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Programme template

Double-storey extension: typically 16–22 weeks.

Two-storey side or rear extension with new bedroom over kitchen/living space, tied into the existing roof.

Durations are typical ranges for a well-run job with normal lead times — actual programmes vary with site conditions, weather and procurement.

Stage-by-stage

  1. Site set-up & demolition4–6 days
  2. ◆ BC: commencement noticeinspection / milestone
  3. Excavation & footings6–10 days
  4. ◆ BC: excavation inspectioninspection / milestone
  5. Foundations & ground floor slab6–9 days
  6. ◆ BC: DPC & drains inspectioninspection / milestone
  7. Masonry to first floor8–12 days
  8. First floor joists & deck3–5 days
  9. Masonry to wallplate8–12 days
  10. Steels & structural openings3–5 days
  11. Roof structure, tie-in & coveringExisting-roof tie-in is the weather-critical stage8–12 days
  12. Watertight: windows & doors3–5 days
  13. First fix (electrics, plumbing, carpentry)8–12 days
  14. Plastering6–9 days
  15. Plaster drying5–10 days
  16. Second fix & bathroom/kitchen install10–15 days
  17. Decoration & flooring6–10 days
  18. Snagging & clean3–5 days
  19. ◆ BC: completion inspectioninspection / milestone

Customise this programme:

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Single-storey rear extension →Loft conversion (dormer) →Wraparound extension →Full house refurbishment →New-build house (single plot) →Small residential development (2–6 plots) →