An aluminium bifold door threshold is the cill along the bottom of the frame, and on a folding door it does more work than on most doors: it guides the panels as they fold and it keeps rain out when they are closed. The Coetz™ Vista Duo and Vistafold ranges offer four bottom options, and the choice is made when you order, so it pays to understand them before the floor is finished. This guide explains each option, the trade-off between a weather seal and a flush floor, and how to plan the opening.
In this guide
What the threshold does
The bottom of a folding door has three jobs. It carries or guides the panels as they concertina open, it gives the seals something to close against, and it sheds water away from the room. A raised cill does the last job best; a low cill is easier to step over. Every aluminium bifold door threshold is a balance between the two.
Aluminium bifold door threshold options
| Option | What it suits | Weather |
|---|---|---|
| Standard cill | Most openings, including those facing the weather | The standard weather choice |
| T-Track | An alternative track profile | Ask us for the detail |
| E-Track | An alternative track profile | Ask us for the detail |
| Low profile cill | A near-level step between rooms or under cover | Not weatherproof |
The same four options apply to Vista Duo and Vistafold. The low profile cill is priced per metre on top of the door. If you want to compare the T-Track and E-Track profiles, ask us for the manufacturing detail before you order.
Weather seal or flush floor?
A low cill looks clean and is easy to step over, but the price list marks the low profile option not weatherproof. Wind-driven rain can get under it, so choose it only where the door is sheltered: a deep covered patio, an enclosed courtyard, or a door between two rooms. If the opening faces open sky or a prevailing storm direction, choose the standard cill and accept a small step. When choosing an aluminium bifold door threshold, that rule matters more than looks. The same caution applies to aluminium bifold louvre doors, which are not weatherproof either.
The panels stack to the outside
Vista folding doors stack to the outside: when you open the door, the panels fold out and stand against the side of the opening on the outside. Plan for it:
- Keep paving level and clear where the stack will stand.
- Leave space for pot plants, braais and furniture so they do not block the fold.
- Make sure the outside surface falls away from the door, so water drains off rather than towards the aluminium bifold door threshold.
For where the stack sits on each layout, see aluminium bifold door configurations.
Planning the floor
Your builder should know which aluminium bifold door threshold you have chosen before the screed and tiles go down, because it changes how the floor meets the frame. Three points to agree:
- Finished floor level inside and out, so the cill sits where you expect.
- A level base across the full width. A folding door runs best on a true, level cill, and a twisted opening makes panels bind.
- Drainage outside, with a fall away from the door.
Panels are limited to 900 mm wide; Vista Duo panels go up to 2 400 mm high and heavy-duty Vista panels up to 3 000 mm. See aluminium folding door sizes.
Keeping the track and cill clean
Grit is the enemy of a smooth fold. Vacuum the aluminium bifold door threshold and track every few weeks, wipe with mild soap and water, and clear leaves after storms, especially on a sheltered low profile cill where debris collects. A clean track also helps the hook lock catch; see aluminium bifold door locks.
Ordering
The threshold is part of the door configuration, so choose it with the range, size and stack direction. Coetz™ supplies aluminium folding doors with the cill you choose; your builder or installer fits the door. We deliver across South Africa, or you can collect free from Laser Park. Every glazed panel uses 6.38 mm clear laminated safety glass, which must meet SANS 10400-N, published by the South African Bureau of Standards. See all aluminium folding doors, or compare with sliding doors vs folding doors.
Aluminium bifold door threshold: frequently asked questions
Can I get a flush threshold on an aluminium bifold door?
Yes, a low profile cill is available, but it is not weatherproof, so use it only under cover.
Which threshold should I choose for an exposed opening?
Choose the standard cill rather than the low profile cill, and accept a small step at the door.
Do Vista folding doors fold inwards or outwards?
The panels stack to the outside, so plan clear, level paving where they will stand.
When do I choose the threshold?
At the time of order, together with the size and configuration, because the door is made to suit it.
How do I keep a folding door running smoothly?
Vacuum the track and cill regularly and wipe them with mild soap and water so grit does not build up.
Coetz™, Unit 2, 84 Ridge Road, Laser Park, Johannesburg. Call 010 412 0062, WhatsApp 076 613 4418 or use our contact page.
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