I have a brand new window and it seems like it could slide a little smoother if it had some lubricant in the rails. It does open fine but it feels like it could be broken in more.

Is there any lubricant I can use in the rails to make it slide better? enter image description here

  • Were thew windows insulated around the perimeter with foam?
    – Jack
    Nov 18, 2015 at 2:44

2 Answers 2


Usually silicone is good for this kind of thing, doesn't make a mess, screw up wood finish, gum up plastics and rubber, etc. A little goes a long way. Just a tiny squirt on the rails, work it up and down a few times, wipe off any excess.

On older wood on wood windows, wax works very well, in a pinch, or if you don't have any wax, rubbing soap on it.


There are a few things that will keep a double hung tilt sash window from operating smoothly. One is bowed jambs from too much insulation being stuffed into the gap at the rough opening. Using regular foam and not the minimum expanding foam specified for doors and windows will really do a number on the jambs too.

The other is and I have done this myself and others in my crew too. We damaged a few window tracks by removing the sash for the installation of the frame. We popped the jamb liners to screw behind them so the screws would not show, then reinserted the liners and the sash. What happened was, the window sash when it was put back in, did not set into the bottom properly and only one ballast was pulling up on the window to assist the lift. The other side that was not set in place properly moved the plastic track around enough in the slot to the point where, when the window bottom was set in place properly, it did not ever work the same way. The was on only one brand of window, other brands would only act stiff but not trash the track.

  • How about a lubricant treatment to smoothen it ?
    – amphibient
    Nov 18, 2015 at 3:12
  • That may be all it takes, but something is making a new window behave under par. Have you checked the side jambs for bowing?
    – Jack
    Nov 18, 2015 at 6:47

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.