of the replacements or installations are pocket type installations.

Keep in mind replacing a wood window is entirely different from installing a standpoint or replacing a metal window. All processes require different tools and skillset.

Since you will be installing the window yourself, you won’t have a warranty. Any damage done to the window during the installation could void the manufacturer’s warranty. Therefore, make sure you know what you are doing.


Follow a strict procedure during and after removing the old windows. It’s important to waste the old fixtures properly. Contact your nearest waste management company for recycling or disposal of the old windows by looking it up on the Internet.

Good look with this DIY project of installing your home windows.

Bhavya Singh

Social Media & Lifestyle Expert

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