All you need to know about flush thresholds
The beauty of a bifolding door is when it’s fully open, it creates a seamless transition from the house into the garden. Seamless that is, if you have a flush threshold. A threshold that juts up and has to be stepped over, is not only ugly but also a safety concern.
A flush threshold is definitely possible but how flush is flush, and what are the implications?
If you look at most of the doors, front doors, back doors, French doors and patio doors in your house, you’ll notice you have to step over the threshold. There’s no reason why most of these thresholds can’t be below the finished floor level. This in itself will go a long way to creating that seamless finish but it’s still possible to go a bit further. Both the thresholds described below can also be sunk into the floor but they have been designed with creating a seamless transition in mind.
Non rebated thresholds for your bifolding doors
1) To achieve a completely smooth and even transition from inside to out, a non rebated threshold is required, as shown in the image below. The roller sits inside the section and the flooring buts up to the top of the threshold on either side, providing a seamless transition.
The downside to a non rebated threshold is that it doesn’t come with the same level of weather protection a rebated threshold would. Perfect if the bi-fold door is in a sheltered position but not so great if it’s exposed to the full extent of the elements. Rain could run down the door and work its way inside as there is no barrier to stop it.
2) A rebated threshold provides full weather protection. The up stand (the barrier) fits tightly against the door when closed, creating a tight seal. This results in the internal level being slightly different to the external, but not to an extent where it becomes a trip hazard or is unsightly. The image below is Origins rebated threshold, it shows how a relatively flush finish (15mm difference between the two levels) can be achieved.
Being able to open a set of bifolding doors and have a flush transition is high on the list of priorities for almost all our customers. Yet we’ve found that protection from the elements is even higher on that list and thus almost 98% of all customers decide to opt for the rebated threshold.