There’s no reason why you can’t tackle a window replacement on your own, but an important prerequisite for this is to have sufficient skills and the right tools. Replacing a window is a big project and shouldn’t be undertaken without serious preparation. Here is a step-by-step guide to help you achieve your goal so you can professionally install your own windows. 


  • Crowbar
  • Level
  • Screw gun
  • Hammer


  • Window
  • Galvanized screws
  • Felt paper
  • Foam insulation
  • Window wrap
  • Shims
  • Nails


Removing the Old Window

There are a few things to consider during this step: 

  • If you only want a new windowpane, you can contact a glazing contractor for a replacement of just the pane. 
  • If you want to replace the whole window, then you might want to use a stock replacement window. Doing this will save you from shelling out more money for a custom window, but you may need to make a few adjustments to the frame.

Once you’ve decided on what you need, remove the whole window casing using a crowbar. This should include the whole plate and the trim.

Adjusting the Window Frame 

Ensure that the studs and headers are square and plum after removing the window casing. The frame should also match the new window’s dimensions. This step may need you to add new boards to the existing frame and remove some of the exterior siding. Make sure that there’s a ¼ inch gap to allow insulation and adjustments on all sides. 

Installing the New Window

If you removed a part of the exterior siding, remember to place some felt wrap to help keep moisture away. Next, apply window wrap to the window’s exterior frame. Then start installing the window wrap from the bottom of your window and make your way to the top. 

Be sure to install your window from the exterior—push it up until you drive it to the frame. Anchor your window to a strong piece of wood and start screwing the window into place. 

Make adjustments until your window is square and plumb by adding shims and moving the screws to where they’re best positioned. When you’re happy with the adjustments, use nails or screws to secure it from the exterior. 

Wrapping Your Window

Now that your window is square, plumb, and securely in place, it’s time to add a new layer of window wrap. Start by wrapping around the window’s fins; ensure that you overlap your work, covering the surface completely. 

It’s essential that you don’t let the wrap fold back or crinkle up. This is a vital step to keep moisture out, so you need to keep it flush and straight to the window frame.  

Insulating Your Window

To insulate the window, start by placing expanding foam sealant throughout the gaps between the window and the casing. However, be careful not to put too much foam since this may keep your window from working properly. Ensure that the window’s edges are covered with painter’s tape—this will protect its surface. When the foam dries, be sure to gently scrape it off using a knife. 

Replacing the Trim and Casing

After getting rid of the foam, install your new interior casing and replace the existing exterior trim as you like. 

While we’ve provided step-by-step guidelines for DIY window replacement, it doesn’t always work out. Sometimes we aren’t as good at hands-on work as we thought we might be, and the time comes when we eventually throw in the towel. Luckily, US Window & Door offers professional and affordable window replacement services in San Diego. For a free estimate and expert advice on all your window replacement needs, call US Window & Door at (855) 971-0722.


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