UPVC Mechanical Joints on window corners

Mechanical sash joints: why they matter

a close up of the mechanical joint used in our upvc sash windows

One of the most distinctive features of the Heritage and Ultimate Rose sash windows from the Rose Collection that sets them out from other uPVC sashes is the use of mechanical jointing in their design.

What is a mechanical sash joint?

For hundreds of years timber sash windows were made using the same traditional woodworking and joinery techniques. One of the most distinctive of these techniques was the ‘mechanical sash joint’. This is the type of joint that holds the four corners of the window together. Traditionally, these were ‘Mortise and Tenon’ joints; where the ‘Tenon’ tongue an extruding piece of wood on the end of a timber profile is inserted into the ‘Mortise’ hole and locked in place with screws or glue.

Why does it matter?

It’s important to remember that in the days before high security locks and electric central heating systems, these mechanical joints added extra durability, security and thermal insulation to a property without compromising on aesthetics.

When uPVC began to replace timber as the material of choice for modern sash windows installers and manufacturers found that it was far easier to weld these corners together rather than go through the costly and time consuming process of mechanical jointing. However, this meant that many uPVC sash windows lost the authentic heritage appearance and durability that many homeowners valued them for.

At the Rose Collection, we believe that maintaining historical continuity in our sash design and performance is so important. That’s why the Heritage and Ultimate Rose windows in the Rose Collection, even though made of uPVC, utilise mechanical jointing in their structure.

Benefits of a mechanical sash joint

Although uPVC is a high performing material anyway, the traditional mechanical jointing of a sash window serves to add extra heritage aesthetics, as well as modern levels of thermal performance to a window. This makes it a worthwhile investment to consider. Here are three of the best benefits that mechanically jointed sash windows can provide your home:

Maintained durability

Modern uPVC is strong anyway, and both welded or mechanical joints maintain the overall stability of your window and improve its weather protection, thanks to the internal structure (which is stronger than dated uPVC).

The benefit of mechanical joinery is that it maintains the same strength as welded joints, but enhances authenticity at the same time.

Enhanced traditional aesthetics

Modern uPVC sash windows that use welded joints don’t come close to reaching the authentic aesthetics of mechanically sash jointed windows. If manufactured poorly, welded joints can often look messy, untidy and tacky. In comparison, mechanical joints are hidden from view and provide a much more seamless aesthetic: perfect if you want to keep the heritage charm of your home unblemished.

Market leading sash windows from the Rose Collection

Our uPVC sash windows are the best on the market and can help you to effectively replicate traditional styles, without compromising on energy efficiency, aesthetics, maintenance hassle or value for money.

To find out more about the Heritage, Charisma or Ultimate Rose, feel free to get in touch send us a message or give us a call on 01234 712 657.

Categories: uPVC Sash Windows