Eight-phase typical KDR sequence. Total elapsed 50 to 56 weeks for a 200 sqm replacement.
Pre-construction (months 1-6)
Architect Stages 0-3 in parallel with site survey, planning pre-app, structural engineer engagement, demolition contractor tender, and self-build mortgage application. Statutory: 8-13 weeks planning determination[Planning Portal], 8 weeks Section 80 notice[Building Act], 2 months Party Wall Act notice. These run in parallel with design but block start.
Phase 1 (Survey): weeks 0-4
HSG264 R&D asbestos survey, topographical survey, ground investigation (boreholes + trial pits), tree survey. Output: feasibility report + foundation strategy.
Phase 2 (Demolition): weeks 4-8
Soft strip, mechanical demolition, slab break-out, waste removal, site clearance. Section 80 notice must have been served at least 6 weeks earlier.
Phase 3 (Foundations): weeks 8-14
Excavation, formwork, reinforcement, concrete pour, drainage, cured slab. Building Control inspection at excavation and at pour. Foundation curing fixed.
Phase 4 (Shell): weeks 14-28
Superstructure (block/brick or timber-frame), floor zones, roof structure, roof covering, windows installed, building wind-and-watertight. Stage payment release commonly triggers here.
Phase 5 (First fix): weeks 28-36
Plumbing carcass, electrical carcass, insulation, plasterboard. Mid-stage BC inspection. Pressure tests on plumbing and air-tightness.
Phase 6 (Second fix): weeks 36-46
Plaster skim, kitchen, sanitaryware, finished electrical fittings, internal joinery, decoration, flooring.
Phase 7 (Snag): weeks 46-50
Final BC inspection, snag list compiled with contractor, defects rectification, structural warranty inspection, completion certificate issued.
Phase 8 (Move): weeks 50-56
Final mortgage drawdown, completion paid to contractor, services connected, insurance updated, move-in. VAT431NB clock starts here for DIY route claimants.
Common delays
Planning: amendments after a refusal or condition challenge add 12-24 weeks. Materials: timber-frame lead times can run 16+ weeks in 2026 from order to delivery. Weather: foundation pours in deep frost or sustained rain stop. BC sign-off: a missed inspection that requires rework adds 2-4 weeks per element.