Bifold or sliding doors for a kitchen extension?
Sliding doors suit most kitchen extensions: bigger panes, thinner frames, more view and better sealing when they're shut, which in Ireland is most of the year. Bifolds open the whole width of the back, which is lovely on the few warm days, but you look through more frames the rest of the time.
How they open, how they seal, how they look shut, and what the opening above them needs.
Free, no obligation. One local builder prices it, not five.
- 1.4W/m²K: the most any new door or window may lose
- 13.5%VAT on doors supplied and fitted
- 1 mground-floor windows from the boundary
- €2,000–€4,000steel beam over a wide opening
Bifold and sliding, compared
| Sliding | Bifold | |
|---|---|---|
| Opening | Half to two-thirds of the width | Nearly the whole width |
| View when shut | Big panes, few frames | A frame every 0.9 to 1.2 m |
| Sealing | Fewer joints | More joints and hinges to seal |
| Space inside | None, the panels slide | The folded stack needs room |
| Everyday use | One handle, one panel | A traffic door, or fold them all |
The steel above the glass
The wider the opening, the bigger the steel above it, and in an extension it's usually a beam set into the roof. The engineer sizes it. A steel beam into the old house is €2,000 to €4,000 for the beam alone, and a wide glazed opening in the new back wall needs one too.
What the rules ask of the glass
New windows, doors and rooflights must have a U-value no worse than 1.4 W/m²K (TGD L 2022), so both types need good double or triple glazing and thermally broken frames. Under the planning exemption, a ground-floor window must be at least 1 m from the boundary it faces, which matters on a side return or a narrow garden.
Doors and windows are fixtures for VAT, so supplied and fitted as part of the build they're at 13.5%.
Plan your extension and see the cost
Nine quick taps. You see your plan build up as you go: the price range, what moves it, the planning position and the build time. Your number is only asked for at the end, if you want a real price.
A 25 m² single-storey rear extension in Ireland, mid-range, with wide glass doors and a new kitchen: €62,000 to €90,000 all in, including VAT and fees.
How this is worked out
We start from what single-storey extensions cost to build per square metre in each part of Ireland, including VAT at 13.5%, and the rates for side, wraparound, two-storey and heavily glazed extensions. Standard finishes take the lower half of the range, mid-range the upper half, and high spec or a wall of glass the glazed rate. Then we add professional fees (design, engineer, BER) and, if you want one, a new kitchen at your level of finish. Totals are rounded to the nearest €1,000. It's an estimate to plan with, never a quote: the builder prices your house after seeing it.
Questions people ask
Are bifold or sliding doors better for a kitchen extension?
Sliding doors suit most kitchen extensions: bigger panes, thinner frames, more view and better sealing when they're shut, which in Ireland is most of the year. Bifolds open the whole width of the back, which is lovely on the few warm days, but you look through more frames the rest of the time.
Do bifold doors leak?
Well-made, well-fitted bifolds don't, but they have more joints to seal than sliding doors, and the threshold detail matters. Ask the builder how the threshold drains.
Which costs more, bifold or sliding doors?
It depends on the width and the frame. The bigger cost is usually the opening: the steel above it and the threshold.
Can I have a level threshold?
Yes, with a drained threshold and the floor build-up planned for it. It needs designing before the slab goes in.
Get a free quote for your extension
Plan it in under a minute, see the cost, and one vetted builder who covers your county rings you with a proper price.