The short answer
Replacing existing patio doors with bifolds in the UK typically costs between £3,000 and £7,000 fitted, with most like-for-like swaps into the same opening landing around £3,500 to £5,500. If the existing patio opening is already the right width, the job is mainly removing the old sliding doors, fitting the new bifold set and making good. Costs rise if you want a wider opening, which needs the wall enlarging, a new structural lintel and extra making good. The new bifold set itself is the largest line, with removal, disposal and finishing adding to the total. A survey confirms whether your opening can take a bifold without structural change.
Swapping like-for-like into an existing patio opening is the cheaper route; widening the opening is what drives the cost up.
Quick reference
- Like-for-like swap (fitted)£3,500–£5,500
- Removal & disposal of old doors£150–£400
- Wider opening + linteladd £1,500–£4,000+
- Typical timescale2–5 days
What the replacement involves
If your sliding patio doors sit in an opening of around 2.4 to 3 metres, a bifold can often go straight into the same gap. The table shows indicative UK 2026 costs for that like-for-like scenario, where the existing lintel stays in place and no structural change is needed.
The largest cost is the new bifold set, followed by fitting labour. Removal and disposal of the old sliding doors, and making good around the reveals and sill, complete the job. Because the opening and its support already exist, the work is mostly swap-and-finish rather than building, which keeps the total predictable.
| Element | Typical cost | Notes |
|---|---|---|
| Remove old patio doors | £150–£400 | Including disposal |
| New bifold set (3-4 pane) | £1,800–£4,500 | Aluminium, made-to-measure |
| Fitting labour | £600–£1,500 | 1–2 fitters |
| Making good | £200–£600 | Reveals, sill, internal finish |
| Total (like-for-like) | £3,500–£5,500 | Same opening width |
Indicative UK figures for a same-width replacement; widening adds structural cost.
When the opening needs widening
Older patio doors were sometimes narrower than the wide bifold runs popular today. If you want to go wider, the wall opening must be enlarged, which brings in structural work:
- Structural engineer's calculations for a new beam.
- Supply and fit of a steel beam or lintel, often £1,500 to £4,000 or more by span.
- Building control approval for the structural change.
- Extra brickwork, plastering and floor finishing around the new reveals.
This work can roughly double the project cost compared with a same-width swap, so it is worth deciding early whether the wider opening is worth it. If the existing width already suits a sensible panel split, keeping it avoids the biggest single cost in the whole job.
Things that affect the final price
Beyond the opening itself, the bifold specification moves the price. A low or flush threshold for level access costs more than a standard one but improves the connection to a patio and is popular for a seamless indoor-outdoor feel. Triple glazing, solar-control glass and non-standard colours add to the door price. If the floor levels inside and out differ, extra groundwork may be needed for a smooth transition.
Using a registered installer means the replacement can be self-certified for Building Regulations glazing standards through a scheme such as FENSA, avoiding a separate building control fee. Check whether the quote includes removal and disposal of the old doors, the threshold type you want, and any scaffolding. As with any made-to-measure door, the survey and accurate measurement are part of the cost, and a clear itemised quote makes it easy to see exactly what you are paying for.
Is it worth replacing patio doors with bifolds?
Whether the swap is worth it depends on what you want from the opening. Sliding patio doors keep large panes of glass and a clean view but only ever open part of the span. Bifolds fold almost completely clear, throwing the whole opening open to a garden or patio, which transforms how a room connects to outside in summer. If that wide-open feel is the goal, the bifold's higher cost buys a different experience.
If you mainly value the view and easy everyday operation, a modern slimline slider may suit better and could cost less than widening for a big bifold. The lowest-cost route to a bifold is a like-for-like swap into the existing opening, avoiding structural work. Before committing, get the opening surveyed so you know whether a bifold fits as-is or needs the wall enlarging, since that single factor decides whether the project sits at the lower or upper end of the cost range.
It also helps to itemise the quote so you can see exactly what the swap involves and avoid surprises. A clear price should state whether it covers removing and disposing of the old sliding doors, the threshold type you want, any making good to the reveals and sill, and the glazing specification. If the existing opening is staying the same width, those items plus the door and fitting are usually the whole job, which keeps the figure predictable. If the quote is vague or lumps everything into one number, ask for it broken down, because that is where hidden costs hide. Comparing two itemised quotes on the same scope, rather than a bare door price against a complete installed job, is the only fair way to judge them, and it makes it obvious whether one has quietly left out the removal, the threshold or the making good that the other has included.
Frequently asked questions
Can bifolds fit in my existing patio door opening?
Often yes, if the width suits a sensible panel split. A 2.4 to 3 metre patio opening typically takes a three or four-pane bifold without structural changes, which keeps the cost down.
Do I need planning permission to replace patio doors with bifolds?
Like-for-like replacement usually falls under permitted development and needs no planning permission. Enlarging the opening, or working on a listed building or in a conservation area, may require approval, so check with your local authority.
Is it cheaper to keep the same opening size?
Yes. Keeping the existing width avoids structural work, a new lintel and extra making good, which is the single biggest saving when swapping patio doors for bifolds.
How long does the replacement take?
A like-for-like swap usually takes one to two days. If the opening is widened with a new beam and making good, allow several days to a week across the trades involved.
Will the new bifold be more energy efficient than old patio doors?
Modern bifolds with thermally broken frames and current double glazing usually outperform older patio doors, helping reduce draughts and heat loss compared with dated single or early double glazing.
Sources & further reading
- Checkatrade — bifold door cost guide
- MyJobQuote — bifold door prices
- FENSA — replacement window and door rules
Figures on this page are typical UK ranges drawn from published sources and depend on your specific opening and material. They are guidance, not a quotation.