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Alexandra Giles

Alexandra works in the marketing department, and in 2014, bought her first house, which turned out to be somewhat of a ‘project’. Since then, the whole house has needed renovating, which has helped her gain a knowledge of basic DIY, decorating and making the best of a small space.

By Alexandra Giles

Thresholds are a key feature of bi-folding doors. Clients are demanding lower, more flush thresholds to allow the inside and outside worlds to meet seamlessly, in an attempt to move forwards from more traditional large obstructive thresholds that require a step over – something that’s previously been associated with older French and single doors.

At Origin, we offer a selection of threshold options for our bi-folds, French and single doors that can offer this seamless way of living. However, bi-fold doors do not come with a one size fits all threshold and present some considerations to think about when specifying or installing bi-fold doors.


In this guide:

What is a bi-fold door threshold?

Find out more about what a bi-fold door threshold is and how it works.
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Threshold options from Origin

Learn more about the threshold options available when supplying Origin Bi-fold Doors.
READ MORE

Supplying Origin bi-fold doors

Find out more about what you can expect when supplying Origin Bi-fold Doors.
READ MORE


What is a bi-fold door threshold?

The threshold of a bi-fold door is its bottom track. It the bottom frame in which the doors sit in and is installed on the top of the floor’s foundation. It can often have a cill installed onto it, but this is not always necessary depending on what drainage option has been specified.

Thresholds are designed to provide weather resistance by preventing the elements from penetrating through and leaking into the home. Choosing the correct bi-fold door threshold for a project will mean considering the threshold type (weathered or non-weathered), and whether it can be recessed to minimise the transition between the inside and out and the drainage – all to ensure that the bi-fold door will offer optimum weather proofing for the homeowner.

It’s important to understand the bi-folding door threshold options available before specifying bi-fold doors to make sure they function correctly and provide the right amount of protection.


Threshold options from Origin

Origin Aluminium Bi-fold Doors are available with both weathered and non-weathered thresholds. A mobility threshold is also available from Origin, but this is only available on single and French doors, so we’ll focus on the weathered and non-weathered throughout this article. Although both of these options both present their benefits, we want to make sure that you feel confident in choosing the right option for your needs, so we have provided more details below:


Weathered thresholds

A weathered (or rebated) threshold includes an upstand on it, so that when the doors are shut, the gaskets and door seal tightly against it. These thresholds come with a weather rating and are effective at keeping out the elements and providing reliable protection from the weather.

Height

Whilst weathered thresholds provide many benefits, the height can be an issue for some homeowners. Due to the rebate which allows bi-fold doors to seal tightly against it, the height of a weathered threshold is 68mm. However, the track can be recessed into the floor, leaving just the 14mm upstand externally and an 8mm lip internally.

Where to use a weathered threshold

Because of its weather rating, these weathered thresholds are recommended for use in doorways that separate the inside and outside areas of the home in order to provide weather protection and ensure that rain is kept out of the home. Many clients opt for this option as it gives the reassurance that their home will be weather protected for the sake of a 14mm lip.

Non-weathered thresholds

The second threshold option, and the one that provides the most seamless transition between spaces of the home, is the non-weathered, or flush, threshold.

These thresholds do not include a rebate in the same way as weathered thresholds, meaning that they do not carry a weather rating and draught-proofing cannot be fully guaranteed as a result of their lack of seal at the bottom of the bi-fold doors.

However, this threshold creates no step between the inside and outside, providing a truly seamless transition between areas of the home.

Height

Flush thresholds have a lower height than weathered thresholds, as it’s 50mm. Although this comes at the sacrifice of greater weather protection and draught-proofing, it brings with it the benefits of a seamless living space free of hazardous steps at the door threshold.

Where to use a flush threshold

A flush threshold is usually recommended for sheltered exterior spaces such as patios or conservatories, or internal uses.

This mitigates the drawbacks of the flush threshold, meaning that they are less likely to be tested by the elements and leaves homeowners with only the benefits to enjoy.

Popular options for the use of flush thresholds include doorways to conservatories, which allows for a free and smooth transition to the most open part of the home. Flush thresholds provide a level step which allows for easier movement between rooms of the house.

Rebated threshold detail with concealed drainage
Flush threshold bottom track detail
Non weathered threshold detail

Cills

Both weathered and non-weathered thresholds are able to be specified with a cill, which is made from the same grade aluminium as our bi-fold doors. Cills act as an extrusion and can help project and channel water away from the brickwork underneath the frame and aid drainage. There are 4 lengths available – 95mm, 155mm, 180mm and 225mm.The 225mm cill will always need to have face drainage. With all cills, these can be powder coated to be the same colour as the doors.

Supplying Origin Bi-fold Doors

Origin Aluminium Bi-fold Doors and their thresholds have been thoroughly researched and designed to ensure that they function optimally so you can be assured that the Origin Bi-fold Doors you supply are fit for purpose and will provide a long-term solution.

We will provide full product training to help you understand how each element of the bi-folding door works, how it should be specified and how it should be installed.

For further information or if you have any other queries, please contact our team to find out more.