From June 2022, replacement doors with a >60% glazed area will need to achieve an overall U-value of 1.4W/m2K, while newbuild equivalents will need to achieve an overall U-value of 1.2W/m2K.
When the Future Homes and Buildings Standard comes into force in 2025, these figures are expected to drop even further.
Since the revisions were announced in December 2021, many fabricators have been turning to their suppliers to see if their systems can accommodate the revisions. In many cases introducing a triple glazed unit is one design hack.
“Older systems were designed for a double-glazed unit, so there’s a maximum width of unit you can get into the frames,” Wayne Richards, Deceuninck Aluminium’s technical manager, said. “So, the question is not about the number of panes of glass, but how deep you can go, and with older systems you are typically limited to a 28mm-32mm unit.”
If a triple glazed unit was used to improve the thermal performance, consideration would also need to be made for the extra weight placed on the hardware.
“Most bifolding doors on the market have a maximum weight of 100kg-150kg,” Wayne said. “So, if you are going to put in triple glazing then you are probably going to go over that maximum weight, which is going to limit the size of the door.
“We may be looking at acoustic/laminate glass in the future, especially with security,” Wayne continued. “You are already looking at laminate glass being installed in all doors. So, if you want to keep the size, and incorporate a 62mm unit, then you need a heavy-duty roller and hinges to cope with it.”
The Decalu88 Bi-Folding Door from Deceuninck Aluminium can comply with the 2022 Part L newbuild revisions with a double-glazed unit. It is also designed to comfortably incorporate thicker and heavier units to meet future thermal, acoustic and security standards.
“If I was a fabricator, I’d be asking my supplier if their doors can do the same,” Wayne said.
Another retrofit design is the thermal break, with some suggesting that this can be swapped out for a better thermally performing alternative.
“Systems are tested with a particular thermal break,” Wayne said. “So, if you introduce a new thermal barrier, then you have to go through the whole design and testing procedure again.
“It’s a lot easier to actually redesign a new product, especially since people are looking for slimmer sightlines and better security.”
For more information call 01249 816 969, email email@example.com or visit www.deceuninck.co.uk