The challenges in developing a bottom rolling multi-fold door system
Open plan living has gained popularity over the last few years. Its not hard to understand why, a multi-fold door system increases living space, light and encourages integrated living.
A practical alternative to traditional sliding doors, multi-fold doors can be used in residential and commercial applications.
Popular in residential applications in the form of expanding outdoor entertainment areas, multi-fold doors systems can also transform and upgrade commercial business including restaurants, cafes & bars.
Darley’s HarbourView multi-fold door system already came in a top-rolling version and our product designers and engineers, were eager to add a bottom rolling option to the suite to prevent the need for a load bearing lintel.
In developing this bottom rolling multi-fold system, our product designers had to bridge the knowledge gap between designing a new more standardised aluminium bi-fold, that addressed all the pain points associated with commercial bi-folds including ease-of-installation, maintenance, weight and ease of motion.
How multi-fold doors work
Multi-fold doors are made up of multiple panels on a sliding track, that can be pushed to one side with the panels folding against each other.
The majority of multi-folds are top-hung, meaning that the panels are suspended from the top guide of the frame using rollers, with most of weight concentrated in the head.
With all the weight in the head, this means the system needs adequate support in the form of a lintel. It needs to be strong enough to support the weight above the lintel, as well as the additional weight of the panels
Due to the high level of customisation, complexities in installation and high installation costs, top hung multi-folds have not been a popular choice amongst many fabricators.
Multi-fold doors are also available in a bottom rolling version. With a bottom rolling multi-fold system, there is no need for the upper beam to support the entire weight, as the bottom track carries the majority of the weight.
The challenge for Darley’s product designers was to develop an intricate bottom rolling multi-fold door system, that provides the optimal balance between water ratings, fixing screw access, extrudability, fabrication, cost and ease of use.
Another obstacle the team faced, was designing a heavy-duty multi-fold door system, that could support the weight of the panels when they are all stacked to one side.
For example, a single panel weights 50kgs – so a six-panel door stacked to one side would result in a 300kg load bearing across the head section.
Something never tried before with this type of system, the team always knew they would be faced with design challenges.
Due to the large weights having to be incorporated into the new design, this created issues with panels dragging on the track. After a number of trials were carried out to alleviate this issue, the profiles were then re-designed and the track location was moved to under the panel to maximise performance. This solved all operational issues and improved reliability in a shifting build.
This alteration created another issue – water drainage!
The new location under the panel, blocked access to the drainage holes, which are essential for draining water in storms and other extreme weather conditions.
Further design work and testing was carried out, which resulted in a new design that allowed the water to drain over the new track location. Final testing was carried out, which proved successful and after field trials the HarbourView Bottom rolling multi-fold was ready to go.
The bottom rolling multi-fold door system is now part of the HarbourView Multi-fold door range
and has been fabricated and installed by a number of fabricators in commercial applications such as cafes and RSLs.