What we build in Thornton Heath
Most Thornton Heath 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. Edwardian bay-fronted terraces, 1930s semis, larger detached homes in Purley and Sanderstead.
Extension costs in Thornton Heath
A mid-spec 25 m² extension in Thornton Heath typically lands between £86,000 and £141,000 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 | Thornton Heath all-in |
|---|---|---|
| Side return infill | 15–20 m² | £65k – £106k |
| Full-width rear | 20–30 m² | £86k – £141k |
| Wraparound | 30–45 m² | £125k – £204k |
| Double-storey rear | 40–60 m² | £168k – £275k |
Planning permission in Thornton Heath
Croydon has been publishing supplementary planning documents that speed up householder decisions. PD is the default for most rear extensions.
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 Croydon 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: usually one Party Wall Award.
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
Rear access via a side alley or garden gate speeds up muck-away and cuts labour cost noticeably.
Every quote we issue for Thornton Heath 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 Thornton Heath
Adding floor area is usually cheaper than moving once stamp duty, agent fees and moving costs are counted.
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 Thornton Heath use us
- KYB-verified builders only
- Live Croydon project experience
- Itemised fixed-price specifications
- Insurance, warranty and accreditation checks