How to Replace Windows

Window Replacement

If you’ve checked into getting new windows in your home chances are you’ve thought about doing it yourself after getting quotes higher than you’d expect from window replacement contractors. Odds are that you can save money if you get estimates from more than one contractor, speak to the right window replacement contractor, or do it yourself. If you decide to replace your windows yourself it could reasonably take 6+ hours for each window you replace and that is assuming the window is easily accessible from the exterior of your house. Window replacement is a competitive field so you can probably get a bid lower than your initial one if you shop around for different contractors to replace your windows. Good contractors have years of experience and can generally get the job done in a day depending on the size of the job. They can also include features that you may not have the experience to install yourself. But if you do decide to replace your own windows this is a short guide on how to do just that.

Preparation

The most important step to replacing your own windows is measuring. You need to make sure you get the right size windows to replace your old ones so that the installation can go as smoothly as possible. Measure your windows from inside your home and measure from jamb to jamb up and down. Make sure to measure from the bottom, middle and top when measuring horizontally, and from the right, middle and left when measuring vertically. Hopefully all the measurements will be within 1/4 of an inch of each other. But no matter what be sure to use the smallest measurement vertically and horizontally so that the replacements will fit the window opening you will be making. Don’t worry about the gaps now because you will use caulk and insulation later to make sure that your windows seal up. Once you have your measurements you will be able to get purchase your windows. You will also need some other supplies. These include:

  • Caulking Gun and Caulking Tubes
  • A Square
  • Wood Shims
  • Tape Measure
  • Miter Saw
  • Hammer
  • Strong Cordless Drill
  • Screwdriver
  • Wood Chisel
  • Utility Knife
  • Small Pry-Bar and Putty Knife
  • Your Replacement Window

The Replacement Process

To begin your replacement you need to remove the stops. Stops are the thin vertical pieces of wood that keep the sashes from falling inward into the house. Be cautious when removing these pieces because you can re-use them later and they can break rather easily. Use your knives and prybar in the removal of these pieces. The next step is removing the sash from the window frame. Take out the parting beads to free the upper sash. If your windows were previously fitted with sash-replacement kits there won’t be any beads. You just need to press in on the jamb liners and pull the top of the sash forward. Then twist one side of the sash upward to remove it from the jamb liners. After removing the sash you need to pry off the jamb liners. Depending on the age of your windows you may have some wooden stops remaining that you will have to remove.Next you will be prepping the window frame. You are going to want to scrape off any loose or blistered paint from the frame. Next, patch any small holes or cracks with exterior grade wood putty. Larger gaps can be filled with tufts of fiberglass insulation. Sand the jambs and prime and paint the surfaces of the frame. Don’t remove the interior or exterior casings from your frame.

Now you will remove the old sash weights. To do this unscrew the access panel on each side jamb. Next you will insulate behind your window frame. To prep for your insulation you should drill 3/8 inch diameter holes in your sill and head jamb. Make sure to drill one in each end and one near the center. Make sure there is no fiberglass in the sash weight pockets. Polyurethane foam is more effective than fiberglass at blocking air so it is ideal for insulation. Make sure that you use a foam that is low-pressure and expands minimally. Expanding foam will warp your windows and they will have problems opening. Shoot the foam into the holes you drilled until it starts coming out of the holes. You will also spray the foam into the sash weight pockets in the side jambs. The foam needs about 6 hours to harden and then you will break off the extra making sure it is even. When you are finished replace the access panels for the side jambs.

Next you should set your window in the opening to see how it fits and be sure it fits well and evenly. Remove the window and apply caulk to the inside face of the exterior casing, or to the blind stops on the top and sides of the frame. In addition, apply caulk to the windowsill. Now place the window in the frame, putting the bottom in first, then tip the window up and into place. Be sure to press tightly so the caulk will seal the window. Then you will need to secure your window, fastening it loosely at first. Screw the window into place at the top on both sides. Be sure that it is fastened loosely enough that there is no warping and the window can operate. Now you can put in any shims you need to center the window and keep it level. When the window is sitting correctly in the frame fasten screws through the pre-drilled holes, through the shims, and into the jamb. Now you can fill any holes you may have using the foam you used previously.

Now you re-install the sash stops on the inside of your window and you are ready to finish up on the outside. From the outside you need to measure any gaps between the frame of your window and the casing. If a gap is less than 1/4 an inch can be caulked, but a gap that is wider should be stuffed with foam rubber backer rod to close the gap to under 1/4 of an inch before being caulked. When the exterior is sealed your installation is complete. All that is left is priming and painting or staining should you choose to do so.

The replacement of a window can be completed on your own, but don’t expect it to be a quick procedure, especially if you don’t have construction experience. There is always the possibility of something unexpected occurring and complications are bound to arise. If you have more than one window to deal with you may not have the time or the patience to complete the job. Window replacement contractors have years of experience and can get jobs done in a timely fashion.