Window locksmith - When you might need one
July 29, 2025
Upgrading window locks? Installing new window locks? Do you need extra security on your windows? We'll answer these questions & more....
Window locksmiths in London
Window security and window locks can be just as important as having a good front door lock. This is especially the case in situations where the property has windows on the ground floor. It's just as easy to break into a window if it's not utilizing the correct lock or even if it does have the correct lock however it hasn't been installed correctly.
Different windows require different lock so the first thing we do is look at what your windows are made of. Windows, like doors can be made of different composite materials ranging from UPVC Windows to Aluminium Windows. We will cover the material of the window and then the way in which it opens and options for locks .
Wooden windows - Sash window locks
These often open by lifting the bottom window towards the top window. Wooden sash windows are very common in victorian houses and all over London. they can both be very effective in keeping out intruders, but can also be an extremely weak spot in a properties security. Sash windows should always be secured with bolts that screw into the opposite window. This means that neither the bottom window can be moved up, and the top window cannot be forced down either.
Sadly, most Sash windows in London are not secured with bolts on either side unless they have been visited by a window locksmith . They are usually secured with only a small lock that sits on the top of the bottom window. This will normally slide or screw into a part that installed on the bottom of the top window. These are called "Sash jammers" as well, however they are manufactured from metal and not UPVC. The point of connection is very weak and these are very easily removed from outside the property. These locks are also not insurance compliant and for good reason. As they don't require a key to lock, they can be opened in other ways due to them being right above the gap in the window. We advise upgrading these to bolts on either side of the windows as soon as possible. A Window locksmith in London will normally provide advice on upgrading window locks and which locks will work on which window. If not , just contact us here and we will be happy to help.
UPVC Windows - Sash
Since the introduction of plastic/ UPVC it has been used to update many products that were originally made of wood. This includes Sash windows, however they will most likely cost twice the price of wooden windows. These will protect you from the weather in the best way, and can be offered in double glazing options. Normally when installing UPVC windows its best to check that the correct side bolts are installed as in the above wooden sash windows. Sometimes builders will take the shortcut and only install that little lock between the two windows, even with less of a gap due to them being manufactured from UPVC, they will still be easy to open from the outside of the property with just a flat head screwdriver of the right size. Check out our contact a locksmith pagefor more advice.
UPVC Windows - locks
Normally when a window is manufactured from UPVC (Plastic, often white) It will have three main components. The window itself, locking mechanism that sits inside the window along the frame, and the locking handle. For most UPVC windows it is only possible to open the window from the inside via a key inserted into a handle. These are usually very secure as the only way to open the window is from inside the property - provided the handle is turned with the window fully closed. To ensure full security turn the key to lock the handle as well.
If you are still looking for ways to upgrade security on your UPVC windows you can call a UPVC window locksmith to install "UPVC - Sash Jammers". These hang over the edge of the window/ frame and ensure that if not turned away, from inside the property, will not allow the window to open. It's even possible to get lockable sash jammers , these ensure that not only do you have to be on the inside of the property but also need a key.
Wooden/ Metal windows - Casement
Despite being very common in the UK and London before Sash windows were introduced, these windows can be vulnerable to a number of attacks, as such they need to be secured correctly, we'll go into this once we cover what casement windows even are as they aren't that common anymore. A casement window is a window that is attached to its frame by one or more hinges at the side. They are used singly or in pairs within a common frame, in which case they are hinged on the outside. Casement windows are often held open using a casement stay, they are also locked with this casement stay. The casement stay is normally a length of metal bar at the bottom of the window with multiple holes along the length of it, these holes are used with a pin to hold the window open or closed.
As it's fairly easy to use a slim metal clothes hanger and simply move this stay, we advised installing locking casement stays or bolts that go into the frame and stop the window from opening without a key.
Once secured properly by a window locksmith , these windows do offer more protection from the weather and drafts as the windows close into each other as opposed to sliding against each other.
We hope we have done enough to cover all window types in London, if you happen to see or know of other window types or window locks, why not contact us? Oh and if you can't open a locked window, or can't close an open window (it happens with UPVC Tilt & Turn windows when the UPVC handle fails or the mechanism fails) contact us if you need a Local Window Locksmith .
If you are looking for a lock change locksmith, you have come to the right place When someone searches for lock change locksmith, they’re seeking more than just a service—they want a trusted partner to keep their property safe. At SMS Locksmiths, we understand that replacing or upgrading locks is about security, peace of mind, and protection for your home or business. With years of experience serving London and the surrounding areas, our team of fully trained, DBS-checked locksmiths delivers reliable, professional lock change services every time. In this comprehensive guide, we cover everything you should know about changing locks—from why it matters and when to do it, to choosing the right locks and understanding the advantages of using professionals. By the end, you’ll know why SMS Locksmiths should be your first call for all lock and security upgrade needs. 1. Why Change Your Locks? Changing locks is about more than just replacing hardware. 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Here’s How to Book Call us now for immediate assistance or to schedule a visit Message us via GMB or book through our website Email for a quote if you’d prefer to avoid phone calls Final Thoughts lock change locksmith isn’t just a search phrase—it’s a critical service for secure living and working environments. At SMS Locksmiths, we deliver top-tier products, expert service, and total transparency. Don’t leave your security to chance. Contact SMS Locksmiths today for fast, reliable, and guaranteed lock change services across London.
Getting locked out is never fun — but if you're in Clapham, help is just a call away. Whether it’s late at night or first thing in the morning, SMS Locksmith offers fast, reliable locksmith services throughout Clapham with no call-out charges and 30-minute average response times. Step 1: Don’t Panic We know it’s stressful, especially if it’s cold or you have somewhere to be. Try to stay calm and check for any open windows or alternative entry points (safely, of course). Step 2: Avoid DIY Entry Trying to force the lock or use makeshift tools can damage your door – and cost you more in the long run. Always leave it to a professional. Step 3: Call a Local Clapham Locksmith We’re based nearby and can usually be with you in under 30 minutes. Our experienced technicians use non-destructive methods wherever possible to get you back inside quickly and safely. Step 4: Consider a Security Upgrade If your lockout was due to a lost or stolen key, now might be the perfect time to consider upgrading your locks. We offer a full range of British Standard and high-security locks. Need help right now? Visit our Clapham Locksmith page or call us directly for immediate assistance.
