How To Adjust uPVC Windows

In this article, we’ll look at three very common problems that affect uPVC casement windows.

Casement windows are windows that are hinged to the frame at the top or side of the window.

uPVC casement windows that are hinged at the side (side hung windows) are normally hinged with butt hinges. The locking mechanism is located on the opposite side of the frame to the hinges. When uPVC casement windows are hinged at the top of the frame (top hung windows), they’re normally fitted with friction hinges. They open up and outwards from the frame, and the locking mechanism is located at the bottom of the frame.

Here are the three most common problems with these windows:

1. Incorrect alignment on a side hung window

An incorrectly aligned side hung window will normally stick when you open or close it. This happens when the window sash sags on its hinges over time and contacts the frame on the outer edge.

Sagging isn’t the only cause of problems. In other cases, side hung windows have too wide a gap between the window and the frame.

2. Incorrect locking on a side hung window

If the locking mechanism on a side hung window is out of alignment, it will either lock loosely, be difficult to lock or it won’t catch at all when you try to lock it.

3. Incorrect alignment on a top hung window

A top hung window that isn’t aligned correctly will usually be difficult to open and close. This happens as the window sash sags downwards over time and comes into contact with the frame. 

Top hung windows can also have too wide a gap between the window and the frame. This problem is not caused by sagging. 

uPVC windows can have a draught with any of the problems mentioned above as well as being difficult to operate.

Here’s how to adjust the horizontal alignment of an incorrectly aligned side hung uPVC casement window.

If your side-hung uPVC casement window is not correctly aligned horizontally, the window will usually stick against the frame as you open and close it. This effect is common, and it happens as windows sag over time under their own weight. Normally, the window will contact the frame at the top part of the side or along the bottom.

Other problems can result in the window being too far away from the frame. This will cause poor sealing and draughtiness.

Step 1. Identify the window hinges

Before you start, check you have adjustable window hinges.

On butt hinges, look on both hinges for an adjuster located in the centre of the frame side of the hinge. Normally, you can adjust these with a 4 mm Allen key. You turn the adjuster clockwise to move the hinge into the frame and anti-clockwise to move it out from the frame.

If your window hinges do not have an in-built adjuster, you will need to find an alternative method. Usually, this means making adaptations to the window itself.

Step 2. Identify the problem

Next, identify the exact problem with your window.

Open and close your window and look at the edges as you do so. If the window is sticking against the frame, open and close it several times, inspecting the points at which it comes into contact with it.

If there’s a gap between the window and the frame, inspect the window when it is closed. Look at the edge of the window to see the points where the gap between the window and the frame is too large.

Step 3. Adjust the window hinges

Now, adjust the hinges so the window sits correctly against the frame at all points along its edge.

• Turn the adjuster on the top hinge clockwise to raise the bottom corner and bring the edge of the window inwards at the top.

• Turn the adjuster in the bottom hinge clockwise to bring the top corner downward and bring the edge of the window inwards at its bottom.

Turn the adjusters in the other direction for the opposite movement.

Adjust the hinges until you achieve the correct distance between the sash and the frame along its outer edge.

Here’s how to adjust the contact pressure on a side hung uPVC casement window.

If the locking mechanism on your window is not correctly positioned, you will have problems locking your window. Either it won’t catch at all, it will be difficult to lock or it will lock loosely with a poor seal.

Many uPVC windows are built with adjustable locks for this problem. You can tighten the lock for greater locking contact pressure or loosen it to make it easier to close.  

Step 1. Inspect your window lock for an adjuster

First of all, find out if your window has an adjustable lock.

Open your window and look at the side of the sash on the lock side. Normally, the adjuster will be located about halfway between the lock and the bottom of the sash. Most are operated with a 4 mm Allen key.

Step 2. Adjust the lock contact pressure

If your lock is adjustable, you just need to adjust it to achieve the correct locking position.

• Turn the adjuster clockwise to move the lock backwards and increase the pressure when the lock is engaged. This will improve the seal when the window is closed.

• Turn the adjuster anti-clockwise to move the lock outwards and reduce the pressure when the lock is engaged. This will decrease contact pressure when the window is closed but make it easier to lock the window.

Here’s how to adjust the vertical alignment of a top hung uPVC casement window.

If a top hung casement window is not correctly aligned, it will normally be difficult to open and close. This happens when the bottom edge sticks against the frame on opening and closing. Normally, this happens when the window sags under its own weight over time.

In other cases, the window will actually be too far away from the frame, resulting in a poor seal and draughtiness. This problem is not caused by sagging.

Step 1. Identify the window hinges

First of all, check you have friction hinges you can adjust according to the method we will set out.

Friction hinges are made from several thin pieces of metal. They do not open and close smoothly. Instead, the mechanism features parts that create friction. The amount of friction is set so you can move the hinge manually but so it stays in place after you move it.   

If your window is fitted with friction hinges, look closely at the metal strip attached to the side of the sash. Normally, there are four Phillips head screws securing it to the frame.

Step 2. Identify the problem

Next, make sure you understand exactly what’s wrong with your window.

In most cases, the window will be too low in the frame, making it difficult to open and close the window. If this is the case, open and close your window several times, inspecting the bottom edge to see how much it needs to be raised to fit correctly.

If the gap between the window and the frame is too large, inspect the window when it is closed to see how much it needs to be lowered to fit better.

Step 3. Adjust the window hinges

Finally, adjust the hinges so the window fits more accurately in the frame.

1. Open the window completely, and find where the hinge attaches to the sash with the Phillips head screws.

2. Loosen each screw by one complete turn.

Be careful you only loosen the screws holding the hinge to the sash. Do not loosen screws on other parts of the hinge

3. Loosen the screws holding the hinge to the sash on the other side of the window.

4. Now with the hinges loosened, push the window upwards or downwards until it is correctly positioned.

5. Tighten the screws on the hinges so it is held in the correct position.

Finally, test opening and closing your window to check it fits correctly. You might find you need to make further adjustments.

It’s a good idea to regularly check your uPVC windows and give them any maintenance they need. Properly functioning windows will be easier to use, and they’ll make your home more energy efficient.

Here are some ways you can test your windows:

• Open and close them to check for problems.

• Inspect the gap between the window and the frame.

• Test the feel of the locking mechanism as you lock and unlock the window.

• Feel for draughts around your window on a windy day.

You can carry out your own uPVC window adjustments as you need to. Follow the steps in this guide if you find any of the problems we’ve covered.

Make sure you regularly clean your windows. As well as cleaning the glass, make sure the locks, hinges and other hardware stays clean and in good condition.

Problems with uPVC window handles

You might find you have problems with your uPVC window handles  coming loose, jamming or being difficult to turn.

If you find you have any of these problems, you might be able to fix them by just tightening or loosening the screws that hold the handle mount in place. In other cases, it will be more difficult to fix the problem or you will need to buy a new window handle.