How To Replace A Window

There are many reasons to replace a window in your home, and there are several more reasons you might want to avoid the job. No matter what the guy at the home improvement store tells you, replacing a window is a big job, and there is a possibility that you could screw it up. This is one of those jobs that if you do screw it up, there is a possibility of expensive reminders down the road.

Steps You Need Take Replace Window © Copyright Matt Thompson and licensed for reuse under this Creative Commons License

At the same time, replacing a window is not rocket surgery. If you take your time, go about it thoughtfully and deliberately, you will probably be fine. Best of all, replacing a window is one of those jobs that not only has beautiful results, but it is one that gives great satisfaction to know you accomplished it.

The job has a pretty basic tool list. If you don’t have and know how to use these tools, you may want to think about calling in a professional glazier. This is not a sophisticated list however.



Measuring Tape

Spirit Level


Pry Bar

Caulking Gun

Step 1: Determine you need to replace the window, and get a new one.

If your old window is not operating properly, take a good look at the hardware. It may be cheaper and easier to replace a few screws than a whole window. If the windows you have currently installed are inefficient single pane windows, or just plain ugly, go ahead with the replacement. Most contractors will have used standard sized windows, so it should not be hard to find a new one.

Step 2: Carefully Remove the Old Window.

Remove the trim pieces from around the window so you can get to it. Remove all the screws that are holding it in place, and carefully tip it in or out and remove the whole frame. Once it is safely out of the way, remove all of the old caulking and sealant. While you have everything out of the way, inspect the wood in the window frame to insure there is no rot.

Windows are a common place for rot to take hold, which is why it is so important to do the job well. If the wood is in good condition, then proceed with the job. If rot has already begun, it will only get worse, to the point your new window may fall out!

Replace the rotten board, treat the area with a fungicide and take special care to ensure the new window is well sealed.

Step 3: Lift the new window into place and ensure that it is square and level.

This will go better with some help. Lift the window into place, and have your helper support it. Use the level along the bottom of the window to be sure it is level, if not shim accordingly. If you can, place the shims under the screw holes of the new window.

Use your tape measure from corner to corner to be sure the window is square before using the screws to secure it in place. If the screws go through your shims, you will know they are locked in place. It is a good idea to recheck for level and squareness at this point.

Step 4: Finish the job!

Fill any gaps with caulk so that no water can get between the window frame and the house frame. Replace the trim and enjoy your new window!

As you can see, replacing a window is a straight forward job. If you want to avoid the hassle, or if the window you need to replace is in an inconvenient or dangerous place, you can always call the professionals at Associated Glass.