by Lee Wallender
Tools and Measurements

After an unusually high estimate for replacing windows, many a homeowner has considered a do-it-yourself window replacement.

The process of replacing your own windows is pretty much the same as professional window companies do, but with a few less bells and whistles.

Please note: as each type of replacement window is different, it is highly recommended that you pay close attention to the installation instructions included with your window. However, following are general replacement window installation instructions.

Window Replacement Tools and Materials

• A good dripless caulking gun and plenty of caulking tubes
  
• A square
  
• Wood shims
  
• Tape measure
  
• Miter saw
  
• Hammer
  
• Strong cordless drill
  
• Screwdriver
  
• Wood chisel
  
• Utility knife
  
• Small prybar (not the larger wrecking bar)
  
• Replacement window

Measure Your Existing Window

Please note that you are measuring windows from the inside of the house, not the outside.

1. Measure Width
Run tape from one side of the window jamb to the other side of the window jamb. You will be measuring from the inside of one jamb to the inside of the opposite jamb. Because windows can warp and skew over the years, measure at bottom, middle, and top. Hopefully all measurements will be the same or within 1/4". If not, choose the smallest measurement as your "keeper."

2. Measure Height
Same routine here but do it vertically. Again, you're measuring from the inside of the sill (that is, top) to the inside of the top window jamb (that is, its bottom-most face). Measure left, middle, and right, and choose the smallest measurement.

Just a note--you're keeping the smallest measurements so that the replacement window you order will fit in the opening. Any gaps will be filled in later.

Removing Old Windows

You're working from inside the house. The sash is the part of the window that moves. The stops as those thin, vertical pieces of wood that prevent the sashes from falling inward into the house.

Remove Stops

Using your pry bar, screwdriver, utility knife, and ingenuity, remove the stops. This calls for delicacy and you don't want to damage the surrounding materials. This is why I call for using everything from the utility knife (to slice paint that may adhere the stop to the window frame) to the pry bar (once you've got a gap going, you can switch to the pry bar). Shims are great, too, for protecting the surrounding materials when using the pry bar or hammer claw.

Don't destroy the stops. Set them aside for later use.

Remove Sash

Remove the inside sash.

Cut any sash cords or chains (only older windows have these). No need to remove the weights. Let them fall into their pockets. Cut away any exposed rope and let the rest fall down.

Slide the outside sash down. Remove the parting beads. Parting beads are simply those vertical strips that keep the sashes on track. Discard, as you will not need them again.

Remove the outside sash. Do not remove the outside stops.

Clean and prepare inside faces of window jamb and sill to accept the new replacement windows: sand splintered wood, patch small holes with wood putty, and fill large holes with tufts of fiberglass insulation.

Installing the Window

Dry Run and Preparing Window Unit

Before doing any caulking or any non-reversible procedures, set the new window in the existing window opening and get a feel for how it will fit. Position the window sashes within your new window unit at the center of the window unit. Next, slide the bumper stops toward the center also so that you can see the four mounting holes on the sides of the window unit.

Caulking

Caulk along the inside of the outside stops on the jambs.

Mark the sill for the sill angle. Caulk and install the sill angle.

Insert the header piece (sometimes called an expander) on top of the window unit and caulk along the top of it. Secure header/expander with the provided screws.

Install Window

Put window in opening. Use your square to check all four corners for squareness.

Tap in shims where needed to square out the window. Do not knock shims all the way in "flush." Leave about one inch sticking out, because you may need to later remove them.

Screw in the provided mounting screws at the top and bottom of each side jamb. Do not over-tighten the screws.

Move the header up until it closes any gaps between replacement window and window frame, and use the provided screws to fix the header in place.

Test Operation

Test both sashes for smooth sliding. If the sashes are tight, use the adjustment screws to adjust operation. If this still doesn't do it, you may have to knock out shims and try shims that are less thick. If the shims are fine, saw off the protruding ends with a miter saw.

Final Caulking and Stops

Caulk inside of the window. Install inside stops that you saved aside with small finish screws.