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PVC windows being manufactured.

PVCu casement windows continue to be the most popular choice amongst most homeowners given their value, versatility, thermal and weather performance and visual appeal, matching a window style that is traditional in Britain’s homes. But not all casements are created equal!

Often, when we think about what’s needed to manufacture the best quality casement windows we will focus on the choice of profile, the glass specification and hardware. But by paying little or no attention to the most important structural components – the screws – you could be undermining your efforts in procurement, specification and production.

Every PVCu windowmaker has their own preferences for which type of profile is best for their business, their installers and the local market. But, we are fortunate as an industry to have so many superb profile systems available to us, so in reality there is not a ‘bad’ choice out there!

So what makes biggest the difference? In addition to the many different types of locks, handles and other hardware available to suit every budget and need, and numerous glazing options, the way the casement window is assembled is one of the most important factors.

Every fastener is recommended to do a specific job

Depending on the design and configuration of the casement window, some of the fasteners will perform a structural role. For example, screws for reinforcement retention, mechanically joining two profile sections, coupling, bay windows and attaching false mullions – all of which will contribute to the structural strength and robustness of the PVCu casement window.

Many other fasteners, however, will be used to attach hardware to the frame. Here it is important to understand the correct usage according to the profile design and type of reinforcement being used. So important is this fixing into reinforcement issue, that it is worth reading our earlier technical blog on this topic to learn more if you are at all unsure.

If the correct fasteners are not used for such elements like locking systems, keeps, handles and door hinges, the engineered quality of these hardware products will quickly be undermined. So opting for a premium quality locking system, for example, might not get the customer satisfaction you were expecting if parts of the system work loose shortly after installation due to the wrong screws being used.

To help fabricators, Rapierstar produces Recommended Fixings Manuals for many of the leading profile systems, including Eurocell, Profile 22, VEKA and Liniar. These are easy to follow but detailed enough to help you avoid common mistakes. You can download the RFM for your profile here.

Focus on your friction stays

One hardware issue that is unique to opening casements is the attachment of friction stays. Here, the choice of fasteners for attaching the friction stay to the frame must allow for sufficient clearance for smooth opening and closing of the sash. This needs a careful focus on the screw heads!

Shallow pan head screws are typically used for friction stays because they are ideal to clamp the flat surface of the hinge arms to the frame. However, in certain circumstances the pan head may come into contact with the friction stay arms as the sash returns to the closed position. This will result in scraping which will damage the screw head and friction stay, and make it difficult for the end-user to open and close.

To counter this issue, Rapierstar developed a low profile pan head screw specifically for attaching friction stays – the LFG. By reducing the height of the screw head further by just a few millimetres without compromising the screw’s clamping strength, we have been able to make this issue a thing of the past. The LFG won’t be needed for every opening casement window, but where you do experience this issue, it is a solution that works.

Don’t forget about corrosion issues

As with all types of PVCu windows and doors, the fasteners you use for manufacturing casements must be right for the location of the installation. What this means is.. what are the local environmental conditions like, and will they pose a problem for standard coated carbon steel screws?

You may know that any property located near a coastline will be in an atmosphere that is particularly aggressive – lots of moisture combined with the salt in sea water. This has a highly corrosion effective on metals that are prone to easy oxidation, such as the carbon steel that is routinely used for window screws. And when screws do corrode, they can quickly work loose and break, completely undermining the join or attachment they are supposed to provide.

But it is an issue that is not confined to coastal locations – the air busy urban areas and those close to major industrial sites and busy roads could also lead to greater risk of corrosion.

So think about whether your casement windows should be assembled using stainless steel fasteners instead. This type of steel is much more resistant to corrosion, which means the screws will easily match the lifespan of the window or door.

Rapierstar offers two types of stainless steel screws – austenitic and martensitic – either of which could provide the corrosion-beating solution you are looking for.

Access technical support from Rapierstar

Rapierstar is the largest specialist supplier of fasteners to the UK and Ireland’s window and door industry, which means we have a wealth of expertise and experience to assist fabricators to make the right choices.

If you have any questions about which fasteners to use in any aspect of window or door manufacturing, simply send us a message via our Contact Us page or give us a call.


This email address is being protected from spambots. You need JavaScript enabled to view it. Technical & Marketing Manager at Rapierstar 


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