Bi-fold doors: Budget, safety and security tips

Follow expert advice on cost and safety considerations before you buy your folding sliding doors

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How much do folding sliding doors cost?

The budget for a bi-fold door varies from £1,200–1,600 per linear metre plus VAT for the doors including installation. The price will vary according to the specification you choose for your home. For more information on bi-folding doors, visit 

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Will I have to pay upfront for the doors?

Never pay in full on order. If you’re having the system supplied and installed, payment is normally a deposit with the order, with perhaps an interim payment depending on the size of the order and a payment on completion of installation. Where it is supply only, it is much the same, but some companies ask for a deposit and then the final payment prior to delivery.

What security features should I be looking for?

Security should not be a concern with bi-folding doors even if you’re installing large expanses of glass in bi-folding doors. Just ensure the doors have a locking system that meets the police preferred ‘Secured By Design’ standards.

Choose a manufacturer that includes accredited, insurance-recognised locks – at least a five-lever key cylinder – as standard. The weakest point of a locking system is often the cylinder, so look for cylinders that are resistant to snapping, picking, drilling and bumping. Good-quality products have integrated multipoint locking systems, with hooked locks and shoot bolts.

The police are raising awareness of door lock security as part of their ‘Secured By Design’ initiative, working with BSI (the UK’s national standards body) to create a new cylinder with extra protection, indicated by a Kitemark alongside three stars.

The quality of doors and hinges is an important factor in security, as is ensuring the frame is firmly fixed to the walls. It’s worth looking for an internally glazed system, as with an externally glazed design it may be possible to remove the beads and double glazing from outside to access the property.

In addition to security, check out the operation of the doors to make sure they are simple and reliable to use. If the system seems fiddly or clunky, look elsewhere.

Adding bespoke blinds will give extra privacy if needed

What to consider before you buy:

  • Building Regulations — units must be double-glazed, with toughened or safety glass, and need a U-value of 1.8W/m²K or less and a Window Energy Rating (WER) of at least C.
  • Low-e (low-emissivity) glazing — look for units that fill the gap between the panes with an inert gas, such as argon.
  • Base track systems, where doors are floor-supported, can prove less disruptive as they may require nothing more than a timber lintel. Top-hung systems use gravity to ensure ease of use, but need a steel support to take the weight of the doors.
  • Include an access door so that you can enter or leave without opening the entire system.
  • Ensure units are fitted with high-security hinges and internal locking shoot bolts that lock into the frames by at least 24mm.

Featured image: Made from timber and aluminium, the triple-glazed SL97 system from Solarlux has one of the lowest U-values in the UK — only 0.8W/m²K. A patented construction with a layer of insulation between the wood and aluminium ensures excellent thermal performance. Prices start from £9,995 for a (H)210x(W)300cm panel set, excluding installation