Why Timelines Matter
A clear, realistic programme is one of the most valuable documents a contractor can provide. It:
- Sets client expectations correctly
- Allows coordinated procurement of materials and appliances
- Identifies key decision points and the information needed at each stage
- Helps clients plan around the works (moving out, alternative kitchen arrangements, etc.)
An unrealistic programme — one that promises the works will complete too quickly — causes more problems than a realistic one. Build in contingency from the start.
Stage-by-Stage: Single-Storey Kitchen Extension (No Planning)
Assuming planning is not required (permitted development), the programme for a standard single-storey kitchen extension in London is:
| Stage | Duration |
|---|---|
| Design and drawings | 2–4 weeks |
| Structural engineer | 1–2 weeks (alongside design) |
| Building Control application | 2–4 weeks (full plans route) |
| Kitchen planning and order | 8–12 weeks (order lead time) |
| Groundworks and foundations | 1–2 weeks |
| Superstructure (walls, steels) | 2–3 weeks |
| Roof (flat or pitched) | 1–2 weeks |
| First-fix M&E | 1–2 weeks |
| Insulation and screed | 1 week + 4 weeks drying |
| Internal walls and plastering | 1–2 weeks |
| Second-fix M&E | 1 week |
| Kitchen installation | 1–2 weeks |
| Tiling, decoration, finishes | 2–3 weeks |
Total on-site programme: 14–22 weeks (including screed drying) Total project duration including pre-construction: 6–9 months
Stage-by-Stage: Rear Dormer Loft Conversion (Permitted Development)
| Stage | Duration |
|---|---|
| Design and drawings | 2–4 weeks |
| Structural engineer | 1–2 weeks |
| Party wall notices (if applicable) | 2 months (minimum statutory period) |
| Building Control application | 2–4 weeks |
| Scaffold erection | 1 week |
| Roof structure and dormer | 3–5 weeks |
| Roof waterproofing and windows | 1–2 weeks |
| Staircase installation | 1–2 weeks |
| First-fix M&E | 1–2 weeks |
| Insulation and plastering | 2–3 weeks |
| Bathroom fit-out | 2–3 weeks |
| Second-fix and decoration | 2–3 weeks |
| Scaffold removal | 1 week |
Total on-site programme: 14–20 weeks Total project duration including pre-construction: 5–8 months
Stage-by-Stage: Full House Refurbishment (3-Bed Terrace)
| Stage | Duration |
|---|---|
| Scope finalisation and procurement | 2–4 weeks |
| Structural works (if any) | 2–4 weeks |
| First-fix electrics | 2–3 weeks |
| First-fix plumbing | 2–3 weeks |
| Plastering | 2–3 weeks |
| Drying out | 2–4 weeks |
| Second-fix electrics | 1–2 weeks |
| Second-fix plumbing and bathrooms | 2–4 weeks |
| Kitchen installation | 1–2 weeks |
| Flooring | 1–2 weeks |
| Decoration | 2–4 weeks |
| Snagging and completion | 1–2 weeks |
Total on-site programme: 20–32 weeks Total project duration including pre-construction: 6–10 months
Extensions + Loft Conversion Combined
Combining a kitchen extension and a loft conversion on the same project extends the programme slightly (some trades overlap) but is more efficient than doing them sequentially.
Total on-site programme: 20–30 weeks Total including pre-construction: 7–12 months
The Most Common Cause of Delays
- Decision delays: Kitchens, tiles, and bathroom finishes not chosen before works start
- Material lead times: Bespoke kitchens, windows, and steels have 6–12+ week lead times
- Party wall delays: The statutory period adds up to 2 months if not started early
- Planning conditions: Discharge applications can take 8 weeks+
- Unforeseen structural issues: Discovered during strip-out
- Weather: Affects external works, particularly during screed and roof stages
RCB Design & Build
RCB produces project programmes at the pre-construction stage for every project, identifying critical-path items and procurement lead times from the outset. We flag potential delays early and build contingency into the programme rather than overpromising and underdelivering.