Why panel count and threshold choice matter more than the headline width.
Bifold prices are usually quoted per opening, but the cost inside that number is driven by panel count, material and what happens at the threshold — not simply by how wide the opening is.
Here is how the price is built, and where the genuinely worthwhile upgrades sit.
Each panel adds hardware, hinges, rollers and glass. A four-panel set in the same width as a three-panel set costs more, and it also changes the stacking pattern and the size of the clear opening you actually get.
Aluminium gives slimmer sightlines and better rigidity across wide spans, which is why most large bifolds are aluminium. uPVC can be the sensible choice on smaller openings where budget matters more than sightlines.
A low or flush threshold looks better and is more accessible, but it needs correct drainage detailing beneath it. If the opening is being widened, structural work and a lintel are a separate cost line that must be in the quote.
Send the opening width and a photo — we'll quote panel configurations side by side.
Wide spans are possible in aluminium, but the practical limit depends on the structural opening and lintel above it, which we check at survey.
Modern bifold systems use multipoint locking on the lead door and shoot bolts on the intermediate panels. Ask for the locking specification in writing.
Bifolds open the whole span; sliders give a larger uninterrupted glass area when closed. Our comparison guide covers this in detail.