Aluminium Bifold Doors — Complete Buying Checklist

Step 1 — Confirm Planning and Regulatory Position

Before measuring, specifying, or approaching any supplier, confirm whether your installation requires planning permission or building regulations approval.

Check these items:

Is the property listed? If yes, Listed Building Consent is required before any work. Consult a conservation architect before specifying any system.

Is the property in a conservation area? If yes, confirm with your local planning authority whether the proposed installation requires consent. Rear elevations not visible from a public road are generally less restricted.

Is the opening new or existing? Replacing an existing opening is almost always covered by Permitted Development rights. A new opening created as part of an extension follows the planning status of the extension itself.

Does the property have Article 4 Directions? These remove Permitted Development rights from specific properties or areas. Check with your local planning authority if uncertain.

Is a building regulations certificate required? Replacement doors in existing homes are self-certified by a FENSA-registered installer automatically. New extensions requiring building regulations approval need a FENSA certificate or local authority building control sign-off.

Step 2 — Assess the Opening

Measure and record the following before approaching any supplier. A supplier who gives you a firm price without visiting the opening is either guessing or planning to adjust the price after commitment.

Measure these:

Clear opening width — measure between the finished reveals on each side, not between brickwork. This is the dimension the door system fills.

Clear opening height — from the finished floor level to the underside of the lintel. Check this at both ends of the opening. If the figures differ, note the smaller dimension.

Floor level difference — measure the height difference between interior floor level and exterior ground or patio level at the threshold position. This determines threshold type.

Lintel span and condition — confirm a structural lintel is in place spanning the full width of the opening. If the opening is new and the lintel has recently been installed, confirm with your builder that it has settled before booking a survey.

Stacking space — measure clear wall space available alongside the opening on one or both sides. Approximately 300mm per panel is required.

Step 3 — Choose Your Configuration

Work through these decisions in order — each one affects the next.

Panel count: Divide your clear opening width by 1.0–1.2 metres to get the approximate panel count. Confirm the resulting panel width is within the system’s maximum panel width specification.

Traffic door: Do you need everyday access without opening the full system? If yes, specify an odd-numbered panel count — 3, 5, or 7 panels. If the door is primarily used for entertaining and occasional access, an even-numbered count is fine.

Opening direction: Inward or outward? Outward requires clear exterior space. Inward requires clear interior space behind where the panels stack. Most UK residential installations open outward.

Stacking direction: Left, right, or split? Confirm which sides of the opening have clear stacking space. Master stacking sends all panels to one side. Split stacking divides them equally to both ends.

System choice:

Step 4 — Specify Glazing and Threshold

Glazing:

Standard double glazing with argon fill is appropriate for most UK residential locations. Confirm the whole-door U-value meets Part L’s 1.4 W/m²K maximum for your chosen system and glass specification.

Consider solar control glass for south or west-facing openings where summer overheating is a risk.

Consider laminated glass if security is a priority — it holds together under sustained attack in a way that toughened glass alone does not.

Specify triple glazing only if the installation is in a north-facing, very exposed, or high-performance building context. The F80 IconiK achieves 1.0 W/m²K with triple glazing. The F82 Luminia achieves 0.9 W/m²K.

Threshold:

Rebated threshold — standard choice for most residential installations. Small step. Best weather resistance.

Low-rise threshold — reduced step height. Suitable where minimising the step is desirable but full level access is not required.

Level threshold — no step. Complies with Part M accessibility requirements. Requires careful management of interior and exterior floor levels.

Weathered threshold — deeper rebate for exposed or coastal locations where weather penetration resistance is the priority.

Step 5 — Confirm Colour and Hardware

Frame colour:

Single colour or dual colour? Dual colour — different interior and exterior finish — adds cost but allows the exterior to match the architectural language of the building while keeping the interior finish light and neutral.

Confirm the RAL number in writing with your supplier before order. Request a physical colour sample or reference an installed example before committing to a colour.

Most popular exterior colours: RAL 7016 Anthracite Grey, RAL 9005 Jet Black, RAL 8022 Black Brown.

Most popular interior colour for dual: RAL 9016 Traffic White.

Hardware:

Confirm handle style and finish. Standard handles are typically aluminium or stainless steel. Premium finishes (brushed brass, bronze) are available at additional cost.

Confirm the locking mechanism includes multi-point locking and shoot bolts as standard.

If PAS 24 is required, confirm in writing that the system and hardware combination is fully PAS 24 certified — not just PAS 24 capable.

