Flag Windows

Within the overarching theme of joined windows, you will find numerous different window designs including flag windows. This design consists of three windows with one wide frame fixed in between two slimmer frames. Windows featured in a flag will usually include sliding sash windows carrying all the heritage elements found on traditional timber frames including Georgian bars and run-through sash horns to maintain the association with historic windows.

Types of Flag Windows


Flag windows are available in the sliding sash window style. With our 15+ years’ experience, we’re experts in making windows in PVCu. PVCu is great for heritage applications where bay or other coupled windows may be required; it is easy to maintain and can quite easily be welded and joined. PVC is durable and is a very popular choice for medium and long-term applications because of its long lifespan and resistance to weathering.


Flag windows are also known as triple windows because the unit consist of 3 separate frames coupled together into one. Generally, flag windows or triple windows will feature a middle section that is around twice the width of the frames sitting beside it. The configuration of sliding sash windows can’t be modified, and multiple frames coupled together e.g. flag windows or double windows is often required for wide openings.

Other Joined Window Styles

Iconic VS with bars

Side by Side Windows

Windows are joined using something called a coupler. These are available in different sizes depending on your requirements. The coupler we use to join the sash windows together is one that has been designed for frame to frame coupling with reduced sightlines. With Quickslide’s slim coupler you can couple windows that feature the slimmest horizontal frame sections possible giving you a window solution that isn’t completely obstructed by frame sections. Generally, any double or triple windows will be joined in our factory and no additional assembly will be required.

Doors with Side Windows

To cope with apertures that are oversize, it is common practice to use side or top panels to make up the difference in height or width. Same height fixed glass panels are also known as side lights. For added natural light, you can even couple a window on either side of your door as illustrated. Doors coupled with windows can be scaled to fit your aperture. Complete the look with your choice of double glazing in any of our obscure glass designs. Start designing your new flag windows with our team today. Get in touch using our online contact form or give us a call on 03332 412 240. We look forward to hearing from you.

coupled in french door

Frequently Asked Questions

We offer competitive pricing for our flag windows to homeowners and installers across the UK. Each of our products is priced based on their dimensions and designs, so it would be impossible to give one price. You can use our online pricing engine to request a quote, or get in touch on our online contact form or give us a ring on 03332 412 240.

Flag window installation require a lot of concentration and experience. We have a fantastic installation guide that you can take a look at if you have any questions, or we can provide you with a list of your local installers.

Flag windows consist of either a central wide glass unit or a door, with two narrower windows on either side. This adds a traditional and heritage aesthetic to properties and floods homes with natural daylight. We use advanced manufacturing techniques including joiners to make our flag windows so that they can provide long-term performance.

Yes! Our flag windows are fitted with double glazing that will enhance the thermal performance of homes and achieve high energy ratings. The improved insulation will give people a space that they can feel warm in throughout the year.



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