What we build in Colindale
Most Colindale 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. Interwar semis, 1930s Metroland, larger detached villas in Totteridge and Hampstead Garden Suburb.
Extension costs in Colindale
A mid-spec 25 m² extension in Colindale typically lands between £91,000 and £151,000 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 £2750–£4200 per m² depending on glazing, structural spans and kitchen spend.
| Project | Size | Colindale all-in |
|---|---|---|
| Side return infill | 15–20 m² | £68k – £113k |
| Full-width rear | 20–30 m² | £91k – £151k |
| Wraparound | 30–45 m² | £132k – £219k |
| Double-storey rear | 40–60 m² | £177k – £294k |
Planning permission in Colindale
Barnet operates fairly standard suburban planning; most side and rear extensions land under permitted development or a straightforward householder application. Hampstead Garden Suburb is the notable exception with its own conservation regime.
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 Barnet 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 stock means one party wall — much cheaper Award process than inner London terraces.
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
Access is typically through the house, so expect dust protection, a boarded route and a skip permit from the council.
Every quote we issue for Colindale 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 Colindale
Well-executed extensions here tend to return a healthy share of their cost at resale, particularly where they add a genuine third or fourth bedroom.
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 Colindale use us
- KYB-verified builders only
- Live Barnet project experience
- Itemised fixed-price specifications
- Insurance, warranty and accreditation checks