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How to Renovate Sash Windows

Many single-pane double-hung windows date to the 19th century, and have a reputation for being drafty, loose in the joints, rattling, or just impossible to budge. We've all seen the scary movie when the character is trying to get to sleep, but the howling wind outside is rattling the old window panes. If that's your window, there's no need to live in fear; it can be easily fixed. Plus, by doing a bit of window repair, you are guaranteed to save on your energy bills. If you're not sure if you have sash windows, or what the components are, then have a look at this article.

Common problems in Sash Windows

A common problem we see with sash windows in Greenwich is locals not being able to open and close smoothly their windows. Before you start, try opening the window, observing closely and feeling for any stiffness or resistance. The sash should slide up both sides at the same rate, if it catches on one side, that is the source of your problem. It might be a sign the window sash is dropping out of the control of the counterbalancing weights. 

Timber decay, for instance, a rotten windowsill, often goes unnoticed. Test the wood with a penknife. If the knife goes in, the wood is rotten. You might also notice a musty smell, which suggests damp and possible timber decay. Open up the weight box and examine the condition of the weights. Remove any debris from the box.

Take a look behind any shutter or in the window case, as dampness can occur in the plaster or wood.

Paint can also lead to windows sticking. If this is the case, the paint will need to be stripped and reapplied.

Repairing a Sash Window

There are two methods for repairing a sash window; in the first, the window is removed, stripped and remade. In the second, the window is fixed while in place, requiring less work but a less clean finish.

Removing and Remaking a Window Sash

If you opt for the first method, you will need to:

  1. Remove the window by either unscrewing or prying off the stops. 
  2. Scrap away the putty to free the glass.
  3. Clean the joints, removing any soft or rotten wood with a rotary tool.
  4. Apply epoxy to rebuild the cleaned-out joints, returning them to the original shape.
  5. Use an oil-based primer to seal the wood.
  6. Place the glass back into the sash.
  7. Reseal with putty, leave to dry, then coat with an oil-based primer.
  8. Paint the window, and rehang the sash. 

Fixing a Sash Window While in Place

Alternately, if the window is in good condition, give a sharp blow to the centre rail, with a hand or rubber mallet, to unstick the window and get it loose. Failing that, tap a wood block against the sides, to break the bond between stops and sash. (Be careful not to crack the glass.)

If you find a painted-over joint, cut it with a window zipper or flat-blade tool. A healthy dose of lubrication, e.g. candle wax or talcum powder, helps smooth tight sash surfaces and prevents sticking. Or if there is too much paint, remove the excess. The idea is simple; you just need to ease the opening of the window sash.

TR Sash Windows & Carpentry

TR Sash Windows & Carpentry,
4 Bayfield Road,