Bifold Doors in
South Wales —
Modern, Slimline,
Made-to-Measure
Love open-plan living but hate bulky doors? Our bifold doors fold neatly away, flooding your home with light and creating seamless transitions from inside to out. Whether you’re entertaining guests or enjoying a quiet morning, these doors bring space, light, and flexibility to your lifestyle.
Modern bifold doors are neither cold nor easy to break into, and the engineering is the reason why.
Ours use thermally broken aluminium with a polyamide thermal break through the frame, warm-edge glazing and a U-value of around 1.4 W/m²K, so the wall of glass stays warm in a South Wales winter. On security they are built to PAS 24, with anti-lift blocks, multi-point locking and the option of laminated glass, which puts them on a par with any other external door we fit.
So the two things people worry about, that bifolds are draughty and that they are a soft spot for burglars, simply do not hold for a properly specified door. With that settled, the rest is about getting the design right: how many panes, which way they fold and stack, the threshold, and aluminium against uPVC. This page covers all of it, with a guide price near the end. If you already want to open up the back of the house, you can book a free survey and we will design it around your opening.
- Thermally broken aluminium with a polyamide break and warm-edge glazing gives a U-value of around 1.4 W/m²K, so a well-made bifold is not cold.
- Built to PAS 24 with anti-lift blocks, multi-point locking and laminated glass options, so security matches a good front door.
- Choose 2 to 7 panes; 3, 4 and 5 pane runs are the most common, with a traffic door for everyday use without folding the whole set back.
- Low, weathered and Part M level thresholds are available for flush, step-free access.
- Aluminium suits wide spans and slim sightlines; uPVC suits tighter budgets on smaller openings.
- Fitted to Part L standards by our FENSA-registered teams across Cardiff, Caerphilly, Penarth and the Valleys, with a written guarantee.
Book a free home survey and we will measure your opening, advise on panes and thresholds and give you a fixed price for a warm, secure bifold.
Are bifold doors cold and
draughty in winter?
Not the ones we fit. The old reputation comes from thin, single-glazed frames with no thermal break, where the aluminium carried cold straight through to the inside and condensation ran down the glass. Modern doors are a different product. The frame is split by a polyamide thermal break, a non-conductive barrier that stops heat crossing the metal, so the inside face stays warm and dry.
Add double or triple glazing with a warm-edge spacer, argon fill and a low-emissivity coating and the whole door holds a U-value of around 1.4 W/m²K, which sits comfortably inside Part L for a replacement. Brush and compression seals at every joint close the draughts, and when the doors are locked the multi-point gearing pulls each pane tight into the frame. Shut on a cold night, a good bifold feels solid and warm, not like a folding screen.
Aim for around 1.4 W/m²K or lower for the whole door, glass and frame together, and remember the lower the number the better the insulation. Some suppliers quote the glass alone, which flatters the figure, so ask for the whole-door U-value. If the room is north facing or you simply want the warmest option, a triple-glazed unit brings the number down further. We quote the real whole-door figure so you can compare like for like.
Complete doorset — not just a strong-looking frame
How secure are bifold doors?
As secure as a good front door, which surprises people who assume a folding door must be the weak link. The vulnerable point on any folding system is where the panes meet and where they sit in the track, so that is exactly where the security is concentrated. Anti-lift blocks stop the panes being jemmied up and out of the running track, which is the classic attack on cheap bifolds.
On top of that the doors run a multi-point locking system, with shootbolts and hooks engaging the frame top and bottom, and the main traffic door takes a cylinder to the same standard as the rest of our doors. Specify laminated glass and the pane holds together even when struck, so it cannot be knocked through quickly and quietly. The complete door is tested to PAS 24, the enhanced security standard, as a set rather than as a strong-looking frame.
Panes, made to measure
How many panes should you have?
It depends on the width of your opening and how you want to use the space. Bifolds run from 2 to 7 panes, but 3, 4 and 5 pane sets cover most homes. As a rough rule each pane is around 0.5 to 1 metre wide, so a typical 3 metre opening suits three or four panes and a wider rear extension suits five.
Just as important is the configuration: which way the doors fold and which side they stack. You can have them all fold one way, split to stack both sides, or include a traffic door. We set this out on the survey against your furniture, the view and where you walk through most, because the right stack makes the room feel bigger and the wrong one leaves a pile of glass in your path. If your opening is narrow or your budget is tighter, our patio & sliding doors may open the space more neatly.
A traffic door, sometimes called an access door, is a single pane within the run that opens on its own like a normal door, so you can nip out to the garden without folding the whole set back. It is worth having on any door you use daily, because you would not concertina five panes just to let the dog out. On a sunny day you still fold the lot away and lose the wall entirely.
What threshold options are there for level access?
The threshold is the strip you step over at the bottom, and it is a genuine trade-off between weather resistance and easy access. A standard weathered threshold gives the best defence against wind-driven rain, which matters on an exposed rear elevation. A low or Part M compliant threshold sits almost flush with the floor for step-free access, which suits wheelchairs, pushchairs and anyone who does not want a lip to trip on.
