Benefits of unglazed windows

HWL claims its non-glass bonded R9 window has been developed to make installation easier. Homeseal Windows put it to the test.

“I would never go back to installing R9 glass-bonded – there’s far too much weight in it,” Charlie Owen, managing director and owner of Homeseal Windows Yorkshire, said. “Frame-only supply means you don’t have the glass, you don’t have the weight, and it’s a much easier install.”

Working out of Hull and surrounding areas, Homeseal Windows Yorkshire was set up by Owen in 2005, supplying a range of products including Rehau, Halo, Solidor and Residence 9.

“If you’re selling R9 you’re selling into a particular type of property,” he said. “Windows are generally bigger, they’re going into bays, and that’s a lot of weight in the frames and the glass. It can easily make it a three-man job to fit them.

“With glass-bonded you also have the problem of trying to install fixed lights. It’s almost impossible. You can do it but you obviously have to work around the glass so it takes a lot of care and attention, and get it wrong and you have a real problem because you can’t just replace the unit.

“If I’m totally honest, it’s put us off supplying R9, and where we’ve been able to, we’ve switched people onto different systems unless the customer has really wanted it, because it’s so heavy and not been good to fit.”

HWL’s R9 window sidesteps all of the challenges around installation through R9 frame-only supply. It’s been able to do this through Timberweld.

This allows HWL to replicate the aesthetic delivered in a 90° mechanical joint in a welded sash, butt welding it inside and out, at the same time as delivering a significant increase in structural strength, which means the glass bonding of the sash is no longer a requirement in most configurations.

Frame-only supply delivers a number of immediate advantages at point of installation. On-site handling is easier because the product can be glazed after installation.

This also means that the challenge of securing a fix to the substrate on non-openers and sidelights are also resolved. IGUs can also be sourced by installers from their usual suppliers.

“The other thing is remedial work,” Charlie said. “If unit fails or is damaged, it’s very difficult to replace a glass-bonded window. You just replace the sash.

“If the window has been there four three or four years in the sun, the new sash isn’t going match-in. The flexibility to replace the IGU as you would on any other system is a really big advantage for the homeowner.”

The HWL unglazed R9 window has gone through a rigorous independent testing programme. BS6375-1 Weather Testing, completed in March, returned a series of top passes. It has an exposure category rating of 1600, a 9A Class rating on watertightness, a Class 4 wind load rating, and Class 3 airtightness rating.

Delivered in partnership with the Residence Collection, this was followed in May with a series of passes under PAS24 test requirements for mechanical load and manual intervention testing.

“It’s not necessarily that R9 unglazed is quicker to install because you obviously have to glaze it, but it’s far easier to install because handling is simpler and you’re dealing with less weight. I’d always go for glazing a window than handling a glass-bonded one,” Charlie said.

“For example, we’ve just installed some big bay windows in R9 from HWL. Had that been a glass-bonded window the front section alone would have easily been 150kg alone, and that would have made it a three-man job.

“Without the glass we could do it as a two-man team. That’s a big saving on cost of installation.”

He said this eliminates the negatives traditionally associated with R9 installation, leaving retailers free to get on with selling it.

“For me R9 is still head and shoulders above other systems. There are a number of flush and heritage systems available but R9 still looks the best, its performance is there, it looks great, and consumers want it,” he said.

“We’ve perhaps held back a little in promoting R9 because of the handling issues but those aren’t there anymore. Frame-only, you fit it and glaze it just like any other system.”