- 13 July 2026|
- News|
- midland_admin
If you’re quoting a new extension, a garden room, or a rear elevation replacement, aluminium bifold doors are almost certainly on the specification. They remain one of the most popular choices in residential and light commercial glazing, and for good reason. Large clear openings, slim sight lines, strong thermal performance, and a wide range of sizes make them a practical and attractive solution across a variety of project types.
But getting the specification right from the outset matters. Errors in threshold selection, panel configuration, or glass spec can cost you time, margin, and credibility on site. This guide is written for trade installers who need accurate, detailed information to quote confidently and specify correctly.
Why aluminium bifold doors remain a popular choice
Aluminium bifolds have become the go-to alternative to traditional french doors and older patio doors, and they consistently outsell wooden doors and uPVC equivalents in the premium residential market. The main reasons are straightforward: aluminium frames are strong enough to support large glass panes with minimal frame depth, which means more natural light and better views of outdoor spaces.
Unlike wooden doors, aluminium requires no repainting, warping, or seasonal adjustment. Unlike uPVC, it carries a premium aesthetic that suits modern new build projects as well as renovations and garden rooms. For installers, this translates into higher average order values and clients who are generally committed to spending properly on the job.
At Midland Aluminium, we supply the Smart Systems Visofold 1000 for residential applications and the Visofold 4000 for commercial door systems. Both are manufactured from thermally broken aluminium profiles and represent a high performance solution across the full range of residential and commercial project types.
System specification: what installers need to know
Sight lines and profile dimensions
The Visofold 1000 uses 60mm thermally broken profiles, achieving inter-panel sight lines of just 132mm when panels fold and slide in the same direction. There are no additional mullions required between panels.
These slim sight lines are one of the defining selling points when presenting to clients comparing aluminium bifolds against older concertina door designs.
Panel configurations and the number of panels
Bifold door sets can be configured with varying numbers of panels depending on the width of the opening. As a general rule, more panels mean more flexibility in how the door set folds back, but also more locking points and seals to manage.
For most residential projects, a three or four panel configuration is common. Larger openings, such as those found in garden rooms or open-plan dining rooms, may call for five or six panels.
It is worth confirming with the client which side of the opening they want the traffic door on before fabrication. The traffic door is the lead door in the set and the one used for everyday access without opening the full bifold patio doors. Getting this wrong after fabrication is an expensive error.
Threshold options
The Visofold 1000 offers a choice of low threshold or weathered threshold. The low threshold option allows for a near-flush transition between interior and exterior floor levels, which is particularly useful for living space to garden continuity, room dividers, or links between a house and a new extension or conservatory. The weathered threshold provides a more robust weather seal for fully exterior bifold doors exposed to the elements.
For building regulations compliance, always verify the threshold spec against the project requirements, particularly for accessible design.
Thermal performance and glazing specifications
Thermal efficiency is increasingly important to clients and building control alike. The Visofold 1000 uses a polyamide thermal break within the outer frame, which significantly reduces heat loss through the aluminium frame itself. This is standard across the door set.
As standard, we supply 28mm clear toughened double glazing with a centre pane U value of 1.1 W/m2K. Solar control glass is also available, offering 57% heat reflection and 35% glare reduction, which is relevant for south-facing installations where solar gain can cause overheating during summer months. For projects where energy bills and energy consumption are a client concern, this is worth specifying as standard.
Integral blinds can be factory-fitted between the panes, offering a practical solution for privacy in dining rooms, bedrooms adjacent to outdoor spaces, or anywhere a clean interior look is required.
Colour options and RAL specification
Aluminium bifolds are available in a wide range of RAL colours, with dual colour options allowing different finishes on the interior and exterior. Standard stock colours carry lead times of 2 to 3 weeks. Bespoke RAL colours are available to order.
Handles come as standard in white, chrome, or black. RAL-matched handles can be specified at extra cost, but note that the traffic door handle style will differ from standard when RAL colours are selected. Brief clients on this at the quoting stage to avoid surprises.
Trade pricing: how it works at Midland Aluminium
We supply on a trade basis, with pricing structured to support installers quoting competitively in the market. Pricing varies based on overall dimensions, number of panels, colour specification, and glass choice.
To get an accurate trade price for a complete bifold door set, send us your full specification including:
- Overall width and height of the opening
- Number of panels and fold direction
- Traffic door position and opening side
- Threshold type
- Colour requirements (interior and exterior)
- Glass specification
We turn quotes around within 24 hours. There is no minimum order value, and delivery is free to mainland UK postcodes on our weekly national routes.
Common specifying pitfalls to avoid
- Getting the traffic door position wrong. Confirm this with your client before ordering as it cannot be changed after fabrication.
- Underspecifying on threshold type. A low threshold fitted to a fully external application with no shelter above it will struggle to meet weather performance expectations. Match the threshold to the exposure level.
- Ignoring solar gain. South or west-facing installations without solar control glass can create uncomfortable living spaces in summer. Flag this to clients at the design stage.
- Vague sizing. Always provide the outer frame dimensions, not the structural opening, and confirm the installation tolerances required.
Frequently asked questions
What is the lead time for aluminium bifold doors?
Lead times start from just 7 days for bifold doors in standard configurations. Bespoke RAL colours or non-standard sizes may add time. We will confirm lead times at the point of quoting so you can plan your installation schedule accurately.
Do you supply to trade only?
Midland Aluminium primarily supplies trade customers including installers, builders, and developers. We work across the whole of the UK and offer free delivery nationwide with no minimum order.
What U value do your bifold doors achieve?
Our standard double glazing package achieves a centre pane U value of 1.1 W/m2K. Triple glazing is available for projects requiring higher thermal efficiency.
Can bifold doors be installed in a conservation area?
Aluminium bifolds can be suitable for conservation areas depending on local authority guidance. We would recommend checking with the relevant planning authority before specification. Our heritage aluminium range may also be worth considering for sensitive locations.
Are integral blinds available?
Yes. Integral blinds can be factory-fitted between the panes on bifold door sets, providing a clean finish without the need for separate blind installation.
Get a free trade quote from Midland Aluminium
If you are specifying aluminium bifold doors and need accurate pricing and lead times to quote a project, we are ready to help. Send us your specification and we will have a trade quote back to you within 24 hours.
Get in touch via our online contact form or call us on 01785 287907.
Choose Midland Aluminium for fast quotes, honest pricing, reliable delivery.