Replace Weatherstripping on Slider Windows

Replacing the weatherstripping on horizontal slider windows stops drafts, reduces dust, and lowers energy bills by sealing the gap between the sliding sash and the frame. This guide covers the entire process, from removing the old material to installing new pile or fin-type weatherstripping, and works for most vinyl, aluminum, or wood slider windows. Before you start, measure the length of the channels and the gap width, and buy the correct replacement type (usually felt, foam, or vinyl pile).

What You’ll Need

• Replacement weatherstripping (pile/fin type or adhesive-backed foam, cut to length)
• Utility knife or scissors
• Flathead screwdriver or putty knife (for prying out old strips)
• Cleaning cloth and mild detergent or rubbing alcohol
• Tape measure
• Optional: silicone spray or lubricant for the track

Step-by-Step

1. Remove the sliding sash (if needed). For most horizontal sliders, the sash can be lifted out after tilting it inward. Look for a small clip or screw at the top of the sash; release it, then tilt the top toward you and lift the sash out of the bottom track. If your window has a fixed pane, you can often work without removing the sash, but removing makes the job easier.
2. Clean the old weatherstripping area. Use a cloth with mild detergent or rubbing alcohol to remove dirt, old adhesive, and debris from the channels where the weatherstripping sits. Let it dry completely.
3. Remove the old weatherstripping. If it’s a fin or pile strip, use a flathead screwdriver to pry it out of the groove. If it’s adhesive-backed foam, peel it off; use a putty knife to scrape off any leftover adhesive. Be careful not to scratch the frame.
4. Measure the channel length. Use a tape measure to get the exact length of each channel where the weatherstripping will go. Write down the measurements; you’ll cut the new strip slightly shorter (about 1/16 inch) to allow for expansion.
5. Cut the new weatherstripping. If using a pile or fin strip, cut it to the measured length with scissors or a utility knife. For adhesive-backed foam, cut it slightly longer and trim after installation.
6. Install the new weatherstripping. For fin/pile strips, slide the new strip into the groove, starting at one end and pressing it in firmly along the entire length. For adhesive-backed foam, peel off the backing and press the strip into place, starting at one end and working your way across, smoothing as you go.
7. Reinstall the sash. If you removed the sash, tilt it back into the top track first, then lower it into the bottom track. Make sure the wheels or glides sit properly in the track. Test the window by sliding it back and forth; it should move smoothly but with a slight resistance from the weatherstripping.
8. Check the seal. Close the window and feel for drafts around the edges. If you feel air, adjust the weatherstripping or add a second layer in that spot.

Common Mistakes

• Buying the wrong type. Not all weatherstripping is the same. Pile (fuzzy) strips are for sliding channels, while adhesive foam is better for stationary gaps. Check your old strip type before purchasing.
• Not cleaning the surface first. Adhesive won’t stick to dirty or oily frames, so the new strip may peel off quickly.
• Cutting too long. Weatherstripping that’s too long can bunch up and prevent the window from closing fully. Always cut slightly short.
• Forgetting the top and bottom tracks. Many sliders have weatherstripping on the top and bottom of the sash, not just the sides. Check all four sides.
• Using too much force. Pushing the sash back in without aligning the glides can damage the track or the new weatherstripping.

Tips

• Take a photo of the old weatherstripping before removing it to remember the exact placement.
• For a better seal, apply a thin layer of silicone lubricant to the track after installation—this reduces friction without harming the weatherstripping.
• If you have a double slider (both sashes move), replace weatherstripping on both sashes at the same time for consistent performance.
• Consider using a weatherstripping kit that includes both pile and fin strips if your window uses both.
• In cold climates, choose a thicker pile or foam for better insulation, but ensure it doesn’t impede sliding.

Troubleshooting

• Window won’t close fully. The weatherstripping is too thick or too long. Remove it and trim 1/8 inch off the length, or switch to a thinner profile.
• Draft still coming through. Check all edges; you may have missed a spot. Use a candle or incense stick to locate the leak, then add a small piece of weatherstripping there.
• Sticky adhesive residue. Use a citrus-based cleaner or rubbing alcohol to dissolve old adhesive before installing new strip.
• Sash won’t slide smoothly. The weatherstripping may be catching on the track. Apply silicone spray to the track and the weatherstripping, or trim the strip slightly.
• New strip keeps falling out of the groove. The groove may be too wide. Use a thicker pile strip or add a thin bead of silicone adhesive to hold it in place.

Frequently Asked Questions

How often should I replace window weatherstripping?

Typically every 5-10 years, depending on climate and sun exposure. Check annually for cracks, gaps, or loss of flexibility.

Can I use foam tape instead of pile weatherstripping?

Yes, foam tape works for stationary gaps, but it may not slide well in channels. Use pile for sliding parts and foam for fixed edges.

Do I need to remove the window sash to replace weatherstripping?

Not always, but removing it makes the job easier and ensures a cleaner installation, especially for the top and bottom tracks.

What’s the best weatherstripping for a slider window?

Pile (or fin) weatherstripping is generally best for sliding channels because it’s durable and allows smooth movement. For the interlocking meeting stiles, a fin-type is recommended.

Can I paint over weatherstripping?

It’s not recommended—paint can make it stiff and reduce its sealing ability. If you must paint, do it before installation.

How do I measure the gap for weatherstripping?

Close the window and measure the gap between the sash and the frame with a feeler gauge or a thin ruler. The weatherstripping should be slightly thicker than the gap to compress when closed.

Related

• How to Print Text Messages from Android
• Fix Windows Defender Threat Service Has Stopped
• iPhone Hot? How to Stop Phone Overheating