R9 unglazed delivers installation efficiencies to the installer but also far more flexibility to the end-user should things go wrong.

“You never want to sell on a negative but IGUs can and do fail. If they’re glass bonded, it’s a real headache to replace them because the sash has to come out, it’s time consuming and very difficult to achieve a match into product that’s been weathered”, says Iain McIntosh, Ilkley Windows.

He continues: “Installers know that or should know that. Customers are, however, also doing more and more research. The issues and the answers are there online and people are making more informed choices.”

Customer research was instrumental in a major contract, won by Ilkley Windows to supply Residence 9 to a private new build development in Sheffield. The high-end project was completed during a three month period over the summer, with Ilkley Windows completing the installation around other trades.


R9 unglazed delivers the same aesthetics as traditionally mechanically jointed windows but as its welded, it doesn’t need to be glass bonded

This included the supply of two bay windows, two arched windows, more than 20 standard casements as well as three French doors, a single door and composite doors. These were supplied in Corse Lawn and Clotted Cream finishes, while Ilkley Windows also supplied colour matched aluminium inline sliding doors and an orangery to the property.

“It was a substantial contract and we didn’t win it by being the cheapest but on the strength of our service and the supply of Residence 9 unglazed”, says Iain.

He continues: “We worked closely with the customer on all aspects of the project but they also did a lot of research into the way the windows were manufactured, choosing us over competitors because they wanted the flexibility to replace IGUs if they failed or were damaged, without the replacement of the sash.

“Being able to supply R9 in an unglazed format because we’re supplied by HWL and their manufacturing process won us the business. There’s no question about it.”


Traditional butt joints but without glass bonding


HWL Trade Frames has led the development of an R9 frame-only offer, pioneering the application of Timberweld® sash-welding technologies in its manufacture. This allows HWL to deliver a90° external and internal butt weld, emulating the appearance of a traditional timber flush casement or mechanically jointed sash.

At the same time, because it’s also stronger, the welded sash doesn’t need to be glass bonded – a process used in traditionally mechanically jointed R9 sashes to increase their structural strength.

“There’s enough weight in R9 frames without the glass in them”, says Iain “you wonder how some of these windows get installed at all when they’re glass bonded and glazed.

“For us there’s clearly a big advantage in handling unglazed frames. It’s not necessarily a faster process because you have to then glaze them but its far easier in handling and the fix.

“The benefit, however, is also there for the customer because as I said, if a unit fails a few years down the line which you would hope doesn’t – but does – happen, you can replace it in the same way as you would replace a standard unit.”


New technology fully tested


Regular weld tests completed by HWL as part of its quality control process reveal that Timberweld unglazed R9 head weld consistently stands up to up to 11 bars or 1100kN/m2of pressure. That’s consistent with a standard inline PVC-U welded product which ranges from 9-12 bars (900kN/m2 – 1200kN/m2).

In addition to its own in-house testing and conducted in partnership with the Residence Collection, the HWL window was put through its paces under PAS24 at the beginning of May by independent testing house, Exova,

This returned a series of clear passes under PAS24 test requirements for mechanical load and manual intervention testing.

These results came less than month after BS EN 6375 – 1 Weather Test results, completed in April, again by Exova. This  gave HWL’s R9 non-glass bonded window an Exposure Category of 1600, a Class 3 Air Permeability Rating (600pa); a Class 9A (600pa) Water Tightness Rating; and top Class C4 (1600pa), resistance to wind.


Traditional aesthetics inside and out


The HWL manufacturing process replicates the traditional 90° external and internal butt weld inside and out. The design of the windows and the final aesthetic forming another key driver for the end customer in the Ilkley Windows installation.

“The customer put a lot of thought into the installation and how it would work on different sides of the property”, continues Iain. “They wanted something which was fairly traditional at the front and which would complement the rest of the street scene, specifying a Clotted Cream finish.

HWL has pioneered the use of Timberweld welding technologies to manufacture an ultra-strong 90 degree jointed R9 window inside and out, without the need to glass -bond IGUs

“They specified Corse Lawn on the side and the back of the house but then Clotted Cream again on the orangery so that it would appear as if it was built separately to the rest of the house, although delivered at the same time, by contrasting with the Corse Lawn casements and aluminium sliding doors, which were powder coated to match.

“We also supplied arched windows to a gable end, as well as dormer windows. It’s quite typical of what we’re seeing. Frontages are designed to blend in with the street or road, and then you get to the back of the property and you get some really exciting designs using a large expanse of glass.”

For more information email sales@hwlwindows.co.ukcall 0113 2449006