How Do I Remove Box Sash Windows?

It is impossible to deny the classical elegance of traditional sash windows. A mainstay in period buildings, sash windows create an eye-catching feature in any home. 

That said, an old sash window can be an energy-efficiency nightmare. Single-glazing is never going to keep heat in your home, while loose frames can be just as damaging to its overall thermal efficiency. While listed buildings and conservation areas can restrict you to repair work on old windows, if you can update to a new set of double-glazed sash windows, you will be rewarded with ongoing savings.

If you’re looking to replace a set of old timber sash windows with new wooden or aluminium ones, your first step is to remove the old ones.

While we always suggest getting in professionals to fit new windows, when it comes to taking out the old ones, we accept this is probably simple enough to tackle yourself, as long as you have a good grasp of DIY. Just make sure to take your time and be careful doing it. You may not be bothered if you break an old window but you don’t want to damage the opening or create a safety hazard with broken glass.

However, there is a technique to it and following a certain order will make the job easier too. In this guide, we’ll show you step-by-step how to remove a sash window in the easiest, safest way possible, so, you can decide if it’s a job you want to tackle yourself.

How To Remove A Sash Window

Tools you will need:

  • A small trim pry bar or putty knife
  • Rubber mallet
  • Stanley knife

Step-By-Step Guide

  1. First up, you need to remove the pieces of wood that run vertically along the side of the window holding the lower sash in place. If you are looking to completely replace your windows, it is simplest to grab a pry bar, jam it behind the stop and lever it out. If you are looking to repair the window and pop the original back in later, you will obviously need to take more time and care.
  1. Use a small trim pry bar or even a putty knife, and use a hammer to gently push it between the stop and the window frame. Repeat all the way around the edge of the first sash.

Years of repainting and resealing can leave the stop cemented in place. If you struggle to insert the crowbar in the first place, try carefully cutting through the layers with a sharp Stanley night first.

Then remove the stop from along the top of the window too.

  1. Remove the bottom sash
    With the stops out, the lower sash will probably be quite loose, so, you may only need to gently pull it out of position. If it seems more jammed, then grab your putty knife/small prybar and try to work that through the gap in the middle of the window where the top and bottom sashes meet. Over years of repair work or repainting, these can become stiff and stuck but should ultimately be quite simple to remove.

Once you’ve worked the lower sash loose, carefully lift it up over the sill at the bottom of the window. As you move the lower sash out of position, you will reveal the pull cords at the side of the window. These could be screwed, nailed or even simply pinched in place, so make sure they are loose before you lift out the sash completely.

  1. Remove the parting bead
    Before tackling the upper sash, you will need to take out the parting bead that sits around the edge of the window. Again, take the time to cut around this using a sharp knife, then gently ease your small prybar into the gap. If the parting bead is in good condition, each side should come away in a single piece. If it doesn’t, then just ease out all the separate parts.
  1. Remove the top sash
    If your upper sash is the one fixed in position, it is likely to a be bit harder to get out. First, cut the paint on the inside and outside of the sash before you attempt to remove it. If you are on the second floor, that might not be possible but be aware that failing to do so can make it a lot more difficult to get the upper sash loose. Layers of paint and caulk will build up across the joints over time, and this can almost lock the sash in place.

    There is also a pulley in this part of the window that makes the removal a little harder still. Keep rocking it gently to work it loose, and take your time. If necessary you can try popping your knife or pry bar between the parting bead and the sash frame, to help work it out – this will also help separate any old paint too.

When it’s free, gently ease it down past the pulley, then remove the ropes just like you did with the bottom sash.

  1. Remove the weights
    Sash windows work using a pulley system, with the ropes running behind the frames. To avoid damaging the frame, the weights and even the window opening, you should take care to remove the weights correctly.

Find the ‘door’ that lets you access the weights. This is usually a fixed piece of wood at the bottom of the frame. Cut the paint around the wood and ease it out to reveal the weight. Doing the process this way means you can support the weights when you cut the ropes. Start on one side, cut the ropes, pull the weight out of the frame then switch to the other side and do the same.

  1. Remove the frame
    At this point, your sash window is basically removed. If you’re replacing the frame, now is the time to lever it out. If you’re just attempting a renovation project with the windows, then simply check the condition of the frames and refinish them as necessary while the sashes are out.

Are You Allowed To Replace Sash Windows?

Generally speaking, there are no more restrictions around replacing sash windows than there are any other types of old windows. So yes, you can replace them if you wish. The only thing that should stop the removal or replacement of your sash windows is when you live in a listed building or a conservation area.

As a homeowner in a conservation area, you may still be able to remove your sash windows but you will possibly be limited in terms of replacement options. You will almost certainly need to source replacements that are in keeping with the character and period of the property and other homes in the area but you may be able to upgrade to new sash windows with double glazing.

Listed buildings may go so far as to ban removal completely. In this case, you may need to seek the support of a professional to restore your existing windows, and you may even be limited on what glass and materials you can use.

In either case, if you are unsure about the restrictions around your home then the easiest thing to do is to seek advice from your local planning department on how to proceed.