How to Loosen a Paint-Sealed Window

Window With White Frame

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Project Overview
  • Working Time: 10 - 15 mins
  • Total Time: 15 mins
  • Skill Level: Beginner

Wood windows are a gorgeous asset to any classic-style home. With their long-lasting beauty, these windows are worth maintaining and holding onto for as long as you can.

But it seems like every old house has at least one wood window that will not open. You try to lift the bottom sash and it just will not budge. The good news is that you can unstick a painted window with simple tools, several of which you may already have on hand.

Why Windows Get Stuck

Wood windows are sealed and unable to open usually because of one of two reasons: either the wood is painted over or the wood is swollen. Sometimes, both conditions are present.

If the issue is paint, a previous homeowner has painted over the windows and frames. The paint bridges from the sash to the window frame. It is usually easy to break through one or two layers of paint just by opening the window. But with multiple layers of paint, the window becomes very difficult or impossible to slide.

Wood swells and expands with humidity. As windows lose their paint or other coatings, there is more surface area than can allow moisture to enter the wood. This is especially true along the outer edges of the sash, where the sash rubs against the inside of the window frame.

Safety Considerations

If you have old windows, it is highly likely that they have been painted with lead-based paint. Even if the top layers are safe acrylic-latex paint, lower layers might include paint that has lead content. Work safely with lead-based paint by wearing personal protective coverings.

Before You Begin

If the window latch is encrusted with paint, unscrew and remove the latch rather than trying to scrape off the paint.

What You'll Need

Equipment / Tools

  • Screwdriver
  • Window zipper
  • Multi-tool
  • Paint supplies (if necessary)

Materials

  • Bar of soap
  • Primer and paint (if necessary)
  • Disposable protective coverings, including a face mask and safety suit (when working on windows with lead-based paint)

Instructions

  1. Try a Window Zipper

    A good solution for painted-over windows is to cut the paint bridge with an inexpensive manual tool called a window zipper.

    Lightly rip the length of the crack, using only the sharp point. Do this several times with increasing intensity until the point has entered the crack.

    Rip with the serrated edge—lightly but with increasing pressure. When the blade can fit all the way into the crack (at least 1/2-inch), that side of the window is free. Repeat for the other three sides of the window.

    What Is a Window Zipper?

    With its thin blade, a window zipper fits right between the window and frame. With its sharp sawtooth edge, it rips through multiple layers of old paint. In addition to the serrated edge, the window zipper has two sharp points at the end. Use one of these sharp points to force the window zipper into the crack.

  2. Try a Multi-Tool

    Cutting into swollen wood with a window zipper is difficult. Instead, use an electric multi-tool. You can use a wood blade if the window is very tight and will not release. But it's usually best to start with the non-serrated scraping blade to limit damage to the window.

  3. Lubricate the Window

    Once the window opens freely, rubbing a thin layer of regular bar soap inside the channel that the window slides in will add lubrication and help it move more freely.

  4. Repaint the Window, If Necessary

    Even if you were careful, inevitably some paint will peel off from the window trim or the window sill. For the best look, paint the entire window trim rather than spot-painting it.

Other Options for Opening a Paint-Sealed Window

If you need to open up a window quickly and you don't have a multi-tool or a window zipper handy, try out these options.

  • A utility knife is a good tool for scoring through the top of the sash. Limit your use of the utility knife for only problem areas, as it is sharp enough to slice into the wood.
  • A putty knife is an ideal alternative for cutting open paint-sealed windows because it is thin enough to fit into the gap. Sharpen the putty knife on a whetstone, metal file, or with an angle grinder to cut through the paint easier.
  • A serrated butter knife can cut through a paint-sealed window. Afterward, do not use the knife for eating, especially if the windows are painted with lead-based paint.
  • A manual wood saw such as a miter saw can cut through some sections of paint bridges. Fine-toothed saws work best.