Schüco bifold doors: what to check before you order

A folding door is the only thing in a domestic build that is simultaneously a structural opening, a piece of precision machinery and a large sheet of glass you are expected to walk through twice a day. It rewards being thought about early. Almost every complaint we hear about Schüco bifold doors turns out, when you trace it back, to be a decision someone made in ninety seconds during a survey visit.

What follows is the checklist we would want a homeowner in Barnet or Hertford to have in front of them before signing anything.

First, work out which system you are being quoted

Schüco — spelled Schuco on plenty of quotations, umlaut or no umlaut — is a systems house, not an installer. It designs the aluminium profiles, extrudes them, and sells them through fabricators who cut, machine, glaze and fit the finished doors. So when three companies in St Albans quote you for Schüco bifold doors, all three are working with the same extrusions. The metal is not the variable.

The folding system you will usually be offered for a house is AS FD 75 — a 75 mm deep, thermally broken profile aimed at residential openings. There are other options in the wider range, including slimmer and heavier-duty variants, but if a quote just says "Schüco bifold" without a system code, ask. It takes one email and it tells you whether the person quoting knows their own product.

Leaf width is the first real decision

Divide your opening by the number of leaves and you get the leaf width. Fewer, wider leaves mean less frame in the view when the doors are shut. More, narrower leaves fold into a smaller stack when they are open.

Most fabricators cap leaves somewhere around 1,000–1,200 mm wide and roughly 100 kg including glass, though the exact limit belongs to the fabricator rather than to Schüco and varies with configuration. Push toward the top of that range and two things happen. The doors feel heavier in the hand — noticeably so, if the person using them is small or elderly — and the hinges work harder for the next twenty years.

Our rule of thumb: for a typical 3 m rear opening, three leaves is the sweet spot. Four gives you a chunkier stack for no real gain. On a 4 m opening, four leaves at roughly 1 m each is comfortable, and three at 1.33 m starts to feel like a gate.

Stacking: which way they fold, and where the stack lands

A folding set can be configured to stack all to the left, all to the right, or split — say two panels each way. The stack sits perpendicular to the opening, sticking out into the room or out onto the terrace, and it is bulkier than people expect: four leaves folded is easily 400–500 mm deep.

Walk the space before you decide. Things that ruin a stacking choice:

• An external tap, downpipe or meter box exactly where the doors want to sit
• A kitchen run or island that the internal stack now clips
• A side return path that becomes unusable when the doors are open — common on the narrow Victorian returns in Muswell Hill and Crouch End
• Prevailing wind. An open stack is a sail. If your garden funnels wind from one side, stack away from it

Stacking externally keeps the room clear but leaves the doors exposed to weather when they are open, and means the terrace needs enough depth. Internal stacking protects the doors and eats floor area. Neither is wrong; both are permanent.

The traffic door question

A traffic door — sometimes called an access leaf — is one panel hinged to open on its own, like a normal door, without folding the set. It is the single most useful option on the list and the one most often dropped to save money.

Without it, letting the cat out in February means unlocking and folding back a whole leaf. Households that installed a bifold set without a traffic door and use it as their main garden route almost always tell us they would pay for it next time. The cost is modest, the penalty is a slightly wider profile at that junction and a set that is no longer perfectly symmetrical.

The exception is a set that is genuinely secondary — a dining room that opens onto a terrace three times a summer. There, skip it.

Threshold, and what happens underneath

You will be offered a weathered threshold with an upstand, or a low or flush threshold that sits close to level with the floor. Flush looks superb, particularly when internal and external floor levels are continuous, and it is the right answer for accessibility. It is also the detail that most often leaks when it is done casually.

A flush threshold works when there is proper drainage in front of it: a linear channel or a gravel strip, falls running away from the house, and a damp-proof detail that has been thought about rather than improvised. On the clay soils common across Hertfordshire, standing water at a door line is not hypothetical. We go into this properly in the guide to thresholds and building regulations.

Colour, and the two-tone trap

Powder coating comes in the full RAL range. Anthracite grey (RAL 7016) is on perhaps two thirds of the doors we see, followed by black and off-white. Dual colour — one shade outside, another inside — is available and adds both cost and lead time, because the profile goes through coating twice.

Two small warnings. Matt finishes show fingerprints and hard-water marks more than satin, which matters in Hertfordshire's water. And if you are matching to existing windows coated five years ago, expect a visible difference; batches drift, and gloss level drifts faster than colour.

What should be written on the order

Before you sign, the paperwork should state, in writing: the system name and profile depth; the number of leaves and the stacking configuration, drawn; whether there is a traffic door and which side it hinges; the threshold type; the glass specification including unit thickness, coating and whether it is toughened or laminated; the RAL number and finish; the whole-door U-value being claimed; the handle and lock type; and who is responsible for making good internally and externally.

If you want to see how manufacturers present these options themselves, it is worth reading a fabricator's own technical pages alongside your quotes — Schüco folding door systems are documented with the configuration and sizing information you can then check your quotation against. Comparing the two is a fast way to spot a quote that has been written from a template rather than from your opening.

Common questions