Blocked sash window | Sash window stuck

Why does this happen and ways to fix it

Blocked sash window | Sash window stuck

When a sash window gets stuck suddenly, it can be very worrying for the homeowner. Not only is your home’s security compromised, but you may not know how to fix the window and the issues causing it to be blocked.

Thankfully, though, there are only a few reasons why a sash window becomes stuck. Some of the issues with this type of window are easy to secure, while others are more involved and may require a professional sash window repair company.

So, let’s look at why sash windows become blocked to help you diagnose the issue causing your stuck window quickly.

Why does this happen?

Blocked sash window

A sash window can become stuck for a few reasons. The most common reasons, though, include:

A sash cord has snapped

If a sash cord has broken, your window will have twisted within the frame and may have lodged in place firmly. If a snapped sash cord is the cause, you will notice some twisting of the window.

A weight has detached

If a weight has detached from the window, this can cause the sash cord to jam inside the frame. This does make the window feel heavier when opening, which is a tell-tale sign of this issue.

Blocked sash window

The cord has come off the sash

If the cord has come off of the window, this is likely due to poor installation in the first place. It can also be due to excessive force when opening the window. However, this can cause the nails that hold the cord in place to move and wedge the window open.

The mortice and tenon joint has separated

If any of the joints in the sash have opened up, this will make the window too big for the frame. This is usually due to excessive force but can also be a sign of poor craftsmanship or lack of glue in the joint. There are no quick fixes for a failed joint in the window, and a professional must be called to repair it.

A foreign object has fallen into the window mechanism

If a random object falls into the window frame, this can lead to a jam. We will get to how to fix jams like these in just a moment.

Your sash windows have been painted recently

If your sash windows have been painted recently, this extra layer of paint could be causing the window to bind. If you have pulled the window forcibly to open it, this extra paint could wedge the window open.

How to secure your sash window

Many of the issues above do require a professional window specialist to come and fix them.

Sadly, unless you are a DIY expert, fixing sash windows is not that easy. So, the information below is intended to help you keep your home secure and not have to pay emergency prices for your sash window repair. You can use the advice below to secure your window and then seek help at a more reasonable price.

A snapped sash cord

While it isn’t easy to repair the sash cord that has snapped, you can at least secure the window in the frame for the time being. To do this, you will need to access the outside of the window to look at the sash cord groove. If you need a ladder to do this, please be safe. If you are unconfident on a ladder, please call a professional to help.

Once you have access to the sash cord groove, you can cut the sash cord as close to the sash as possible. Since it has snapped, it’s no longer needed and cutting it as close as possible will prevent any jams in the next few steps.

Next up, you need to close the window. To do this, simply nudge the corner of the window that is jamming; this should realign the window enough for you to close it. You will need a friend to help with this step.

Since one side of the window no longer has a sash cord, it will be much heavier to move. Once your window is closed, you can then use screws (larger than 40mm if you have them) to secure it. Put a screw on each side of the window frame to hold the sash up.

To re-cord the window, you will need a professional window repair company unless you are highly skilled at DIY. Re-cording involves removing the window, and the window frame and things can easily go wrong if you are not trained.

Sash cord jammed or wedged within the window frame

The first step in correcting this issue with sash windows is to remain calm. The less you play with the window, the more likely it is that you can free up the cord. Look for the cord. If you can see the cord, there is a very good chance of freeing the window without needing to call a professional.

Grab the sash cord (pliers will help with this) and try and fit it to where it normally sits (wedging the sash in the opposite direction as much as possible can help you do this). Pull the cord upwards and free of the sash and place it into the normal position.

After this, you can repeat the processes we mentioned above for a snapped sash cord. Unfortunately, with a jammed sash cord, it will need to be replaced before you can use the window again.

cord has come off the sash

Sash window is stuck open due to the cord falling off, and it is jammed on the nails

There isn’t really an easy fix to a sash cord falling off. It is actually even difficult to make the window secure if the nails have really embedded into the sash. The best chance at securing the sash is to remove it so that you can remove the problem. If you don’t know how to remove the sash, you can research it, but do be careful!

Your only real hope here is to remove the parting bead from the sash. This will allow you to remove the cord and nails. You can then cut the cord, secure the window and wait for a professional to re-cord the window.

Sash windows stuck after recently painting

If your sash windows have become extremely tight to open after repainting or nearly impossible to open, you don’t have too many options. You can either strip back all of the paint inside the stiles of the window and lose the time it took to do it in the first place.

Or you have one other easy option. You can try and lubricate the wooden sash frame and the stiles. Some people use WD40, but we prefer recommending a silicone lubricant, as this won’t stain your windows a yellow colour like WD40.

Spray the lubricant into the stiles and try and open your window as far as you can. You will need to do this a few times to coat the frame and the stiles with the lubricant. If this works, you’ll need to top up the lubricant every so often to keep it working. If it doesn’t, you will need to strip the paint


Now that you know how to secure your sash windows when an issue occurs, we thought we’d answer some FAQs about sash windows along the same lines. These questions may help you if you can’t identify the cause of why your sash window is blocked or stuck.

How do you unjam a sash window?

If your sash window has jammed, there is usually a very good reason for it. Most sash windows become jammed because of being painted by a previous owner and simply being left for someone else to worry about. If this is the case, there is a section just below about how to free a jammed window when it has been painted shut.

Another cause of a sash window being jammed could be the sash cord snapping or jamming. If this happened while the home was in the hands of the previous owners, they might have never got around to repairing the window but instead secured the window. So, if your window hasn’t been painted shut, it is likely that the sash cord has snapped or jammed at some point. You can tell if the sash cord has snapped if the sash twists as you try and open it. This will require some DIY to replace the sash cord yourself or call in an expert to help you.

How do you unlock a sash window from the outside?

To open a sash window from the outside, you can either use your hands or a crowbar. Some people have mastered opening sash windows by simply pressing on the beading in the middle of the bottom window and carefully using upward pressure. Once you have a bigger enough gap for your hands between the sill and the window, you can open the window as normal.

The crowbar method is a bit simpler but can be more destructive if you aren’t careful. You can wedge the crowbar under the window (the corner of the window is best) and tap the crowbar with a hammer. If you lay a block of wood under the crowbar, this limits the damage done to the window but doesn’t eliminate it altogether. Once you have the crowbar underneath the window, you can use your leverage to lift the window and open the window fully with your hands.

If your sash window is locked, this is a different story. If your sash window has any kind of lock in place that is preventing it from opening, you need to remove the lock if possible, lubricant the lock, or get a locksmith in to free it up.

How do you unblock painted shut sash window?

If your sash windows are painted shut, there are a few things you can do. When we say ‘painted shut’, we mean that fresh paint has sealed the bottom and top of the windows closed, rather than blocked the stiles like in the example above.

To free your windows from fresh paint, you will need a putty knife and a utility knife (Stanley knife). First, take the utility knife and carefully cut the paint along the bottom of the window (where the window meets the window sill).

Then, use the putty knife to carefully create a separation between the sill and the sash (or the top of the window frame and the sash, depending on where the issue is). For thicker areas of paint, a chisel and hammer can be used. A solid hit with the chisel should remove excess paint easily.

Just take things nice and slow. If you rush this, you may chip the paint or cause damage to the window. You may need to chisel and scrap the window frame if the frame has been painted to the stiles too. Once you have the window open, it is worth adding some lubricant to the runners, as chances are, there is probably another layer of paint in there too. You can also use a paint scraper to remove any access paint from the inside of the runners, which will greatly help your window run freely again.

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