Step 6 — Evaluate and Compare Quotes

Never accept a quotation given without a home survey of the opening. Firm prices require confirmed measurements.

When comparing quotes, check these items:

Is the survey included at no charge? A reputable installer surveys before quoting. Any company quoting on customer-supplied dimensions is not providing an accurate price.

Are all quotes based on the same system and specification? A quote for BSF70 and a quote for F82 Luminia are not comparable. Ensure like-for-like comparison.

Does the price include removal and disposal of the existing installation? This should be included as standard.

Is the FENSA certificate included? It must be. Any installer who charges separately for the FENSA certificate is adding a cost that should be standard.

What does the guarantee cover? Request the guarantee terms in writing. Confirm it covers thermal performance and weathersealing — not just hardware.

Verify the FENSA registration number before appointing. Check it at fensa.org.uk/homeowners/fensa-certificate-and-consumer-protection/check-a-fensa-company. An unregistered installer cannot issue a FENSA certificate.

Step 7 — Prepare for Installation

Complete these items before installation day.

Structure:

Confirm the lintel is fully settled and structurally sound with your builder. Do not book installation against a freshly installed lintel.

Confirm the reveals are plastered or finished to their final state. Door frames cannot be accurately fitted against unfinished reveals.

Confirm the exterior ground or patio level is at its finished height at the threshold position. The threshold type and fitting depends on the final level differential.

Access:

Clear furniture and floor coverings back from the opening area inside. A minimum of 1.5 metres of clear working space inside is needed.

Ensure the exterior is clear of plants, furniture, or stored items within approximately 2 metres of the opening.

If scaffolding or access equipment is needed for a high installation, confirm it is arranged before the installation date.

Flooring:

If new flooring is being laid near the threshold, discuss the sequence with your installer before installation day. The threshold height affects the finished floor level — laying flooring before the threshold is confirmed risks getting the junction wrong.

Step 8 — Installation Day

Stay on-site or have a responsible adult present throughout the installation. Before your installer leaves, check every item on this list.

Frame:

• Frame is level — check visually at head and both jambs
• Frame is plumb — no visible lean on either side
• Frame is sealed at perimeter — no visible gaps between frame and reveal

Panels:

• Every panel opens and closes smoothly through full travel
• No panel drags on the track at any point
• Panels stack cleanly without fouling each other or the wall

Seals and threshold:

• Perimeter seals compress evenly around the full frame — no visible gaps when closed
• Threshold is level and sealed — no gaps between threshold and floor finish
• Drainage slots in threshold are clear and unobstructed

Locking:

• Every locking point engages cleanly — no stiffness, no misalignment
• Shoot bolts engage at head and foot without forcing
• Key operates smoothly from both inside and outside

Documentation:

• FENSA certificate received
• Product documentation and data sheets received
• Guarantee terms received in writing
• Installer’s contact details confirmed for aftercare

Step 9 — After Installation

Immediately:

Register the guarantee with the manufacturer if required — check the product documentation. Some manufacturer guarantees require online registration within 30 days of installation.

Keep the FENSA certificate, product documentation, and guarantee paperwork in a safe place. These are required at point of property sale and may be needed for insurance claims.

At 6 months:

First maintenance service — clean and lubricate tracks and rollers, check panel alignment, lubricate all locking points and hinges. This is the most important single maintenance action for a new installation as rollers settle into their running position during the first months of use.

Annually:

Full annual check — panel alignment, seal condition, glazing seals for misting, threshold seal for wear, all locking points tested. One hour per year maintains the system in good condition for its full service life.

For full detail on any item in this checklist, read our complete aluminium bifold doors handbook. To book a free survey, contact our team.

French doors are two door leaves — a pair of hinged panels that swing outward or inward from a central meeting point. They open like any hinged door, just in pairs. A standard French door pair covers an opening of approximately 1.2 to 1.8 metres. For wider openings, French doors are combined with fixed side panels — but those fixed panels remain in the aperture permanently and reduce the effective opening width.

Bifold doors fold concertina-style on hinges connecting each panel to the next. All panels travel along a bottom track and stack to one or both sides of the opening. The full width of the aperture becomes clear. For a 3-metre opening, a 4-panel bifold gives you 3 metres of clear access. A French door on the same opening, with fixed panels to reach 3 metres, gives you approximately 1.5 metres of actual access.

This mechanical difference is the starting point for almost every other comparison that follows.