Wraparound Extension Cost Calculator
A wraparound is a rear and a side return built as one. It is the biggest change you can make to a ground floor, and it is priced accordingly.
Open the calculator →Price a wraparound in 30 seconds
4 steps. Covers floor area, spec, structural opening and region.
How this calculator works
A wraparound is priced on total new floor area, but the structural work is what separates it from two smaller extensions built separately. Wrapping the corner means the existing rear wall largely disappears, which needs multiple steels and often a corner post — that is the single biggest line after the shell itself.
The figures exclude the kitchen, which is where a wraparound usually ends up. Budget separately: a fitted kitchen in a space this size typically runs £8,000–£30,000 depending on specification. It is worth deciding the kitchen layout before the shell is signed off, not after, because the position of the island, the run of units and the appliances all drive where drainage, gas and power need to land, and moving them once the slab is down is exactly the kind of change that turns a fixed price into a running total. Because a wraparound almost always becomes the kitchen, it is worth pricing that fit-out in parallel with the shell rather than after it — our kitchen cost calculator gives a realistic range once you know the spec. And if the corner-wrapping structure is pushing the quote higher than you hoped, it is worth seeing what a straight rear single-storey extension would cost for comparison, since losing the corner steels can save a surprising amount.
Wraparound costs by size (2026)
| Size | Typical 2026 cost | Notes |
|---|---|---|
| Small (~15 m²) | £55,000–£75,000 | Modest rear plus narrow return |
| Mid (20–25 m²) | £72,000–£105,000 | The common wraparound |
| Large (30–40 m²) | £90,000–£130,000 | Substantial open-plan ground floor |
| Extra-large (40 m²+) | £110,000–£140,000+ | Whole rear elevation reworked |
| London | £95,000–£125,000 | Typical mid-size, London rates |
| South East | £82,000–£110,000 |
Ranges match our wraparound cost guide. Kitchen fit-out is excluded throughout.
Wraparound calculator FAQs
Yes, meaningfully. One set of foundations, one roof structure, one mobilisation and one party wall process rather than two. Building the rear now and the side in three years typically costs 20–30% more in total, and you live through the disruption twice. The one caveat is cash flow: a wraparound is a single larger bill rather than two smaller ones spread over years, so the saving is real but only helps if you can fund the whole build in one go rather than staging it.
Usually yes. Permitted development covers rear and side extensions separately with their own limits; wrapping the corner generally exceeds them. Budget eight weeks for a householder decision and start the drawings early.
Because you are removing the corner of the house. That needs beams in two directions and usually a post where they meet, plus a structural engineer to size them and often padstones or new foundations beneath. It is the part of the job that must not be value-engineered. If a quote looks cheap on the structural line, ask to see the engineer's calculations behind it, because undersized steel or a skipped padstone is the kind of saving that stays invisible until cracks appear in the plaster a year or two later.
No. A wraparound usually becomes a kitchen-diner, but fit-out varies too widely to fold in — £8,000 to £30,000+ depending on units, worktops and appliances. Budget it as a separate line.
Related cost guides
- Wraparound cost guide — full 2026 pricing
- Side return calculator — price just the side element
- Kitchen extension calculator — shell plus fit-out
- House extension costs — every type compared
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