Sash Windows

A sliding sash window also known as a box sash or weighted sash are a must for any Georgian, Regency of Victorian property restoration. A traditional sliding sash window is generally made from timber and consists of two sashes one top and one bottom. The two sashes are housed within a box style timber frame that houses the weights that counterbalance the movement of the window. The are many different styles of sliding sash windows throughout the UK, differences across the many styles include the number of glass panes per sash, the style of the glazing bars, fixed side light and arched sashes.

We are proud to offer a large range of vertical sliding sash windows (many of which are on display in our showroom). Each of our Sliding Sash styles can be provided in a choice of materials to suit your home or development, you can choose between Traditional Timber frames, Aluminium and Timber Composite frames or modern white UPVC . Our UPVC range can be enhanced with a white-ash timber finish or a bespoke wood-grain foiled finish to match the style of the property. Our timber sash windows can be supplied in a range of soft and hardwoods and painted in a range of colours and stains. 

With the wide range of styling options throughout all of our sash window ranges, we can design a window to suit any type of property from a new build right through to Edwardian and Victorian properties. Details such as hardware, locks, glazing bars, sash horns, colours and much more can all be customised to suit your property.

Our Sliding Sash Windows can be provided with a choice of movements from a traditional vertical sash window, to a spring balanced window or a Tilt and spring window which are spring balanced with a clever rotation system enabling easy cleaning of the external side of the windows from the inside of the property.




UPVC Sash window

UPVC sliding sash windows are an extremely popular choice when replacing old genuine timber sash windows as they are maintenance free and are more affordable than their timber alternatives. We supply a large range of PVC sash windows from our budget ecolslide range through to our top of the line Bygone Symphony. In some cases Upvc vertical sliding sash windows can be fitted into the main frame to save full removal of the timber boxes and a quick inspection by our fully qualified and friendly installation team will confirm if this might be an option for you.

  • Various colours available.
  • Foil option to imitate wood.
  • Range of sash horn styles.
  • Spring balanced and weighted options.
  • Energy efficient with standard and thin double glazing.

Aluminium clad timber

Alu-clad sash window

Aluminium clad timber sash windows are a great alternative for those looking to achieve the soft homely look of timber on the inside of their property without the maintenance of an all wood window. Externally the windows are clad with aluminium which give the exterior a hard wearing low maintenance facade. Out alu-clad window from The knight Collection is a spring loaded design allowing for a thinner frame and larger glazing. This design can support triple glazing for enhanced energy efficiency whilst still achieving an authentic looking sash window with a top and bottom sash.

  • External custom colours options.
  • Stained and painted interior colour options.
  • Various external casing to add architectural detail.
  • Range of glazing options including triple glazing.
  • Triple glazing option.


Timber sash window

Timber is considered the ultimate material for the manufacturing of sliding sash windows, certain to satisfy the purist. Although we have some very good sliding sash replicas in UPVC a true sliding sash window can only be manufactured from timber. The advances in technology and means timber windows are no longer a maintenance nightmare and only require painting around once every five years.



  • Dual colour option.
  • Range of bead and sash horn styles.
  • Available in redwood and hardwood.
  • Spring balanced and weighted options.
  • Advanced breathable coating system providing maximum protection.

Case Studies

Sash window installation, Wirral

As part of this extensive restoration, the owners of this Victorian property wanted to reinstate the period appropriate sash windows that would have originally been installed. Thanks to the modern technology now available, our client was able to choose a authentic looking UPVC sash window that offered the traditional aesthetic they sought, but with the benefit of double glazing, low maintenance UPVC frames and enhanced security ensuring that they were both secure and warm for years to come.

Regency Property Restoration

Regency property built in the 19th century sympathetically updated with a number of new upgrades including replacing the old tired sliding sash windows. The original windows were looking tired and creating huge cold spots within the room. We worked closely with the owners of this stunning home to supply and install windows as close in detail to the original whilst improving the look and efficiency of the home. Replacement UPVC units where chosen because of the low maintenance required.

Palladion Mansion, Formby

Prestigious development of the Firwood estate in Formby featuring a brand new 7 bedroom Palladian Mansion designed by Southport architects RAL. This large development features over 200 windows, doors and roof lanterns all of which have been supplied by John Knight Glass. Particular attention to detail has been applied to every element of this development resulting in a outstanding building built to the highest of standards. The Portland stone and glazing are some of the features that stand out and contribute to making this building so special

Showroom display

We provide full Technical advice and design service to help you with you decision making and if you are looking for vertical sliding sash windows there is no better place to visit than our showroom where you can see, touch and most importantly try out the windows to ensure you find the sash window that is perfect for you. Take a look through the images below showing some of the sliding sash windows on display in our showroom.