What we build in Winchmore Hill
Most Winchmore Hill projects we scope fall into three buckets: a side-return or rear infill that fixes a dark galley kitchen, a full-width rear extension that opens the ground floor to the garden, and a rear-plus-loft package that adds a bedroom while the scaffold is already up. 1930s semis and detached homes with generous rear plots.
Extension costs in Winchmore Hill
A mid-spec 25 m² extension in Winchmore Hill typically lands between £90,000 and £145,000 all-in — that figure includes professional fees, planning and Building Control, party wall, a 12% contingency and VAT at 20%. Ex-VAT build rates run £2700–£4125 per m² depending on glazing, structural spans and kitchen spend.
| Project | Size | Winchmore Hill all-in |
|---|---|---|
| Side return infill | 15–20 m² | £68k – £109k |
| Full-width rear | 20–30 m² | £90k – £145k |
| Wraparound | 30–45 m² | £131k – £210k |
| Double-storey rear | 40–60 m² | £176k – £283k |
Planning permission in Winchmore Hill
Straightforward permitted-development pathway for most rear extensions up to 6m. Prior approval is the common route rather than a full application.
Before you assume permitted development applies to your street, check whether your street falls inside a conservation area or an Article 4 direction — both are common in Enfield and both remove PD rights for rear and side extensions. Our London planning guide walks through the tests in order.
Party wall and neighbours
Semi-detached typology keeps party wall costs modest.
Serve notice at least two months before you break ground. Budget £1,200–£2,400 per adjoining owner if they dissent and appoint their own surveyor — see the Party Wall Act guide.
Access, logistics and site set-up
Tight on-street parking means bay suspensions and timed deliveries — your builder should price this, not absorb it.
Every quote we issue for Winchmore Hill prices skip permits, parking suspensions, protection and welfare explicitly in the preliminaries — so the number you sign is the number you pay.
Value added in Winchmore Hill
Light and layout move value here more than raw square metres — spend on glazing and ceiling height.
Typical programme
- Weeks 0–4Measured survey, design and structural calcs
- Weeks 4–12Planning or lawful development certificate, party wall notices
- Weeks 12–16Tender, builder selection and contract signing
- Weeks 16–34On site: groundworks, shell, watertight, first and second fix
- Week 35Building Control sign-off, snagging and handover
Full detail in the London extension timeline guide.
Why homeowners in Winchmore Hill use us
- KYB-verified builders only
- Live Enfield project experience
- Itemised fixed-price specifications
- Insurance, warranty and accreditation checks