Where you want an indoor and outdoor floor to read as one continuous surface, the low threshold is the way to do it, and we can set it into the floor build-up so the finished levels line up. On very exposed sites we will talk through the weathering implications honestly so you choose with your eyes open, rather than fitting the lowest threshold and leaving you to mop up after a storm.
Aluminium or uPVC bifold doors?
Aluminium is the material most people picture when they think of bifolds, and for good reason. It is strong enough to carry large panes on slim sightlines, so you get more glass and less frame, and it takes a durable powder-coated colour finish that does not fade or need painting. For a wide opening on a rear extension, aluminium is usually the right call.
uPVC bifolds are a lower-cost route and can work well on smaller openings, though the frames are chunkier and the maximum sizes are more limited. If budget leads the decision, uPVC gets you the folding-door effect for less. If span, slim frames and long-term looks lead, aluminium earns its higher price. We fit both and will give you an honest steer for your opening rather than pushing the dearer option by default.
Both types are available thermally broken and to PAS 24 with warm-edge glazing. We fit both and will give you an honest steer for your opening rather than pushing the dearer option by default.
Bifold vs sliding vs French doors: which is right for you?
All three open the back of your house to the garden, but they do it differently and the best choice depends on how wide the opening is, how much you fold away and how much you want to spend. Bifolds concertina almost the whole wall away, which is the most dramatic opening, but they leave stacked panes to one side and cost more. Inline sliding doors glide behind each other on slim frames, keep more of the view when shut because there are fewer frames, and need no swing space, though one panel is always fixed. French doors are the simplest and most affordable, ideal for openings up to around 1.8 metres, but they swing into the room or garden and give the smallest clear opening.
Choose bifolds to open a wide span fully, choose sliders for the best glass-to-frame view and a flush look, and choose French doors for a smaller opening on a tighter budget. Compare the alternatives on our patio doors page, and if you are extending or replacing a tired lean-to, see how the doors work with our conservatories before you decide.
Concertina almost the whole wall away. Best for wide spans where you want the maximum clear opening on warm days.
Glide behind each other on slim frames. Fewer vertical frame lines mean a cleaner view when shut, and no swing space needed.
Ideal for openings up to around 1.8 metres. Simple, reliable, and the most affordable of the three options.
People forget that a bifold shows more frame when shut than a slider, because every pane has its own frame at each edge. If you spend more time looking at the doors closed than open, which is most of a Welsh year, a sliding door can give you a cleaner view, while a bifold wins on the full-width opening for those warm weekends. It is worth being honest with yourself about how you will really use the room.
How much do bifold doors cost fitted in Cardiff or Caerphilly?
As a guide, a supplied and fitted aluminium bifold runs from around 3,000 to 6,500 pounds depending on the width, the number of panes, the glazing and the threshold. A three-pane uPVC set on a modest opening sits at the lower end, while a wide five-pane aluminium run with triple glazing and a flush threshold reaches the top. The figure includes removing the old doors or wall opening finishes, fitting the frame square and secure, sealing it and clearing the waste.
We give a fixed written quote after a free survey, because a bifold price depends so heavily on the exact opening that a headline number online is rarely accurate. If you are also updating a front or side entrance while the team is on site, our composite doors page sets out those options, and the full range is on our doors hub.
Worked Examples
Two real jobs from our Caerphilly team — one wide extension, one compact opening on a budget.
A rear extension in Cyncoed, Cardiff
A family extending the back of their home in Cyncoed wanted to lose the wall between the new kitchen and the garden on summer weekends, but they had heard bifolds were cold and worried about security on a corner plot. We designed a four-pane thermally broken aluminium bifold in Anthracite Grey, folding to stack on one side with a traffic door for everyday use, glazed with warm-edge double glazing and laminated outer panes.
The whole-door U-value came in around 1.4 W/m²K, so the kitchen stayed warm through the following winter, and the anti-lift blocks and multi-point locking answered the security worry. On warm days the wall of glass folds away completely. The job sat in the middle of the guide price band because of the aluminium frame and laminated glass.
A compact opening in Caerphilly
A couple in Caerphilly wanted the light and garden connection of a bifold but had a narrower opening of about 2.4 metres and a firm budget. Rather than push aluminium, we compared a three-pane uPVC bifold with an inline sliding door and let them stand in front of both at the showroom.
They chose a three-pane uPVC bifold with a low threshold for step-free access to the patio, which kept the cost at the lower end of the guide range while still giving a warm, PAS 24 rated door. Fitting the low threshold meant the kitchen tiles and the patio slabs finished almost level, so the room felt like it ran straight out to the garden.
Frequently asked questions
Common questions about bifold door warmth, security, cost, configurations and our coverage across Cardiff and Caerphilly.
Bring the garden into your home
Book a free home survey and we will measure your opening, advise on panes, thresholds and glazing and give you a fixed price for a warm, secure bifold fitted across Cardiff and Caerphilly.
